Mechanisms and Therapeutic Potential of Myofibroblast Transformation in Pulmonary Fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible, and fatal disease with an increasing incidence and limited therapeutic options. It is characterized by the formation and deposition of excess extracellular matrix proteins resulting in the gradual replacement of normal lung architecture by fibrous tissue. The cellular and molecular mechanism of IPF has not been fully understood. A hallmark in IPF is pulmonary fibroblast to myofibroblast transformation (FMT). During excessive lung repair upon exposure to harmful stimuli, lung fibroblasts transform into myofibroblasts under stimulation of cytokines, chemokines, and vesicles from various cells. These mediators interact with lung fibroblasts, initiating multiple signaling cascades, such as TGFβ1, MAPK, Wnt/β-catenin, NF-κB, AMPK, endoplasmic reticulum stress, and autophagy, contributing to lung FMT. Furthermore, single-cell transcriptomic analysis has revealed significant heterogeneity among lung myofibroblasts, which arise from various cell types and are adapted to the altered microenvironment during pathological lung repair. This review provides an overview of recent research on the origins of lung myofibroblasts and the molecular pathways driving their formation, with a focus on the interactions between lung fibroblasts and epithelial cells, endothelial cells, and macrophages in the context of lung fibrosis. Based on these molecular insights, targeting the lung FMT could offer promising avenues for the treatment of IPF.

Keywords

Pulmonary fibrosis / Extracellular matrix / Fibroblasts / Myofibroblasts / Cytokines

Author Contributions

Conceptualization, Y.S. and T.Z.; Writing—Original Draft Preparation, T.Z.; Writing—Review & Editing, Y.S.; Supervision, Y.S.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Funding

This research was funded in whole or in part, by US National Institute of Health grants HL134934 and HL158909 to YS, and by the Department of Veterans Affairs BX005350 to YS.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

[1] Mutsaers SE, Miles T, Prêle CM, Hoyne GF. Emerging role of immune cells as drivers of pulmonary fibrosis. Pharmacol. Ther. 2023, 252, 108562.

[2] Shao C, Shi Y, Chen R, Liu X, Huang H, Zhao Y, et al. Risk factors associated with COVID-19 pneumonia in Chinese patients with pre-existing interstitial lung disease during the SARS-CoV-2 pandemic. J. Med. Virol. 2023, 95, e29098.

[3] Leung CC, Yu IT, Chen W. Silicosis. Lancet 2012, 379, 2008-2018.

[4] Sahu KK, Mishra AK, Noreldin M. A Challenging Case of Radiation-Induced Lung Fibrosis. Am. J. Med. 2020, 133, 1158-1161.

[5] Li S, Shi J, Tang H. Animal models of drug-induced pulmonary fibrosis: An overview of molecular mechanisms and characteristics. Cell. Biol. Toxicol. 2022, 38, 699-723.

[6] Mouawad JE, Feghali-Bostwick C. The Molecular Mechanisms of Systemic Sclerosis-Associated Lung Fibrosis. Int. J. Mol. Sci. 2023, 24, 2963.

[7] Podolanczuk AJ, Thomson CC, Remy-Jardin M, Richeldi L, Martinez FJ, Kolb M, et al. Idiopathic pulmonary fibrosis: State of the art for 2023. Eur. Respir. J. 2023, 61, 4.

[8] Buechler MB, Pradhan RN, Krishnamurty AT, Cox C, Calviello AK, Wang AW, et al. Cross-tissue organization of the fibroblast lineage. Nature 2021, 593, 575-579.

[9] Tsukui T, Sun KH, Wetter JB, Wilson-Kanamori JR, Hazelwood LA, Henderson NC, et al. Collagen-producing lung cell atlas identifies multiple subsets with distinct localization and relevance to fibrosis. Nat. Commun. 2020, 11, 1920.

[10] Sahai E, Astsaturov I, Cukierman E, DeNardo DG, Egeblad M, Evans RM, et al. A framework for advancing our understanding of cancer-associated fibroblasts. Nat. Rev. Cancer 2020, 20, 174-186.

[11] Beers MF, Morrisey EE. The three R’s of lung health and disease: Repair, remodeling, and regeneration. J. Clin. Investig. 2011, 121, 2065-2073.

[12] Rajesh R, Atallah R, Bärnthaler T. Dysregulation of metabolic pathways in pulmonary fibrosis. Pharmacol. Ther. 2023, 246, 108436.

[13] Hamanaka RB, Mutlu GM. Metabolic requirements of pulmonary fibrosis: Role of fibroblast metabolism. Febs. J. 2021, 288, 6331-6352.

[14] Ni J, Dong Z, Han W, Kondrikov D, Su Y. The role of RhoA and cytoskeleton in myofibroblast transformation in hyperoxic lung fibrosis. Free. Radic. Biol. Med. 2013, 61, 26-39.

[15] Fang Y, Chung SSW, Xu L, Xue C, Liu X, Jiang D, et al. RUNX2 promotes fibrosis via an alveolar-to-pathological fibroblast transition. Nature 2025, 5, 1-10.

[16] Ma Z, Yu R, Zhu Q, Sun L, Jian L, Wang X, et al. CXCL16/CXCR6 axis promotes bleomycin-induced fibrotic process in MRC-5 cells via the PI3K/AKT/FOXO3a pathway. Int. Immunopharmacol. 2020, 81, 106035.

[17] Liu SS, Liu C, Lv XX, Cui B, Yan J, Li YX, et al. The chemokine CCL1 triggers an AMFR-SPRY1 pathway that promotes differentiation of lung fibroblasts into myofibroblasts and drives pulmonary fibrosis. Immunity 2021, 54, 2042-2056.

[18] Höhne K, Wagenknecht A, Maier C, Engelhard P, Goldmann T, Schließmann SJ, et al. Pro-Fibrotic Effects of CCL18 on Human Lung Fibroblasts Are Mediated via CCR6. Cells 2024, 13, 238.

[19] Wang QR, Liu SS, Min JL, Yin M, Zhang Y, Zhang Y, et al. CCL17 drives fibroblast activation in the progression of pulmonary fibrosis by enhancing the TGF-β/Smad signaling. Biochem. Pharmacol. 2023, 210, 115475.

[20] Ghafouri-Fard S, Askari A, Shoorei H, Seify M, Koohestanidehaghi Y, Hussen BM, et al. Antioxidant therapy against TGF-β/SMAD pathway involved in organ fibrosis. J. Cell. Mol. Med. 2024, 28, e18052.

[21] Ong CH, Tham CL, Harith HH, Firdaus N, Israf DA. TGF-β-induced fibrosis: A review on the underlying mechanism and potential therapeutic strategies. Eur. J. Pharmacol. 2021, 911, 174510.

[22] Chen H, Liu C, Zhan Y, Wang Y, Hu Q, Zeng Z. Alpinetin ameliorates bleomycin-induced pulmonary fibrosis by repressing fibroblast differentiation and proliferation. Biomed. Pharmacother. 2024, 171, 116101.

[23] Koo HY, El-Baz LM, House S, Cilvik SN, Dorry SJ, Shoukry NM, et al. Fibroblast growth factor 2 decreases bleomycin-induced pulmonary fibrosis and inhibits fibroblast collagen production and myofibroblast differentiation. J. Pathol. 2018, 246, 54-66.

[24] Sun HN, Ren CX, Lee DH, Wang WH, Guo XY, Hao YY, et al. PRDX1 negatively regulates bleomycin-induced pulmonary fibrosis via inhibiting the epithelial-mesenchymal transition and lung fibroblast proliferation in vitro and in vivo. Cell. Mol. Biol. Lett. 2023, 28, 48.

[25] Weng J, Tu M, Wang P, Zhou X, Wang C, Wan X, et al. Amiodarone induces cell proliferation and myofibroblast differentiation via ERK1/2 and p38 MAPK signaling in fibroblasts. Biomed. Pharmacother. 2019, 115, 108889.

[26] Bucala R, Spiegel LA, Chesney J, Hogan M, Cerami A. Circulating Fibrocytes Define a New Leukocyte Subpopulation That Mediates Tissue-Repair. Mol. Med. 1994, 1, 71-81.

[27] Phillips RJ, Burdick MD, Hong K, Lutz MA, Murray LA, Xue YY, et al. Circulating fibrocytes traffic to the lungs in response to CXCL12 and mediate fibrosis. J. Clin. Investig. 2004, 114, 438-446.

[28] Wang J, Tannous BA, Poznansky MC, Chen H. CXCR4 antagonist AMD3100 (plerixafor): From an impurity to a therapeutic agent. Pharmacol. Res. 2020, 159, 105010.

[29] Song JS, Kang CM, Kang HH, Yoon HK, Kim YK, Kim KH, et al. Inhibitory effect of CXC chemokine receptor 4 antagonist AMD3100 on bleomycin induced murine pulmonary fibrosis. Exp. Mol. Med. 2010, 42, 465-472.

[30] Sun Q, Tao X, Li B, Cao H, Chen H, Zou Y, et al. C-X-C-Chemokine-Receptor-Type-4 Inhibitor AMD3100 Attenuates Pulmonary Inflammation and Fibrosis in Silicotic Mice. J. Inflamm. Res. 2022, 15, 5827-5843.

[31] Heukels P, van Hulst JAC, van Nimwegen M, Boorsma CE, Melgert BN, van den Toorn LM, et al. Fibrocytes are increased in lung and peripheral blood of patients with idiopathic pulmonary fibrosis. Respir. Res. 2018, 19, 90.

[32] Niu XH, Xie YP, Yang S, Chen Y, Xu L, Zhang Y, et al. IL-18/IL-18R1 promotes circulating fibrocyte differentiation in the aging population. Inflamm. Res. Off. J. Eur. Histamine Res. Soc. 2020, 69, 497-507.

[33] Stewart ID, Nanji H, Figueredo G, Fahy WA, Maher TM, Ask AJ, et al. Circulating fibrocytes are not disease-specific prognosticators in idiopathic pulmonary fibrosis. Eur. Respir. J. 2021, 58, 25.

[34] Gomez-Manjarres DC, Axell-House DB, Patel DC, Odackal J, Yu V, Burdick MD, et al. Sirolimus suppresses circulating fibrocytes in idiopathic pulmonary fibrosis in a randomized controlled crossover trial. JCI Insight 2023, 8, e166901.

[35] Mehrad B, Burdick MD, Strieter RM. Fibrocyte CXCR4 regulation as a therapeutic target in pulmonary fibrosis. Int. J. Biochem. Cell. Biol. 2009, 41, 1708-1718.

[36] Lingampally A, Jones MR, Bagari S, Chen C, Rivetti S, Bellusci S. Use of the Reversible Myogenic to Lipogenic Transdifferentiation Switch for the Design of Pre-clinical Drug Screening in Idiopathic Pulmonary Fibrosis. Front. Bioeng. Biotechnol. 2020, 8, 569865.

[37] El Agha E, Moiseenko A, Kheirollahi V, De Langhe S, Crnkovic S, Kwapiszewska G, et al. Two-Way Conversion between Lipogenic and Myogenic Fibroblastic Phenotypes Marks the Progression and Resolution of Lung Fibrosis. Cell. Stem. Cell. 2017, 20, 261-273.e263.

[38] Trempus CS, Papas BN, Sifre MI, Bortner CD, Scappini E, Tucker CJ, et al. Functional Pdgfra fibroblast heterogeneity in normal and fibrotic mouse lung. JCI Insight 2023, 8, e164380.

[39] Rehan M, Deskin B, Kurundkar AR, Yadav S, Matsunaga Y, Manges J, et al. Nicotinamide N-methyltransferase mediates lipofibroblast-myofibroblast transition and apoptosis resistance. J. Biol. Chem. 2023, 299, 105027.

[40] Belgacemi R, Cherry C, El Alam I, Frauenpreis A, Glass I, Bellusci S, et al. Preferential FGF18/FGFR activity in pseudoglandular versus canalicular stage human lung fibroblasts. Front. Cell Dev. Biol. 2023, 11, 1220002.

[41] Tong L, Zhou J, Rong L, Seeley EJ, Pan J, Zhu X, et al. Fibroblast Growth Factor-10 (FGF-10) Mobilizes Lung-resident Mesenchymal Stem Cells and Protects Against Acute Lung Injury. Sci. Rep. 2016, 6, 21642.

[42] Xie T, Liang J, Liu N, Huan C, Zhang Y, Liu W, et al. Transcription factor TBX4 regulates myofibroblast accumulation and lung fibrosis. J. Clin. Investig. 2016, 126, 3063-3079.

[43] Lu Y, Liu Z, Zhang Y, Wu X, Bian W, Shan S, et al. METTL3-mediated m6A RNA methylation induces the differentiation of lung resident mesenchymal stem cells into myofibroblasts via the miR-21/PTEN pathway. Respir. Res. 2023, 24, 300.

[44] Sveiven SN, Nordgren TM. Lung-resident mesenchymal stromal cells are tissue-specific regulators of lung homeostasis. Am. J. Physiol. Lung Cell Mol. Physiol. 2020, 319, L197-L210.

[45] Sun W, Liu X, Yang X, Jing X, Duan C, Yang G, et al. SENP1 regulates the transformation of lung resident mesenchymal stem cells and is associated with idiopathic pulmonary fibrosis progression. Cell. Commun. Signal 2022, 20, 104.

[46] Michiels C.Endothelial cell functions. J. Cell. Physiol. 2003, 196, 430-443.

[47] Hashimoto N, Phan SH, Imaizumi K, Matsuo M, Nakashima H, Kawabe T, et al. Endothelial-mesenchymal transition in bleomycin-induced pulmonary fibrosis. Am. J. Respir. Cell. Mol. Biol. 2010, 43, 161-172.

[48] Zhang X, Xu Z, Chen Q, Zhou Z.Notch signaling regulates pulmonary fibrosis. Front. Cell. Dev. Biol. 2024, 12, 1450038.

[49] Yin Q, Wang W, Cui G, Yan L, Zhang S. Potential role of the Jagged1/Notch1 signaling pathway in the endothelial-myofibroblast transition during BLM-induced pulmonary fibrosis. J. Cell. Physiol. 2018, 233, 2451-2463.

[50] Ou XM, Li WC, Liu DS, Li YP, Wen FQ, Feng YL, et al. VEGFR-2 antagonist SU5416 attenuates bleomycin-induced pulmonary fibrosis in mice. Int. Immunopharmacol. 2009, 9, 70-79.

[51] Iyer AK, Ramesh V, Castro CA, Kaushik V, Kulkarni YM, Wright CA, et al. Nitric oxide mediates bleomycin-induced angiogenesis and pulmonary fibrosis via regulation of VEGF. J. Cell. Biochem. 2015, 116, 2484-2493.

[52] Farkas L, Gauldie J, Voelkel NF, Kolb M. Pulmonary hypertension and idiopathic pulmonary fibrosis: A tale of angiogenesis, apoptosis, and growth factors. Am. J. Respir. Cell. Mol. Biol. 2011, 45, 1-15.

[53] May J, Mitchell JA, Jenkins RG. Beyond epithelial damage: Vascular and endothelial contributions to idiopathic pulmonary fibrosis. J. Clin. Investig. 2023, 133, 18.

[54] Wu X, Zhang D, Qiao X, Zhang L, Cai X, Ji J, et al. Regulating the cell shift of endothelial cell-like myofibroblasts in pulmonary fibrosis. Eur. Respir. J. 2023, 61, 6.

[55] Wu X, Zhang D, Bostrom KI, Yao Y. COVID-19 Infection May Drive EC-like Myofibroblasts towards Myofibroblasts to Contribute to Pulmonary Fibrosis. Int. J. Mol. Sci. 2023, 24, 11500.

[56] Li S, Liu Z, Jiao X, Gu J, Liu Z, Meng L, et al. Selpercatinib attenuates bleomycin-induced pulmonary fibrosis by inhibiting the TGF-beta1 signaling pathway. Biochem. Pharmacol. 2024, 225, 116282.

[57] Willis BC, duBois RM, Borok Z. Epithelial origin of myofibroblasts during fibrosis in the lung. Proc. Am. Thorac. Soc. 2006, 3, 377-382.

[58] Rock JR, Barkauskas CE, Cronce MJ, Xue Y, Harris JR, Liang J, et al. Multiple stromal populations contribute to pulmonary fibrosis without evidence for epithelial to mesenchymal transition. Proc. Natl. Acad. Sci. USA 2011, 108, E1475-E1483.

[59] Wu Y, Shi W, Li H, Liu C, Shimizu K, Li R, et al. Specneuzhenide improves bleomycin-induced pulmonary fibrosis in mice via AMPK-dependent reduction of PD-L1. Phytomed. Int. J. Phytother. Phytopharm. 2024, 128, 155318.

[60] Fernandez IE, Eickelberg O. New cellular and molecular mechanisms of lung injury and fibrosis in idiopathic pulmonary fibrosis. Lancet 2012, 380, 680-688.

[61] Wang YC, Chen Q, Luo JM, Nie J, Meng QH, Shuai W, et al.Notch1 promotes the pericyte-myofibroblast transition in idiopathic pulmonary fibrosis through the PDGFR/ROCK1 signal pathway. Exp. Mol. Med. 2019, 51, 1-11.

[62] Kuppe C, Ibrahim MM, Kranz J, Zhang X, Ziegler S, Perales-Patón J, et al. Decoding myofibroblast origins in human kidney fibrosis. Nature 2021, 589, 281-286.

[63] Rowley JE, Johnson JR.Pericytes in chronic lung disease. Int. Arch. Allergy Immunol. 2014, 164, 178-188.

[64] Sava P, Ramanathan A, Dobronyi A, Peng X, Sun H, Ledesma-Mendoza A, et al. Human pericytes adopt myofibroblast properties in the microenvironment of the IPF lung. JCI Insight 2017, 2, e96352.

[65] Hung C, Linn G, Chow YH, Kobayashi A, Mittelsteadt K, Altemeier WA, et al. Role of lung pericytes and resident fibroblasts in the pathogenesis of pulmonary fibrosis. Am. J. Respir. Crit. Care Med. 2013, 188, 820-830.

[66] Nho RS, Xia H, Diebold D, Kahm J, Kleidon J, White E, et al. PTEN regulates fibroblast elimination during collagen matrix contraction. J. Biol. Chem. 2006, 281, 33291-33301.

[67] Bonella F, Spagnolo P, Ryerson C. Current and Future Treatment Landscape for Idiopathic Pulmonary Fibrosis. Drugs 2023, 83, 1581-1593.

[68] Vuga LJ, Ben-Yehudah A, Kovkarova-Naumovski E, Oriss T, Gibson KF, Feghali-Bostwick C, et al. WNT5A is a regulator of fibroblast proliferation and resistance to apoptosis. Am. J. Respir. Cell. Mol. Biol. 2009, 41, 583-589.

[69] Sha JM, Zhang RQ, Wang XC, Zhou Y, Song K, Sun H, et al. Epigenetic reader MeCP2 repressed WIF1 boosts lung fibroblast proliferation, migration and pulmonary fibrosis. Toxicol. Lett. 2023, 381, 1-12.

[70] Huang C, Liang C, Tong J, Zhong X, Luo L, Liang L, et al. Soluble E-cadherin participates in BLM-induced pulmonary fibrosis by promoting EMT and lung fibroblast migration. Environ. Toxicol. 2024, 39, 435-443.

[71] Teles-Grilo ML, Leite-Almeida H, dos Santos JM, Oliveira C, Boaventura P, Grande NR. Differential expression of collagens type I and type IV in lymphangiogenesis during the angiogenic process associated with bleomycin-induced pulmonary fibrosis in rat. Lymphology 2005, 38, 130-135.

[72] Merl-Pham J, Basak T, Knüppel L, Ramanujam D, Athanason M, Behr J, et al. Quantitative proteomic profiling of extracellular matrix and site-specific collagen post-translational modifications in an in vitro model of lung fibrosis. Matrix. Biol. Plus. 2019, 1, 100005.

[73] Urushiyama H, Terasaki Y, Nagasaka S, Terasaki M, Kunugi S, Nagase T, et al. Role of α1 and α2 chains of type IV collagen in early fibrotic lesions of idiopathic interstitial pneumonias and migration of lung fibroblasts. Lab. Investig. 2015, 95, 872-885.

[74] Buhling F, Wille A, Rocken C, Wiesner O, Baier A, Meinecke I, et al. Altered expression of membrane-bound and soluble CD95/Fas contributes to the resistance of fibrotic lung fibroblasts to FasL induced apoptosis. Respir. Res. 2005, 6, 37.

[75] Nareznoi D, Konikov-Rozenman J, Petukhov D, Breuer R, Wallach-Dayan SB. Matrix Metalloproteinases Retain Soluble FasL-mediated Resistance to Cell Death in Fibrotic-Lung Myofibroblasts. Cells 2020, 9, 411.

[76] Redente EF, Chakraborty S, Sajuthi S, Black BP, Edelman BL, Seibold MA, et al. Loss of Fas signaling in fibroblasts impairs homeostatic fibrosis resolution and promotes persistent pulmonary fibrosis. JCI Insight 2020, 6, e141618.

[77] Nho RS, Peterson M, Hergert P, Henke CA. FoxO3a (Forkhead Box O3a) deficiency protects Idiopathic Pulmonary Fibrosis (IPF) fibroblasts from type I polymerized collagen matrix-induced apoptosis via caveolin-1 (cav-1) and Fas. PLoS ONE 2013, 8, e61017.

[78] Lin JH, Liu CC, Liu CY, Hsu TW, Yeh YC, How CK, et al. Selenite selectively kills lung fibroblasts to treat bleomycin-induced pulmonary fibrosis. Redox. Biol. 2024, 72, 103148.

[79] Demaria M, Ohtani N, Youssef SA, Rodier F, Toussaint W, Mitchell JR, et al. An essential role for senescent cells in optimal wound healing through secretion of PDGF-AA. Dev. Cell. 2014, 31, 722-733.

[80] Wilkinson HN, Clowes C, Banyard KL, Matteuci P, Mace KA, Hardman MJ. Elevated Local Senescence in Diabetic Wound Healing Is Linked to Pathological Repair via CXCR2. J. Investig. Dermatol. 2019, 139, 1171-1181.e1176.

[81] Fortier SM, Walker NM, Penke LR, Baas JD, Shen Q, Speth JM, et al. MAPK phosphatase 1 inhibition of p38α within lung myofibroblasts is essential for spontaneous fibrosis resolution. J. Clin. Investig. 2024, 134, 10.

[82] Fortier SM, Penke LR, King D, Pham TX, Ligresti G, Peters-Golden M. Myofibroblast dedifferentiation proceeds via distinct transcriptomic and phenotypic transitions. JCI Insight 2021, 6, e144799.

[83] Zhang Y, Fu J, Li C, Chang Y, Li X, Cheng H, et al. Omentin-1 induces mechanically activated fibroblasts lipogenic differentiation through pkm2/yap/pparγ pathway to promote lung fibrosis resolution. Cell. Mol. Life Sci. 2023, 80, 308.

[84] Kheirollahi V, Wasnick RM, Biasin V, Vazquez-Armendariz AI, Chu X, Moiseenko A, et al. Metformin induces lipogenic differentiation in myofibroblasts to reverse lung fibrosis. Nat. Commun. 2019, 10, 2987.

[85] Ugai K, Matsuda S, Mikami H, Shimada A, Misawa T, Nakamura H, et al. Inhibition of the SET8 Pathway Ameliorates Lung Fibrosis Even Through Fibroblast Dedifferentiation. Front. Mol. Biosci. 2020, 7, 192.

[86] Xu R, Wu M, Wang Y, Li C, Zeng L, Wang Y, et al. Mesenchymal stem cells reversibly de-differentiate myofibroblasts to fibroblast-like cells by inhibiting the TGF-β-SMAD2/3 pathway. Mol. Med. 2023, 29, 59.

[87] Walsh SM, Worrell JC, Fabre A, Hinz B, Kane R, Keane MP. Novel differences in gene expression and functional capabilities of myofibroblast populations in idiopathic pulmonary fibrosis. Am. J. Physiol. Lung Cell. Mol. Physiol. 2018, 315, L697-L710.

[88] Hinz B, Phan SH, Thannickal VJ, Galli A, Bochaton-Piallat ML, Gabbiani G. The myofibroblast: One function, multiple origins. Am. J. Pathol. 2007, 170, 1807-1816.

[89] Hinz B, Celetta G, Tomasek JJ, Gabbiani G, Chaponnier C. Alpha-smooth muscle actin expression upregulates fibroblast contractile activity. Mol. Biol. Cell. 2001, 12, 2730-2741.

[90] Sun KH, Chang Y, Reed NI, Sheppard D. alpha-Smooth muscle actin is an inconsistent marker of fibroblasts responsible for force-dependent TGFbeta activation or collagen production across multiple models of organ fibrosis. Am. J. Physiol. Lung Cell. Mol. Physiol. 2016, 310, L824-L836.

[91] Liu X, Dai K, Zhang X, Huang G, Lynn H, Rabata A, et al. Multiple Fibroblast Subtypes Contribute to Matrix Deposition in Pulmonary Fibrosis. Am. J. Respir. Cell. Mol. Biol. 2023, 69, 45-56.

[92] Layton TB, Williams L, McCann F, Zhang M, Fritzsche M, Colin-York H, et al. Cellular census of human fibrosis defines functionally distinct stromal cell types and states. Nat. Commun. 2020, 11, 2768.

[93] Xie T, Wang Y, Deng N, Huang G, Taghavifar F, Geng Y, et al. Single-Cell Deconvolution of Fibroblast Heterogeneity in Mouse Pulmonary Fibrosis. Cell. Rep. 2018, 22, 3625-3640.

[94] Frangogiannis N. Transforming growth factor-β in tissue fibrosis. J. Exp. Med. 2020, 217, e20190103.

[95] Massagué J, Sheppard D. TGF-β signaling in health and disease. Cell 2023, 186, 4007-4037.

[96] Groppe J, Hinck CS, Samavarchi-Tehrani P, Zubieta C, Schuermann JP, Taylor AB, et al. Cooperative assembly of TGF-beta superfamily signaling complexes is mediated by two disparate mechanisms and distinct modes of receptor binding. Mol. Cell. 2008, 29, 157-168.

[97] Hu HH, Chen DQ, Wang YN, Feng YL, Cao G, Vaziri ND, et al. New insights into TGF-β/Smad signaling in tissue fibrosis. Chem. Biol. Interact. 2018, 292, 76-83.

[98] Ju X, Wang K, Wang C, Zeng C, Wang Y, Yu J. Regulation of myofibroblast dedifferentiation in pulmonary fibrosis. Respir. Res. 2024, 25, 284.

[99] Meng XM, Nikolic-Paterson DJ, Lan HY. TGF-β: The master regulator of fibrosis. Nat. Rev. Nephrol. 2016, 12, 325-338.

[100] Batlle E, Massague J. Transforming Growth Factor-beta Signaling in Immunity and Cancer. Immunity 2019, 50, 924-940.

[101] Dutta A, Hutchison RE, Mohi G. Hmga2 promotes the development of myelofibrosis in Jak2(V617F) knockin mice by enhancing TGF-beta1 and Cxcl12 pathways. Blood 2017, 130, 920-932.

[102] Finnson KW, Almadani Y, Philip A. Non-canonical (non-SMAD2/3) TGF-β signaling in fibrosis: Mechanisms and targets. Semin. Cell. Dev. Biol. 2020, 101, 115-122.

[103] Wang F, Wang S, Zhang C, Tian X, Zhou Y, Xuan W, et al. Noncanonical JAK1/STAT3 interactions with TGF-β modulate myofibroblast transdifferentiation and fibrosis. Am. J. Physiol. Lung Cell Mol. Physiol. 2022, 323, L698-l714.

[104] Fernandez IE, Eickelberg O. The impact of TGF-β on lung fibrosis: From targeting to biomarkers. Proc. Am. Thorac. Soc. 2012, 9, 111-116.

[105] Kim KK, Sheppard D, Chapman HA. TGF-β1 Signaling and Tissue Fibrosis. Cold Spr. Harb. Perspect. Biol. 2018, 10, a022293.

[106] Chanda D, Otoupalova E, Smith SR, Volckaert T, De Langhe SP, Thannickal VJ. Developmental pathways in the pathogenesis of lung fibrosis. Mol. Asp. Med. 2019, 65, 56-69.

[107] Sime PJ, Xing Z, Graham FL, Csaky KG, Gauldie J. Adenovector-mediated gene transfer of active transforming growth factor-beta1 induces prolonged severe fibrosis in rat lung. J. Clin. Investig. 1997, 100, 768-776.

[108] Yao Y, Wang Y, Zhang Z, He L, Zhu J, Zhang M, et al. Chop Deficiency Protects Mice Against Bleomycin-induced Pulmonary Fibrosis by Attenuating M2 Macrophage Production. Mol. Ther. 2016, 24, 915-925.

[109] Guo X, Sunil C, Adeyanju O, Parker A, Huang S, Ikebe M, et al. PD-L1 mediates lung fibroblast to myofibroblast transition through Smad3 and β-catenin signaling pathways. Sci. Rep. 2022, 12, 3053.

[110] Kang JH, Jung MY, Choudhury M, Leof EB. Transforming growth factor beta induces fibroblasts to express and release the immunomodulatory protein PD-L1 into extracellular vesicles. FASEB J. 2020, 34, 2213-2226.

[111] Geng Y, Liu X, Liang J, Habiel DM, Kulur V, Coelho AL, et al. PD-L1 on invasive fibroblasts drives fibrosis in a humanized model of idiopathic pulmonary fibrosis. JCI Insight 2019, 4, e125326.

[112] Hu B, Zhang X, Fan H, Jin X, Qi Y, Liu R, et al.FOXF1 reverses lung fibroblasts transdifferentiation via inhibiting TGF-β/SMAD2/3 pathway in silica-induced pulmonary fibrosis. Int. Immunopharmacol. 2024, 133, 112067.

[113] Johnson GL, Lapadat R. Mitogen-activated protein kinase pathways mediated by ERK, JNK, and p 38 protein kinases. Science 2002, 298, 1911-1912.

[114] Ding Q, Gladson CL, Wu H, Hayasaka H, Olman MA. Focal adhesion kinase (FAK)-related non-kinase inhibits myofibroblast differentiation through differential MAPK activation in a FAK-dependent manner. J. Biol. Chem. 2008, 283, 26839-26849.

[115] Wang Y, Cheng D, Li Z, Sun W, Zhou S, Peng L, et al. IL33-mediated NPM1 promotes fibroblast-to-myofibroblast transition via ERK/AP-1 signaling in silica-induced pulmonary fibrosis. Toxicol. Sci. Off. J. Soc. Toxicol. 2023, 195, 71-86.

[116] Ng B, Dong J, D’Agostino G, Viswanathan S, Widjaja AA, Lim WW, et al. Interleukin-11 is a therapeutic target in idiopathic pulmonary fibrosis. Sci. Transl. Med. 2019, 11, eaaw1237.

[117] Xu H, Yang J, Tu M, Weng J, Xie M, Zhou Z, et al. Vincristine Promotes Transdifferentiation of Fibroblasts Into Myofibroblasts via P38 and ERK Signal Pathways. Front. Pharmacol. 2022, 13, 901000.

[118] Sarikhani M, Mishra S, Desingu PA, Kotyada C, Wolfgeher D, Gupta MP, et al. SIRT2 regulates oxidative stress-induced cell death through deacetylation of c-Jun NH(2)-terminal kinase. Cell. Death. Differ. 2018, 25, 1638-1656.

[119] Justet A, Ghanem M, Boghanim T, Hachem M, Vasarmidi E, Jaillet M, et al. FGF19 Is Downregulated in Idiopathic Pulmonary Fibrosis and Inhibits Lung Fibrosis in Mice. Am. J. Respir. Cell. Mol. Biol. 2022, 67, 173-187.

[120] Horan G, Ye Y, Adams M, Parton A, Cedzik D, Tang S, et al. Safety, Pharmacokinetics, and Antifibrotic Activity of CC-90001 (BMS-986360), a c-Jun N-Terminal Kinase Inhibitor, in Pulmonary Fibrosis. Clin. Pharmacol. Drug. Dev. 2023, 12, 779-789.

[121] Mattos W, Khalil N, Spencer LG, Bonella F, Folz RJ, Rolf JD, et al. Phase 2, Double-Blind, Placebo-controlled Trial of a c-Jun N-Terminal Kinase Inhibitor in Idiopathic Pulmonary Fibrosis. Am. J. Respir. Crit. Care. Med. 2024, 210, 435-443.

[122] Popmihajlov Z, Sutherland DJ, Horan GS, Ghosh A, Lynch DA, Noble PW, et al Greenberg S., CC-90001, a c-Jun N-terminal kinase (JNK) inhibitor, in patients with pulmonary fibrosis: Design of a phase 2, randomised, placebo-controlled trial. BMJ Open Respir. Res. 2022, 9, e001060.

[123] Vind AC, Genzor AV, Bekker-Jensen S. Ribosomal stress-surveillance: Three pathways is a magic number. Nucleic Acids. Res. 2020, 48, 10648-10661.

[124] Sato N, Takasaka N, Yoshida M, Tsubouchi K, Minagawa S, Araya J, et al. Metformin attenuates lung fibrosis development via NOX4 suppression. Respir. Res. 2016, 17, 107.

[125] Ji H, Dong H, Lan Y, Bi Y, Gu X, Han Y, et al. Metformin attenuates fibroblast activation during pulmonary fibrosis by targeting S100A4 via AMPK-STAT3 axis. Front. Pharmacol. 2023, 14, 1089812.

[126] Bo C, Liu F, Zhang Z, Du Z, Xiu H, Zhang Z, et al. Simvastatin attenuates silica-induced pulmonary inflammation and fibrosis in rats via the AMPK-NOX pathway. BMC Pulm. Med. 2024, 24, 224.

[127] Tirunavalli SK, Andugulapati SB. Geneticin ameliorates pulmonary fibrosis by attenuating the TGF-β/Smad via modulating AMPK/SIRT1 signaling. Life Sci. 2024, 346, 122626.

[128] Wang L, Xu K, Wang N, Ding L, Zhao W, Wan R, et al. Fenbendazole Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice via Suppression of Fibroblast-to-Myofibroblast Differentiation. Int. J. Mol. Sci. 2022, 23, 14088.

[129] Patel AS, Lin L, Geyer A, Haspel JA, An CH, Cao J, et al.Autophagy in idiopathic pulmonary fibrosis. PLoS ONE 2012, 7, e41394.

[130] Kim J, Kundu M, Viollet B, Guan KL. AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1. Nat. Cell. Biol. 2011, 13, 132-141.

[131] Agostini F, Bisaglia M, Plotegher N. Linking ROS Levels to Autophagy: The Key Role of AMPK. Antioxidants 2023, 12, 1406.

[132] Skronska-Wasek W, Gosens R, Konigshoff M, Baarsma HA. WNT receptor signalling in lung physiology and pathology. Pharmacol. Ther. 2018, 187, 150-166.

[133] Cao H, Wang C, Chen X, Hou J, Xiang Z, Shen Y, et al. Inhibition of Wnt/beta-catenin signaling suppresses myofibroblast differentiation of lung resident mesenchymal stem cells and pulmonary fibrosis. Sci. Rep. 2018, 8, 13644.

[134] Konigshoff M, Kramer M, Balsara N, Wilhelm J, Amarie OV, Jahn A, et al. WNT1-inducible signaling protein-1 mediates pulmonary fibrosis in mice and is upregulated in humans with idiopathic pulmonary fibrosis. J. Clin. Investig. 2009, 119, 772-787.

[135] Shi C, Chen X, Yin W, Sun Z, Hou J, Han X. Wnt8b regulates myofibroblast differentiation of lung-resident mesenchymal stem cells via the activation of Wnt/beta-catenin signaling in pulmonary fibrogenesis. Differentiation 2022, 125, 35-44.

[136] Min J, Li Q, Liu S, Wang Q, Yin M, Zhang Y, et al. TRAF6 Suppresses the Development of Pulmonary Fibrosis by Attenuating the Activation of Fibroblasts. Front. Pharmacol. 2022, 13, 911945.

[137] Akhmetshina A, Palumbo K, Dees C, Bergmann C, Venalis P, Zerr P, et al. Activation of canonical Wnt signalling is required for TGF-beta-mediated fibrosis. Nat. Commun. 2012, 3, 735.

[138] Xu L, Cui WH, Zhou WC, Li DL, Li LC, Zhao P, et al. Activation of Wnt/beta-catenin signalling is required for TGF-beta/Smad2/3 signalling during myofibroblast proliferation. J. Cell. Mol. Med. 2017, 21, 1545-1554.

[139] Trinh-Minh T, Chen CW, Tran Manh C, Li YN, Zhu H, Zhou X, et al. Noncanonical WNT5A controls the activation of latent TGF-beta to drive fibroblast activation and tissue fibrosis. J. Clin. Investig. 2024, 134, 10.

[140] Hou J, Ma T, Cao H, Chen Y, Wang C, Chen X, et al. TNF-α-induced NF-κB activation promotes myofibroblast differentiation of LR-MSCs and exacerbates bleomycin-induced pulmonary fibrosis. J. Cell. Physiol. 2018, 233, 2409-2419.

[141] Sugiura H, Ichikawa T, Koarai A, Yanagisawa S, Minakata Y, Matsunaga K, et al. Activation of Toll-like receptor 3 augments myofibroblast differentiation. Am. J. Respir. Cell. Mol. Biol. 2009, 40, 654-662.

[142] Wang Q, Wang J, Wang J, Hong S, Han F, Chen J, et al. HMGB1 induces lung fibroblast to myofibroblast differentiation through NF-κB-mediated TGF-β1 release. Mol. Med. Rep. 2017, 15, 3062-3068.

[143] Zou M, Zou J, Hu X, Zheng W, Zhang M, Cheng Z. Latent Transforming Growth Factor-β Binding Protein-2 Regulates Lung Fibroblast-to-Myofibroblast Differentiation in Pulmonary Fibrosis via NF-κB Signaling. Front. Pharmacol. 2021, 12, 788714.

[144] Zhang Q, Tu W, Tian K, Han L, Wang Q, Chen P, et al. Sirtuin 6 inhibits myofibroblast differentiation via inactivating transforming growth factor-β1/Smad2 and nuclear factor-κB signaling pathways in human fetal lung fibroblasts. J. Cell. Biochem. 2019, 120, 93-104.

[145] Chen G, Li J, Liu H, Zhou H, Liu M, Liang D, et al. Cepharanthine Ameliorates Pulmonary Fibrosis by Inhibiting the NF-kappaB/NLRP3 Pathway, Fibroblast-to-Myofibroblast Transition and Inflammation. Molecules 2023, 28, 753.

[146] Zhang Q, Ye W, Liu Y, Niu D, Zhao X, Li G, et al. S-allylmercapto-N-acetylcysteine ameliorates pulmonary fibrosis in mice via Nrf2 pathway activation and NF-κB, TGF-β1/Smad2/3 pathway suppression. Biomed. Pharmacother. 2023, 157, 114018.

[147] Jaffar J, Glaspole I, Symons K, Westall G. Inhibition of NF-κB by ACT 001 reduces fibroblast activity in idiopathic pulmonary fibrosis. Biomed. Pharmacother. 2021, 138, 111471.

[148] Araya J, Kojima J, Takasaka N, Ito S, Fujii S, Hara H, et al. Insufficient autophagy in idiopathic pulmonary fibrosis. Am. J. Physiol. Lung Cell. Mol. Physiol. 2013, 304, L56-L69.

[149] Zhang X, Hu X, Zhang Y, Liu B, Pan H, Liu Z, et al. Impaired autophagy-accelerated senescence of alveolar type II epithelial cells drives pulmonary fibrosis induced by single-walled carbon nanotubes. J. Nanobiotech. 2023, 21, 69.

[150] Del Principe D, Vona R, Giordani L, Straface E, Giammarioli AM. Defective autophagy in fibroblasts may contribute to fibrogenesis in autoimmune processes. Curr. Pharm. Des. 2011, 17, 3878-3887.

[151] Zhao H, Wang Y, Qiu T, Liu W, Yao P. Autophagy, an important therapeutic target for pulmonary fibrosis diseases. Clin. Chim. Acta Int. J. Clin. Chem. 2020, 502, 139-147.

[152] Ghavami S, Yeganeh B, Zeki AA, Shojaei S, Kenyon NJ, Ott S, et al. Autophagy and the unfolded protein response promote profibrotic effects of TGF-β(1) in human lung fibroblasts. Am. J. Physiol. Lung Cell. Mol. Physiol. 2018, 314, L493-l504.

[153] Zhu Q, Wang J, Ji Y, Luan J, Yue D, Liu W, et al. Danshensu methyl ester enhances autophagy to attenuate pulmonary fibrosis by targeting lncIAPF-HuR complex. Front. Pharmacol. 2022, 13, 1013098.

[154] Lee C, Kwak SH, Han J, Shin JH, Yoo B, Lee YS, et al. Repositioning of ezetimibe for the treatment of idiopathic pulmonary fibrosis. Eur. Respir. J. 2024, 63, 5.

[155] Zheng D, Guo J, Liang Z, Jin Y, Ding Y, Liu J, et al. Supramolecular Nanofibers Ameliorate Bleomycin-Induced Pulmonary Fibrosis by Restoring Autophagy. Adv. Sci. 2024, 11, e2401327.

[156] Tabas I, Ron D. Integrating the mechanisms of apoptosis induced by endoplasmic reticulum stress. Nat. Cell Biol. 2011, 13, 184-190.

[157] Zhao T, Du J, Zeng H. Interplay between endoplasmic reticulum stress and non-coding RNAs in cancer. J. Hematol. Oncol. 2020, 13, 163.

[158] Lee HY, Kim HK, Hoang TH, Yang S, Kim HR, Chae HJ. The correlation of IRE1α oxidation with Nox4 activation in aging-associated vascular dysfunction. Redox. Biol. 2020, 37, 101727.

[159] Xu Q, Liu H, Fan XDS, Lv W, Jiang Y, Liang Y, et al. PGC-1α regulates endoplasmic reticulum stress in IPF-derived fibroblasts. Int. Immunopharmacol. 2024, 138, 112514.

[160] Baek HA, Kim DS, Park HS, Jang KY, Kang MJ, Lee DG, et al. Involvement of endoplasmic reticulum stress in myofibroblastic differentiation of lung fibroblasts. Am. J. Respir. Cell. Mol. Biol. 2012, 46, 731-739.

[161] Zimmerman KA, Graham LV, Pallero MA, Murphy-Ullrich JE. Calreticulin regulates transforming growth factor-β-stimulated extracellular matrix production. J. Biol. Chem. 2013, 288, 14584-14598.

[162] Yang X, Sun W, Jing X, Zhang Q, Huang H, Xu Z. Endoplasmic reticulum stress modulates the fate of lung resident mesenchymal stem cell to myofibroblast via C/EBP homologous protein during pulmonary fibrosis. Stem. Cell. Res. Ther. 2022, 13, 279.

[163] Chen YC, Chen BC, Huang HM, Lin SH, Lin CH. Activation of PERK in ET-1-and thrombin-induced pulmonary fibroblast differentiation: Inhibitory effects of curcumin. J. Cell. Physiol. 2019, 234, 15977-15988.

[164] Shin KWD, Atalay MV, Cetin-Atalay R, O’Leary EM, Glass ME, Szafran JCH, et al. ATF4 and mTOR regulate metabolic reprogramming in TGF-β-treated lung fibroblasts. bioRxiv 2024. doi:10.1101/2024.06.12.598694.

[165] Rackow AR, Judge JL, Woeller CF, Sime PJ, Kottmann RM. miR-338-3p blocks TGFβ-induced myofibroblast differentiation through the induction of PTEN. Am. J. Physiol. Lung Cell. Mol. Physiol. 2022, 322, L385-l400.

[166] Wu Q, Han L, Gui W, Wang F, Yan W, Jiang H. MiR-503 suppresses fibroblast activation and myofibroblast differentiation by targeting VEGFA and FGFR1 in silica-induced pulmonary fibrosis. J. Cell. Mol. Med. 2020, 24, 14339-14348.

[167] Wang J, He F, Chen L, Li Q, Jin S, Zheng H, et al. Resveratrol inhibits pulmonary fibrosis by regulating miR-21 through MAPK/AP-1 pathways. Biomed. Pharmacother. 2018, 105, 37-44.

[168] Sun NN, Yu CH, Pan MX, Zhang Y, Zheng BJ, Yang QJ, et al.Mir-21 Mediates the Inhibitory Effect of Ang (1-7) on AngII-induced NLRP3 Inflammasome Activation by Targeting Spry1 in lung fibroblasts. Sci. Rep. 2017, 7, 14369.

[169] Wei P, Xie Y, Abel PW, Huang Y, Ma Q, Li L, et al. Transforming growth factor (TGF)-β1-induced miR-133a inhibits myofibroblast differentiation and pulmonary fibrosis. Cell. Death Dis. 2019, 10, 670.

[170] Zhang JX, Lu J, Xie H, Wang DP, Ni HE, Zhu Y, et al. circHIPK3 regulates lung fibroblast-to-myofibroblast transition by functioning as a competing endogenous RNA. Cell. Death Dis. 2019, 10, 182.

[171] Zhang X, Chen Q, Song H, Jiang W, Xie S, Huang J, et al. MicroRNA-375 prevents TGF-β-dependent transdifferentiation of lung fibroblasts via the MAP2K6/P38 pathway. Mol. Med. Rep. 2020, 22, 1803-1810.

[172] Cui X, Sun X, Lu F, Jiang X. Baicalein represses TGF-beta1-induced fibroblast differentiation through the inhibition of miR-21. Toxicol. Appl. Pharmacol. 2018, 358, 35-42.

[173] Wang P, Xiao T, Li J, Wang D, Sun J, Cheng C, et al. miR-21 in EVs from pulmonary epithelial cells promotes myofibroblast differentiation via glycolysis in arsenic-induced pulmonary fibrosis. Environ. Pollut. 2021, 286, 117259.

[174] Cui H, Banerjee S, Xie N, Ge J, Liu RM, Matalon S, et al. MicroRNA-27a-3p Is a Negative Regulator of Lung Fibrosis by Targeting Myofibroblast Differentiation. Am. J. Respir. Cell. Mol. Biol. 2016, 54, 843-852.

[175] Yan L, Su Y, Hsia I, Xu Y, Vincent-Chong VK, Mojica W, et al. Delivery of anti-microRNA-21 by lung-targeted liposomes for pulmonary fibrosis treatment. Mol. Ther. Nucleic Acids 2023, 32, 36-47.

[176] Chen T, Guo Y, Wang J, Ai L, Ma L, He W, et al. LncRNA CTD-2528L19.6 prevents the progression of IPF by alleviating fibroblast activation. Cell. Death Dis. 2021, 12, 600.

[177] Yang Y, Tai W, Lu N, Li T, Liu Y, Wu W, et al.lncRNA ZFAS1 promotes lung fibroblast-to-myofibroblast transition and ferroptosis via functioning as a ceRNA through miR-150-5p/SLC38A1 axis. Aging 2020, 12, 9085-9102.

[178] Zhang J, Wang H, Chen H, Li H, Xu P, Liu B, et al. ATF3 -activated accelerating effect of LINC00941/lncIAPF on fibroblast-to-myofibroblast differentiation by blocking autophagy depending on ELAVL1/HuR in pulmonary fibrosis. Autophagy 2022, 18, 2636-2655.

[179] Zhang L, Chi X, Luo W, Yu S, Zhang J, Guo Y, et al. Lung myofibroblast transition and fibrosis is regulated by circ0044226. Int. J. Biochem. Cell. Biol. 2020, 118, 105660.

[180] Lee JU, Son JH, Shim EY, Cheong HS, Shin SW, Shin HD, et al. Global DNA Methylation Pattern of Fibroblasts in Idiopathic Pulmonary Fibrosis. DNA Cell. Biol. 2019, 38, 905-914.

[181] Huang SK, Scruggs AM, McEachin RC, White ES, Peters-Golden M. Lung fibroblasts from patients with idiopathic pulmonary fibrosis exhibit genome-wide differences in DNA methylation compared to fibroblasts from nonfibrotic lung. PLoS ONE 2014, 9, e107055.

[182] Scruggs AM, Koh HB, Tripathi P, Leeper NJ, White ES, Huang SK. Loss of CDKN2B Promotes Fibrosis via Increased Fibroblast Differentiation Rather Than Proliferation. Am. J. Respir. Cell. Mol. Biol. 2018, 59, 200-214.

[183] Neveu WA, Mills ST, Staitieh BS, Sueblinvong V. TGF-β1 epigenetically modifies Thy-1 expression in primary lung fibroblasts. Am. J. Physiol. Cell. Physiol. 2015, 309, C616-C626.

[184] Wang Y, Zhang L, Huang T, Wu GR, Zhou Q, Wang FX, et al. The methyl-CpG-binding domain 2 facilitates pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation. Eur. Respir. J. 2022, 60, 3.

[185] Xiang Z, Zhou Q, Hu M, Sanders YY. MeCP2 epigenetically regulates alpha-smooth muscle actin in human lung fibroblasts. J. Cell. Biochem. 2020, 121, 3616-3625.

[186] Korfei M, Skwarna S, Henneke I, MacKenzie B, Klymenko O, Saito S, et al. Aberrant expression and activity of histone deacetylases in sporadic idiopathic pulmonary fibrosis. Thorax 2015, 70, 1022-1032.

[187] Huang SK, Scruggs AM, Donaghy J, Horowitz JC, Zaslona Z, Przybranowski S, et al. Histone modifications are responsible for decreased Fas expression and apoptosis resistance in fibrotic lung fibroblasts. Cell. Death Dis. 2013, 4, e621.

[188] Sanders YY, Hagood JS, Liu H, Zhang W, Ambalavanan N, Thannickal VJ. Histone deacetylase inhibition promotes fibroblast apoptosis and ameliorates pulmonary fibrosis in mice. Eur. Respir. J. 2014, 43, 1448-1458.

[189] Jones DL, Haak AJ, Caporarello N, Choi KM, Ye Z, Yan H, et al. TGFβ-induced fibroblast activation requires persistent and targeted HDAC-mediated gene repression. J. Cell. Sci. 2019, 132, jcs233486.

[190] Saito S, Zhuang Y, Suzuki T, Ota Y, Bateman ME, Alkhatib AL, et al. HDAC8 inhibition ameliorates pulmonary fibrosis. Am. J. Physiol. Lung Cell. Mol. Physiol. 2019, 316, L175-L186.

[191] Selman M, Pardo A. Role of epithelial cells in idiopathic pulmonary fibrosis: From innocent targets to serial killers. Proc. Am. Thorac. Soc. 2006, 3, 364-372.

[192] Enomoto Y, Katsura H, Fujimura T, Ogata A, Baba S, Yamaoka A, et al. Autocrine TGF-beta-positive feedback in profibrotic AT2-lineage cells plays a crucial role in non-inflammatory lung fibrogenesis. Nat. Commun. 2023, 14, 4956.

[193] Antoniades HN, Bravo MA, Avila RE, Galanopoulos T, Neville-Golden J, Maxwell M, et al. Platelet-derived growth factor in idiopathic pulmonary fibrosis. J. Clin. Investig. 1990, 86, 1055-1064.

[194] Prefontaine A, Calderone A, Dupuis J. Role of endothelin receptors on basal and endothelin-1-stimulated lung myofibroblast proliferation. Can. J. Physiol. Pharmacol. 2008, 86, 337-342.

[195] Swigris JJ, Brown KK. The role of endothelin-1 in the pathogenesis of idiopathic pulmonary fibrosis. BioDrugs 2010, 24, 49-54.

[196] Effendi WI, Nagano T. Connective Tissue Growth Factor in Idiopathic Pulmonary Fibrosis: Breaking the Bridge. Int. J. Mol. Sci. 2022, 23, 6064.

[197] Hewlett JC, Kropski JA, Blackwell TS. Idiopathic pulmonary fibrosis: Epithelial-mesenchymal interactions and emerging therapeutic targets. Matrix. Biol. 2018, 71-72, 112-127.

[198] Dong J, Ma Q. Osteopontin enhances multi-walled carbon nanotube-triggered lung fibrosis by promoting TGF-beta1 activation and myofibroblast differentiation. Part. Fibre. Toxicol. 2017, 14, 18.

[199] Sabo-Attwood T, Ramos-Nino ME, Eugenia-Ariza M, Macpherson MB, Butnor KJ, Vacek PC, et al. Osteopontin modulates inflammation, mucin production, and gene expression signatures after inhalation of asbestos in a murine model of fibrosis. Am. J. Pathol. 2011, 178, 1975-1985.

[200] Yang J, Pan X, Xu M, Li Y, Liang C, Liu L, et al. Downregulation of HMGCS2 mediated AECIIs lipid metabolic alteration promotes pulmonary fibrosis by activating fibroblasts. Respir. Res. 2024, 25, 176.

[201] Yang X, Sun W, Jing X, Zhang Q, Huang H, Xu Z. C/EBP homologous protein promotes Sonic Hedgehog secretion from type II alveolar epithelial cells and activates Hedgehog signaling pathway of fibroblast in pulmonary fibrosis. Respir. Res. 2022, 23, 86.

[202] Bai J, Deng J, Han Z, Cui Y, He R, Gu Y, et al.CircRNA_0026344 via exosomal miR-21 regulation of Smad7 is involved in aberrant cross-talk of epithelium-fibroblasts during cigarette smoke-induced pulmonary fibrosis. Toxicol. Lett. 2021, 347, 58-66.

[203] Wang P, Xie D, Xiao T, Cheng C, Wang D, Sun J, et al. H3K18 lactylation promotes the progression of arsenite-related idiopathic pulmonary fibrosis via YTHDF1/m6A/NREP. J. Hazard. Mater. 2024, 461, 132582.

[204] Waghray M, Cui Z, Horowitz JC, Subramanian IM, Martinez FJ, Toews GB, et al.Hydrogen peroxide is a diffusible paracrine signal for the induction of epithelial cell death by activated myofibroblasts. FASEB J. 2005, 19, 854-856.

[205] Xu SW, Howat SL, Renzoni EA, Holmes A, Pearson JD, Dashwood MR, et al. Endothelin-1 induces expression of matrix-associated genes in lung fibroblasts through MEK/ERK. J. Biol. Chem. 2004, 279, 23098-23103.

[206] Kulasekaran P, Scavone CA, Rogers DS, Arenberg DA, Thannickal VJ, Horowitz JC. Endothelin-1 and transforming growth factor-beta1 independently induce fibroblast resistance to apoptosis via AKT activation. Am. J. Respir. Cell. Mol. Biol. 2009, 41, 484-493.

[207] Liu Q, Niu Y, Pei Z, Yang Y, Xie Y, Wang M, et al. Gas6-Axl signal promotes indoor VOCs exposure-induced pulmonary fibrosis via pulmonary microvascular endothelial cells-fibroblasts cross-talk. J. Hazard. Mater. 2024, 474, 134786.

[208] Cao Z, Lis R, Ginsberg M, Chavez D, Shido K, Rabbany SY, et al. Targeting of the pulmonary capillary vascular niche promotes lung alveolar repair and ameliorates fibrosis. Nat. Med. 2016, 22, 154-162.

[209] Caporarello N, Lee J, Pham TX, Jones DL, Guan J, Link PA, et al. Dysfunctional ERG signaling drives pulmonary vascular aging and persistent fibrosis. Nat. Commun. 2022, 13, 4170.

[210] Nie R, Zhang QY, Feng ZY, Huang K, Zou CY, Fan MH, et al. Hydrogel-based immunoregulation of macrophages for tissue repair and regeneration. Int. J. Biol. Macromol. 2024, 268, 131643.

[211] Young LR, Gulleman PM, Short CW, Tanjore H, Sherrill T, Qi A, et al. Epithelial-macrophage interactions determine pulmonary fibrosis susceptibility in Hermansky-Pudlak syndrome. JCI Insight 2016, 1, e88947.

[212] Hou J, Shi J, Chen L, Lv Z, Chen X, Cao H, et al. M2 macrophages promote myofibroblast differentiation of LR-MSCs and are associated with pulmonary fibrogenesis. Cell. Commun. Signal. 2018, 16, 89.

[213] Libório-Ramos S, Barbosa-Matos C, Fernandes R, Borges-Pereira C, Costa S. Interstitial Macrophages Lead Early Stages of Bleomycin-Induced Lung Fibrosis and Induce Fibroblasts Activation. Cells 2023, 12, 402.

[214] Prasse A, Pechkovsky DV, Toews GB, Jungraithmayr W, Kollert F, Goldmann T, et al.A vicious circle of alveolar macrophages and fibroblasts perpetuates pulmonary fibrosis via CCL18. Am. J. Respir. Crit. Care. Med. 2006, 173, 781-792.

[215] Luzina IG, Tsymbalyuk N, Choi J, Hasday JD, Atamas SP. CCL18-stimulated upregulation of collagen production in lung fibroblasts requires Sp1 signaling and basal Smad3 activity. J. Cell. Physiol. 2006, 206, 221-228.

[216] You Y, Yuan H, Min H, Li C, Chen J. Fibroblast-derived CXCL14 aggravates crystalline silica-induced pulmonary fibrosis by mediating polarization and recruitment of interstitial macrophages. J. Hazard. Mater. 2023, 460, 132489.

[217] Xia J, Wang D, Guo W, Pei Y, Zhang L, Bao L, et al. Exposure to micron-grade silica particles triggers pulmonary fibrosis through cell-to-cell delivery of exosomal miR-107. Int. J. Biol. Macromol. 2024, 266, 131058.

[218] Niu Z, Wang L, Qin X, Ye Z, Xie B, Hu Y. Macrophage derived miR-7219-3p-containing exosomes mediate fibroblast trans-differentiation by targeting SPRY1 in silicosis. Toxicology 2022, 479, 153310.

[219] Ding M, Zhang C, Wang W, Wang P, Pei Y, Wang N, et al. Silica-exposed macrophages-secreted exosomal miR125a-5p induces Th1/Th2 and Treg/Th17 cell imbalance and promotes fibroblast transdifferentiation. Ecotoxicol. Environ. Saf. 2023, 267, 115647.

[220] Wang D, Hao C, Zhang L, Zhang J, Liu S, Li Y, et al. Exosomal miR-125a-5p derived from silica-exposed macrophages induces fibroblast transdifferentiation. Ecotoxicol. Environ. Saf. 2020, 192, 110253.

[221] Reyfman PA, Walter JM, Joshi N, Anekalla KR, McQuattie-Pimentel AC, Chiu S, et al. Single-Cell Transcriptomic Analysis of Human Lung Provides Insights into the Pathobiology of Pulmonary Fibrosis. Am. J. Respir. Crit. Care. Med. 2019, 199, 1517-1536.

[222] Wang J, Jiang M, Xiong A, Zhang L, Luo L, Liu Y, et al. Integrated analysis of single-cell and bulk RNA sequencing reveals pro-fibrotic PLA2G7(high) macrophages in pulmonary fibrosis. Pharmacol. Res. 2022, 182, 106286.

[223] Aran D, Looney AP, Liu L, Wu E, Fong V, Hsu A, et al. Reference-based analysis of lung single-cell sequencing reveals a transitional profibrotic macrophage. Nat. Immunol. 2019, 20, 163-172.

[224] Cui H, Xie N, Banerjee S, Ge J, Jiang D, Dey T, et al. Lung Myofibroblasts Promote Macrophage Profibrotic Activity through Lactate-induced Histone Lactylation. Am. J. Respir. Cell. Mol. Biol. 2021, 64, 115-125.

[225] Deng Z, Fan T, Xiao C, Tian H, Zheng Y, Li C, et al.TGF-beta signaling in health, disease, and therapeutics. Signal. Transduct. Target. Ther. 2024, 9, 61.

[226] Richeldi L, du Bois RM, Raghu G, Azuma A, Brown KK, Costabel U, et al. Efficacy and safety of nintedanib in idiopathic pulmonary fibrosis. N. Engl. J. Med. 2014, 370, 2071-2082.

[227] King TE Jr., Bradford WZ, Castro-Bernardini S, Fagan EA, Glaspole I, Glassberg MK, et al. A phase 3 trial of pirfenidone in patients with idiopathic pulmonary fibrosis. N. Engl. J. Med. 2014, 370, 2083-2092.

[228] Chen C-Y, Tung H-Y, Tseng Y-F, Huang J-S, Shi L-S, Ye Y-L. Verbascoside and isoverbascoside ameliorate transforming growth factor β1-induced collagen expression by lung fibroblasts through Smad/non-Smad signaling pathways. Life Sci. 2022, 308, 120950.

[229] Cao H, Chen X, Hou J, Wang C, Xiang Z, Shen Y, et al. The Shh/Gli signaling cascade regulates myofibroblastic activation of lung-resident mesenchymal stem cells via the modulation of Wnt10a expression during pulmonary fibrogenesis. Lab. Investig. 2020, 100, 363-377.

[230] Romero Y, Bueno M, Ramirez R, Álvarez D, Sembrat JC, Goncharova EA, et al. mTORC1 activation decreases autophagy in aging and idiopathic pulmonary fibrosis and contributes to apoptosis resistance in IPF fibroblasts. Aging Cell. 2016, 15, 1103-1112.

[231] Yu JZ, Wen J, Ying Y, Yin W, Zhang SQ, Pang WL, et al. Astragaloside trigger autophagy: Implication a potential therapeutic strategy for pulmonary fibrosis. Biomed. Pharmacother. 2022, 154, 113603.

[232] Peng J, Xiao X, Li S, Lyu X, Gong H, Tan S, et al. Aspirin alleviates pulmonary fibrosis through PI3K/AKT/mTOR-mediated autophagy pathway. Exp. Gerontol. 2023, 172, 112085.

[233] He J, Peng H, Wang M, Liu Y, Guo X, Wang B, et al. Isoliquiritigenin inhibits TGF-β1-induced fibrogenesis through activating autophagy via PI3K/AKT/mTOR pathway in MRC-5 cells. Acta Biochim. Et. Biophys. Sin. 2020, 52, 810-820.

[234] Qi J, Wu Y, Guo Z, Zhu S, Xiong J, Hu F, et al. Fibroblast growth factor 21 alleviates idiopathic pulmonary fibrosis by inhibiting PI3K-AKT-mTOR signaling and stimulating autophagy. Int. J. Biol. Macromol. 2024, 273, 132896.

[235] Raj K, Mufti GJ. Azacytidine (Vidaza(R)) in the treatment of myelodysplastic syndromes. Ther. Clin. Risk. Manag. 2006, 2, 377-388.

[236] Robinson CM, Neary R, Levendale A, Watson CJ, Baugh JA. Hypoxia-induced DNA hypermethylation in human pulmonary fibroblasts is associated with Thy-1 promoter methylation and the development of a pro-fibrotic phenotype. Respir. Res. 2012, 13, 74.

[237] Huan C, Yang T, Liang J, Xie T, Cheng L, Liu N, et al. Methylation-mediated BMPER expression in fibroblast activation in vitro and lung fibrosis in mice in vivo. Sci. Rep. 2015, 5, 14910.

[238] Wei A, Gao Q, Chen F, Zhu X, Chen X, Zhang L, et al. Inhibition of DNA methylation de-represses peroxisome proliferator-activated receptor-γ and attenuates pulmonary fibrosis. Br. J. Pharmacol. 2022, 179, 1304-1318.

[239] Korfei M, Stelmaszek D, MacKenzie B, Skwarna S, Chillappagari S, Bach AC, et al. Comparison of the antifibrotic effects of the pan-histone deacetylase-inhibitor panobinostat versus the IPF-drug pirfenidone in fibroblasts from patients with idiopathic pulmonary fibrosis. PLoS ONE 2018, 13, e0207915.

[240] Yu WC, Yeh TY, Ye CH, Chong PCT, Ho YH, So DK, et al. Discovery of HDAC6, HDAC8, and 6/8 Inhibitors and Development of Cell-Based Drug Screening Models for the Treatment of TGF-β-Induced Idiopathic Pulmonary Fibrosis. J. Med. Chem. 2023, 66, 10528-10557.

[241] Campiani G, Cavella C, Osko JD, Brindisi M, Relitti N, Brogi S, et al. Harnessing the Role of HDAC6 in Idiopathic Pulmonary Fibrosis: Design, Synthesis, Structural Analysis, and Biological Evaluation of Potent Inhibitors. J. Med. Chem. 2021, 64, 9960-9988.

[242] Valand A, Rajasekar P, Wain LV, Clifford RL. Interplay between genetics and epigenetics in lung fibrosis. Int. J. Biochem. Cell. Biol. 2025, 180, 106739.

[243] Liu CH, Lee HS, Liou JP, Hua HS, Cheng WH, Yuliani FS, et al. MPT0E028, a novel pan-HDAC inhibitor, prevents pulmonary fibrosis through inhibition of TGF-beta-induced CTGF expression in human lung fibroblasts: Involvement of MKP-1 activation. Eur. J. Pharmacol. 2024, 977, 176711.

[244] Li Y, Yang H, Zhao X, Zhao X, Quan J, Wang L, et al. Discovery of novel pyrrolo [2,1-c][1,4]benzodiazepine-3,11-dione (PBD) derivatives as selective HDAC6 inhibitors for the efficient treatment of idiopathic pulmonary fibrosis (IPF) in vitro and in vivo. Eur. J. Med. Chem. 2024, 275, 116608.

[245] Gerokonstantis DT, Mantzourani C, Gkikas D, Wu KC, Hoang HN, Triandafillidi I, et al. N-(2-Aminophenyl)-benzamide Inhibitors of Class I HDAC Enzymes with Antiproliferative and Antifibrotic Activity. J. Med. Chem. 2023, 66, 14357-14376.