The skeleton is an important structural and metabolic organ in human body, while aging is the physiological basis for degenerative skeletal diseases. China has the largest aging population in the world and faces great challenges in preventing and managing diseases related to skeletal aging. To address these challenges, the Aging China Biomarkers Consortium (ABC) has reached an expert consensus on biomarkers of skeletal aging by synthesizing the literature and insights from scientists and clinicians. The consensus provides a comprehensive assessment of biomarkers associated with skeletal aging and proposes a systematic framework that categorizes biomarkers into three dimensions, namely, functional, structural, and humoral dimensions. Within each dimension, the ABC recommended clinical and evidential research-based biomarkers for physiological aging and degenerative pathologies of the skeleton. This expert consensus aims to lay the foundation for future studies to assess the prediction, diagnosis, early warning, and treatment of diseases associated with skeletal aging, with the ultimate goal of improving the skeletal health of elderly populations in China and around the world.
3D bioprinting emerges as a critical tool in biofabricating functional 3D tissue or organ equivalents for regenerative medicine. Bioprinting techniques have been making strides in integrating automation, customization, and digitalization in coping with diverse tissue engineering scenarios. The convergence of robotic arm-based 3D bioprinting techniques, especially in situ 3D bioprinting, is a versatile toolbox in the industrial field, promising for biomedical application and clinical research. In this review, we first introduce conceptualized modalities of robotic arm-based bioprinting from a mechanical perspective, which involves configurative categories of current robot arms regarding conventional bioprinting strategies. Recent advances in robotic arm-based bioprinting in tissue engineering have been summarized in distinct tissues and organs. Ultimately, we systematically discuss relative advantages, disadvantages, challenges, and future perspectives from bench to bedside for biomedical application.
Pharyngeal pouches, which are endodermal outpockets that segment the pharyngeal arches, play a crucial role in the development of craniofacial skeletons in vertebrate embryos. Our previous study successfully identified pharyngeal pouch progenitors (PPPs) in zebrafish embryos and emphasized the significance of BMP2b signaling in their specification. However, the specific mechanism by which these progenitors originate from endodermal cells remains largely unknown. Here we found that the pharmacological activation of Wnt signaling pathway disrupts the emergence of PPPs and subsequently hinders the formation of pharyngeal pouches. Moreover, we have identified the expression of tmem88a and tmem88b (collectively known as tmem88a/b) in PPPs during the early-somite stages. Furthermore, the deficiency of tmem88a/b leads to an excessive accumulation of β-catenin in both the cytoplasm and nucleus of endodermal cells that are intended to differentiate into PPPs. Importantly, suppressing the hyperactivation of Wnt/β-catenin signaling through pharmacological treatment, the defects in PPP specification in tmem88a/b−/− mutants are successfully rescued. In summary, our findings establish a clear connection between the specification of PPPs and the regulation of Wnt signaling mediated by Tmem88. These results underscore the pivotal role of Tmem88 in the development of pharyngeal pouches.
The pathogenesis of several kidney diseases results in the eventual destruction of the renal tubular system, which can progress to end-stage renal disease. Previous studies have demonstrated the involvement of a population of SOX9-positive cells in kidney regeneration and repair process following kidney injury. However, the ability of these cells to autonomously generate kidney organoids has never been investigated. Here, we isolated SOX9+ kidney progenitor cells (KPCs) from both mice and humans and tested their differentiation potential in vitro. The data showed that the human SOX9+ KPC could self-assemble into organoids with kidney-like morphology. We also used single-cell RNA sequencing to characterize the organoid cell populations and identified four distinct types of renal tubular cells. Compared to the induced pluripotent stem cell-derived kidney organoids, KPC demonstrated more tubular differentiation potential but failed to differentiate into glomerular cells. KPC-derived organoid formation involved the expression of genes related to metanephric development and followed a similar mechanism to renal injury repair in acute kidney injury patients. Altogether, our study provided a potentially useful approach to generating kidney tubular organoids for future application.
Glioma stem cells (GSCs) in the hypoxic niches contribute to tumor initiation, progression, and recurrence in glioblastoma (GBM). Metabolic pathways are altered in GSCs under hypoxia, but the mechanism underlying the altered one-carbon metabolism in GSCs by hypoxia is largely unknown. Here, we report that hypoxia induces down-regulation of DHFR as well as up-regulation of MAT2A in GBM tumorsphere cells, and confers them the ability of cell proliferation that is independent of exogenous folate. Importantly, short-term inhibition of the methionine cycle or exposure to the MAT2A inhibitor is sufficient to cripple the tumor-initiating capability of GBM tumorsphere cells. Therefore, we present a novel perspective on how hypoxia alters the pattern of one-carbon metabolism in GBM tumorsphere cells and provide evidence that restriction of methionine intake or targeting MAT2A inhibits the tumorigenicity of GBM tumorsphere cells.
Aging is a complex and heterogeneous process, raising important questions about how aging is differently impacted by underlying genetics and external factors. Recently, migrasomes, newly discovered organelles, have been identified to play important roles in various physiological and pathological processes by facilitating cell-to-cell communication. Thus far, their involvement in cellular senescence and aging remains largely unexplored. In this study, we aimed to investigate how migrasomes impact on cellular aging by leveraging multiple cellular senescence models, including replicatively senescent (RS), pathologically senescent and stress-induced senescent human mesenchymal stem cells (hMSCs), as well as RS human primary fibroblasts. In all cellular aging models, we detected an enhanced formation of migrasomes. Notably, migrasomes in senescent cells exhibited an accumulation of numerous aging hallmarks, such as dysfunctional mitochondria, endogenous retroviruses, and senescence-associated pro-inflammatory cytokines. Furthermore, we discovered that migrasomes derived from senescent cells can be taken up by young cells, thereby transferring aging signals and subsequently causing premature senescence phenotypes in recipient cells. Mechanistically, we found that treatment with migrasomes derived from senescent cells activated the innate immune response. Thus, our study sheds light on a pivotal role of migrasomes in mediating the contagiousness of aging.
Recurrent spontaneous abortion (RSA) affects 2%–5% of couples worldwide and remains a subject of debate regarding the effectiveness of lymphocyte immunotherapy (LIT) due to limited retrospective studies. We conducted a comprehensive Bayesian analysis to assess the impact of LIT on RSA. Using data from the Shenzhen Maternity and Child Healthcare Hospital (2001–2020, n = 2316), a Bayesian generalized linear model with predictive projection feature selection was employed. Our analysis revealed a significant improvement in live birth rates for RSA patients undergoing LIT. Notably, LIT had a greater impact compared to the other 85 factors considered. To mitigate research bias, we conducted a Bayesian meta-analysis combining our dataset with 19 previously reported studies (1985–2021, n = 4246). Additionally, we developed an empirical model high-lighting the four key factors, which are the LIT result, age, paternal blood type, and anticardiolipin antibody. Younger age (19–27), paternal blood type B, and a positive anticardiolipin antibody (IgM) were associated with better therapeutic outcomes in LIT for RSA. These findings aid clinicians in identifying suitable candidates for LIT and improving treatment outcomes.