Intervertebral disc degeneration (IVDD) is a primary contributor to low back pain, posing significant social and economic burdens. Increasing evidence shows that obesity contributes to IVDD, yet the underlying mechanisms remain elusive. Here, we firstly revealed a causal correlation between obesity and IVDD via a two-sample mendelian randomization analysis and identified fatty acid-binding protein 4 (FABP4) as the potential regulator to associate IVDD and obesity. Elevated FABP4 expression promoted extracellular matrix (ECM) disequilibrium and angiogenesis to exacerbate IVDD progression. Genetically knocking out or pharmacologically inhibiting FABP4 in high-fat diet-induced mice alleviated IVDD. Mechanistically, obesity activated the mammalian target of rapamycin complex 1 (mTORC1), which upregulated FABP4 expression, leading to the accumulation of advanced glycation end-products (AGEs) in intervertebral disc tissue. AGEs further activated the NF-κB signalling pathway, exacerbating ECM degradation and neovascularization. Conversely, rapamycin-mediated inhibition of mTORC1 suppressed FABP4 expression in nucleus pulposus cells (NPCs), alleviating IVDD in vivo. Collectively, our findings reveal a critical role of the obesity-induced mTORC1-FABP4 axis in ECM degradation and angiogenesis during IVDD progression. Targeting FABP4 may represent a promising therapeutic strategy for IVDD in obese individuals.

The keystone pathogen Porphyromonas gingivalis (P.g.) is responsible for cementum resorption in periodontitis; however, the mechanism involved in it remains unclear. Sirtuin 3 (Sirt3) is a NAD⁺-dependent protein deacetylase contributing to mitochondrial homeostasis and various cell functions. In this study, the expression of Sirt3 in cementoblasts was found to be increased during cementoblast mineralisation and cementum development, while it decreased gradually under P.g. infection in a multiplicity of infection-dependent manner. Compared with wild type mice, the Sirt3 knockout mice showed less cellular cementum and lower mineralisation capacity with decreased expression of Runx2 and OCN in cementoblasts. Sirt3 inhibition by 3-TYP or Sirt3 silencing by lentivirus infection both confirmed the impaired cementogenesis. Conversely, honokiol (HKL) was simulated to bind Sirt3 and was applied to activate Sirt3 in cementoblasts. HKL-mediated Sirt3 activation facilitated cementoblast mineralisation and rescued P.g.-suppressed cementoblast mineralisation markedly. Superoxide dismutase 2 (SOD2), the downstream molecule of Sirt3, showed a similar expression pattern to Sirt3 under different conditions. Silencing of SOD2 was demonstrated to restrain cementoblast mineralisation. The pan acetylation was detected to decrease under Sirt3-upregulating conditions and increase under Sirt3-downregulating conditions. The binding of Sirt3 and SOD2 in cementoblasts was also verified. Furthermore, SOD2 acetylation and specific SOD2-K68 acetylation were found to be upregulated under P.g. or Sirt3 silencing conditions and downregulated by HKL stimulation. Moreover, K68Q mutation simulating acetylation decreased cementoblast mineralisation, while K68R mutation simulating deacetylation increased it. Altogether, Sirt3 deacetylates SOD2 via K68 to orchestrate P.g.-perturbed cementogenesis, and HKL is a Sirt3-targeted treatment candidate.

Diminished ovarian reserve (DOR) is a pathological condition characterised by reduced ovarian function, which refers to the decreased quality and quantity of oocytes, potentially causing female infertility and various health issues. Follicular fluid (FF) serves as the microenvironment for follicular development and oocyte maturation, gaining an in-depth understanding of the metabolic state of FF will help us uncover the key biological processes involved in ovarian aging, while the specific underlying pathogenic mechanisms are not fully understood. In this study, we utilised pseudotargeted metabolomic analysis of FF to reveal the glycerophospholipid metabolism dysfunction mediated by GPD1L in DOR patients. We also found that GPD1L was downregulated in granulosa cells (GCs) of DOR patients, resulting in increased cell apoptosis and mitochondrial dysfunction. Moreover, our results demonstrated that the downregulated expression of GPD1L could induce follicular atresia and impair oocyte quality in mouse ovaries. Altogether, our research suggested that GPD1L in GCs and the key metabolites in the glycerophospholipid metabolism pathway could potentially act as novel biomarkers of DOR diagnosis, paving the way for a new theoretical basis for understanding the pathogenesis of DOR.

Uterine fibroids (UFs) are the most common benign gynecologic tumours affecting women of reproductive age. This study aims to deepen the understanding of UFs complex aetiology through harnessing the power of 3D organoid models derived from human myometrial stem cells to emulate the in vivo behaviour of these tumours. Isolated SCs were cultured over 7 days under a defined culture system. Immunohistochemistry, Immunofluorescence, organoid stiffness, RNA Sequencing was conducted, and differential gene expression was assessed using RT-PCR. The derived organoids exhibited diverse populations of cells, including stem cells, smooth muscle, and fibroblasts. Excessive ECM deposition was shown via Collagen and Fibronectin expression. We confirmed that our organoids expressed oestrogen receptor in a pattern similar to that in their corresponding tissue, as well as responded to steroid hormone. Interestingly, we revealed significant racial disparities in ECM accumulation within organoids derived from different racial groups. This augmented ECM deposition is theorised to enhance tissue stiffness, as assessed using Young's modulus. Additionally, our research demonstrated significant decreases in fibrotic markers upon treatment with Vitamin D3 and Doxercalciferol. Furthermore, the pro-fibroid effects of environmental phthalates further elucidate the potential factors contributing to UF pathology. The 3D organoid model can serve as a robust platform to study the underlying molecular mechanisms of UFs, besides offering invaluable insights for potential therapeutic interventions.

Gene-edited (GE) pig-to-human xenotransplantation continues to make breakthroughs, but which kind of gene combination is suitable for organ-specific transplantation remains unclear. In this study, we utilised CRISPR/Cas9 gene editing technology, PiggyBac transposon system, and serial somatic cell cloning technology to develop GTKO/CMAHKO/β4GalNT2KO/hCD46/hCD55/hCD59/hCD39/hTBM 8 gene-edited cloned (GEC) donor pigs and performed pig-to-non-human primate (NHP) transplantation to evaluate the effectiveness of these GEC pigs. The 8-GEC pigs were obtained by recloning with a 33-day-old 8-GEC fetus with O blood type, which was generated after cell transfection, screening of cell colonies, and somatic cell cloning. Molecular identification at DNA, mRNA, and protein levels confirmed successful 8-gene editing. Three copies of transgenes were identified by droplet digital polymerase chain reaction and whole genome sequencing, which were inserted into the introns of pig RFTN1 and MYO10 genes, as well as the intergenic region between PRLR and LOC110257300 genes of these 8-GEC pigs. The 8-GEC pigs also exhibited the ability of germline transmission when mated with our previously generated 4-GEC male pigs. Moreover, antigen–antibody binding assay and complement-dependent cytotoxicity assay demonstrated that 8-gene editing effectively reduced the immune incompatibility and kidney xenograft from 8-GEC pigs survived for 15 and 17 days in two NHPs, respectively. Postoperatively, the recipient serum antibodies IgA, IgG and IgM, complements C3 and C4, coagulation indicators PT, APTT, TT and FIB, as well as most electrolytes and liver function indicators remained relatively stable. Serum creatinine was normal within 10 days post operation. However, the kidney xenograft developed active antibody-mediated rejection at necropsy, characterised by the deposition of antibodies IgG and IgM, as well as complements C4d, C3c and C5b-C9, infiltration of CD68⁺ macrophages, and micro-thrombotic embolism of glomerular capillaries, etc. In conclusion, we successfully developed fertile 8-GEC pigs, which effectively alleviated immune rejection and exerted life-supporting kidney function in the recipients.

The treatment of postmenopausal osteoporosis (OP) presents a multifaceted challenge. Nonetheless, emerging research indicates a significant association between the N6-methyladenosine (m6A) methylase METTL3 and osteogenesis in OP. To investigate Mettl3's impact on osteogenic potential and the underlying molecular mechanisms, an OP rat model was established via ovariectomy (OVX). Osteoporotic adipose-derived stem cells (OP-ASCs) were then isolated. Results indicated a significant downregulation of Mettl3 expression in OP-ASCs. Subsequently, OP-ASCs were transfected with overexpressed Mettl3 lentivirus and treated for Dickkopf-related protein-1 (DKK1). Overexpression of the Mettl3 gene led to increased levels of osteogenic factors. DKK1 attenuated osteoblastic differentiation capacity in the Mettl3 overexpression group by inhibiting the Wnt signalling pathway. Consistent results were observed in vivo experiments. In conclusion, overexpression of Mettl3 promotes osteogenesis in OP-ASCs by activating the Wnt/β-catenin pathway.

This paper discussed the role of AlkB homologue 5 (Alkbh5) in the progression of lipopolysaccharide (LPS)-induced acute lung injury (ALI). LPS-induced ALI models were established in Alkbh5 knockout (KO) and knock-in (KI) mice. The m6A levels in lung tissues were analysed using m6A dot assays. The lung injury was analysed by determining ALI-related markers and histological staining. Mouse MLE12 cells were exposed to LPS for in vitro experiments, and the influence of Alkbh5 on cell viability, apoptosis and reactive oxygen species (ROS) production was analysed. RNA-seq analysis was performed to analyse gene changes upon Alkbh5 deficiency. Functions of the Alkbh5-C-C motif chemokine ligand 1 (Ccl1) cascade in ALI were further verified using the Alkbh5 antagonist DDO-2728 and a recombinant protein of Ccl1 (mCcl1). Alkbh5 was upregulated in lung tissues following LPS exposure. Alkbh5 knockout in mice mitigated LPS-induced lung injury, as indicated by reduced serum levels of lung injury markers and reduced immune cell infiltration, fibrosis and apoptosis. Conversely, Alkbh5 overexpression in mice resulted in reverse trends. In vitro, Alkbh5 knockdown in MLE12 cells enhanced cell viability while reducing cell apoptosis and ROS production. Mechanistically, Alkbh5 was found to bind to and destabilise Ccl1 mRNA, leading to increased Treg recruitment. Treatment with DDO-2728 or mCcl1 in mice increased Treg infiltration, thus improving lung tissue pathology and reducing lung injury. This study suggests that Alkbh5 is implicated in ALI progression by reducing Ccl1-mediated Treg recruitment, making it a promising target for ALI management.

Liver transplantation is currently the sole definitive treatment option for end-stage liver failure. However, a significant shortage of donors prevails due to high clinical demands. Recently, human liver organoids have shown significant potential in regenerative medicine for liver diseases. Nevertheless, current static cultures of organoids grown in well-plates heavily rely on extracellular matrix hydrogels (Matrigel), thereby limiting both the scalability and quantity of organoid culture. In this study, we present a groundbreaking culture mode that eliminates all reliance on extracellular matrix hydrogels, enabling the successful preparation of functional human liver ductal organoids (LDOs) based on the cell suspension culture mode in a mechanically stirred bioreactor. Initially, the developed suspension culture in a 6-well plate without matrigel was proven to support robust growth of liver ductal organoids with an average size 2.6 times larger than those obtained in static culture, and with a high organoid survival rate exceeding 90%. Also, the transcriptome profile reveals that suspension culture activates the phosphatidylinositol 3-kinase (PI3K) signalling pathway through mechanical signal transduction, thereby promoting hepatobiliary characteristics. Then, a controllable and scalable bioprocess for liver ductal organoid culture was developed and successfully scaled up to a 50 mL flask bioreactor with a working volume of 15 mL. Finally, animal experiments indicated that the transplantation of liver ductal organoids harvested from suspension culture can effectively alleviate liver injury and inflammation, demonstrating the feasibility of large-scale production of liver ductal organoids cultivated in suspension culture with an improved extracellular matrix environment.

Lactate is not only a byproduct of glycolysis, but is also considered an energy source, gluconeogenic precursor, signalling molecule and protein modifier during the process of cellular metabolism. The discovery of lactylation reveals the multifaceted functions of lactate in cellular metabolism and opens new avenues for lactate-related research. Both lactate and lactylation have been implicated in regulating numerous biological processes, including tumour progression, ischemic–hypoxic injury, neurodevelopment and immune-related inflammation. The kidney plays a crucial role in regulating lactate metabolism, influencing lactate levels while also being regulated by lactate. Previous studies have demonstrated the importance of lactate in the pathogenesis of acute kidney injury (AKI) and chronic kidney disease (CKD). This review explores the role of lactate and lactylation in these diseases, comparing the function and metabolic mechanisms of lactate in normal and diseased kidneys from the perspective of lactylation. The key regulatory roles of lactylation in different organs, multiple systems, various pathological states and underlying mechanisms in AKI-to-CKD progression are summarised. Moreover, potential therapeutic targets and future research directions for lactate and lactylation across multiple kidney diseases are identified.

Natural Killer (NK) cells have shown promising prospects in ‘off-the-shelf’ cell therapy, particularly the NK-92 cell line, which can serve as a foundation for the next generation of universal chimeric antigen receptor (CAR)-engineered NK products. A key strategy for generating universal cellular products is the elimination of the beta-2-microglobulin (B2M) gene, which encodes a component of MHC class I molecules (MHC-I) that plays a role in the presentation of foreign antigens and in the ‘licensing’ or ‘education’ of NK cells. To functionally study the impacts of MHC-I deficiency on NK-92, we generated a B2M knockout (KO) NK-92MI (B-92) cell line and compared the multidimensional properties of B2M KO and wild-type NK-92MI cells in terms of biological phenotypes, effector functions, and transcriptomic signatures. We observed a decrease in activating receptors, cytokine production, and cytotoxicity in B-92 cells. Further analysis of signalling events revealed that the upregulated expression and phosphorylation of SHP-1 in B-92 cells inhibited the phosphorylation levels of STAT3 and ERK, thereby affecting their killing function. By knocking out SHP-1 (PTPN6), we partially restored the cytotoxic function of B-92 cells. Notably, we also found that CAR modification can overcome the hyporesponsiveness of B-92 cells. These findings will facilitate further exploration in the development of NK cell-based products.

Natural killer (NK) cells are critical regulators of immune processes during early pregnancy, playing a key role in maintaining maternal-foetal immune tolerance and supporting successful implantation. In particular, uterine NK cells, a specialised subset of NK cells, facilitate trophoblast invasion, spiral artery remodelling and placental establishment. Dysregulation of NK cell activity, however, has been implicated in pregnancy complications, notably recurrent spontaneous abortion (RSA) and recurrent implantation failure (RIF). Aberrant NK cell functions, such as heightened cytotoxicity or defective immune signalling, can disrupt the balance between immune tolerance and response, leading to impaired placental development, reduced trophoblast activity and compromised uteroplacental blood flow. This review examines the role of NK cells in early pregnancy, emphasising their contributions to immune modulation and placentation. It also investigates the mechanisms by which NK cell dysfunction contributes to RSA and RIF, and explores therapeutic strategies aimed at restoring NK cell balance to improve pregnancy outcomes. A deeper understanding of NK cell interactions during early pregnancy may provide critical insights into the pathogenesis of pregnancy failure and facilitate targeted immunotherapeutic approaches.

Intervertebral disc (IVD) degeneration is an age-related problem triggering chronic spinal issues, such as low back pain and IVD herniation. Standard surgical treatment for such spinal issues is the removal of the degenerated or herniated IVD and fusion of adjacent vertebrae to stabilise the joint and locally decompress the spinal cord and/or nerve roots to relieve pain. However, a key challenge of current surgical strategies is the increasing risk of adjacent segment degeneration due to the disruption of native biomechanics of the functional spinal unit, dominated by the loss of the IVD. In the past two decades, research has focused on developing a number of bioengineering approaches to repair and regenerate the IVD; in particular, tissue engineering of the IVD, using bioscaffolds and stem cells represents a promising area. This review highlights the current tissue engineering approaches utilising biomaterials, animal models and cell sources for IVD regeneration and discusses future opportunities.

Aging is characterised by progressive structural and functional changes in the liver, with the extracellular matrix (ECM) playing a key role in modulating these changes. Our study presents a comprehensive proteomic analysis of the liver ECM across different age stages, uncovering significant age-related changes. Through the identification of 158 ECM proteins in decellularised rat liver scaffolds, we reveal the intricate relationship between ECM composition and liver maturation, as well as the decrease in regenerative capacity. Lumican was identified as a critical regulator with heightened expression in neonatal livers, which is associated with enhanced hepatocyte proliferation and maintenance of stem cell characteristics. Temporal expression analysis distinguished four distinct clusters of ECM proteins, each reflecting the liver's functional evolution from early development to old age. Early developmental stages were marked by proteins essential for liver growth, while adulthood was characterised by a robust ECM supporting metabolic functions. Middle age showed a regulatory shift towards protease balance, and later life was associated with haemostasis-related processes. Our findings underscore the multifaceted role of the ECM in liver health and aging, offering potential opportunities for therapeutic intervention to counteract age-induced liver dysfunction. This study provides a foundational understanding of ECM dynamics in liver aging and sets the stage for the development of innovative strategies to mitigate the effects of age-related liver decline.