Cellular and Molecular Life Sciences最新文献

Hair follicle (HF) development and pigmentation are complex processes governed by various signaling pathways, such as TGF-β and FGF signaling pathways. Nestin + (neural crest like) stem cells are also expressed in HF stem cells, particularly in the bulge and dermal papilla region. However, the specific role and differentiation potential of these Nestin-positive cells within the HF remain unclear, especially regarding their contribution to melanocyte formation and hair pigmentation. Bone morphogenetic protein 4 (BMP4), members of the TGFβ family, has been implicated in regulating HF growth, coloration, and related cellular behaviors. Its role in directing Nestin-positive cells toward a melanocytic lineage has yet to be fully explored. In this study, mouse HF organoids were constructed and shown to be an ideal model for studying HF growth and development in vitro. Using this model as a basis, we demonstrated that BMP4 controls HF coloration as well as its length, number, and even size. Furthermore, Nestin-positive cells in the HF-especially those in the bulge region-differentiate into melanocytes, which produce the pigments that give HF its color under BMP4 stimulation. The resulting increase in pigmentation within the mouse HF organoids underscores that BMP4 has a major regulatory role in the formation of melanocytes from Nestin-positive stem cells. This research provides insights into the cellular mechanisms underlying hair pigmentation and suggests potential therapeutic applications for pigmentation disorders.

Background: Diabetes is a primary contributor to diabetic cardiomyopathy (DbCM), which is marked by metabolic imbalances such as elevated blood glucose and lipid levels, leading to significant structural and functional alterations in the myocardium. Elevated free fatty acids (FFAs) and hyperglycemia play critical roles in DbCM development, with FFAs inducing insulin resistance in cardiomyocytes and promoting lipid accumulation, resulting in oxidative stress and fibrosis. Current research suggests that glucagon-like peptide-1 (GLP-1) receptor agonists may effectively mitigate DbCM, although an effective treatment for this condition remains elusive, and the precise mechanisms of this protective effect are not fully understood.

Methods: In this study, we aimed to replicate diabetic glucolipotoxic conditions by treating differentiated H9c2 cells with high glucose and free fatty acids. Additionally, a diabetic cardiomyopathy model was induced in mice through high-fat diets. Both in vitro and in vivo models were used to investigate the protective effects of liraglutide on cardiomyocytes and elucidate its underlying molecular mechanisms.

Results: Our findings indicate that liraglutide significantly reduces lipid droplet (LD) formation and myocardial fibrosis, as evidenced by decreased expression of fibrosis markers, including TGF-β1 and collagen types I and III. Liraglutide also enhanced AMP-activated protein kinase (AMPK) activation, which improved mitochondrial function, increased antioxidant gene expression, enhanced insulin signaling, and reduced oxidative stress.

Conclusions: These results demonstrate the potential therapeutic role of liraglutide in managing diabetes-related cardiac complications, offering a comprehensive approach to improving cardiac outcomes in patients with diabetes.

Glycans are known to be fundamental for many cellular and physiological functions. Congenital disorders of glycosylation (CDG) currently encompassing over 160 subtypes, are characterized by glycan synthesis and/or processing defects. Despite the increasing number of CDG patients, therapeutic options remain very limited as our knowledge on glycan synthesis is fragmented. The emergence of CDG resulting from defects in ER/ Golgi homeostasis makes this even more difficult. SLC10A7 belongs to the SLC10 protein family, known as bile acid and steroid transport family, exhibiting a unique structure. It shows a ubiquitous expression and is linked to negative calcium regulation in cells. The mechanisms by which SLC10A7 deficiency leads to Golgi glycosylation abnormalities are unknown. The present study identifies major O-glycosylation defects in both SLC10A7 KO HAP1 cells and SLC10A7-CDG patient fibroblasts and reveals an increased ER and Golgi calcium contents. We also show that the abundance of COSMC and C1GALT1 is altered in SLC10A7-CDG patient cells, as well as the subcellular Golgi localization of the Ca²⁺-binding Cab45 protein. Finally, we demonstrate that supraphysiological manganese supplementation suppresses the deficient electrophoretic mobility of TGN46 by an aberrant transfer of GalNAc residues, and reveal COSMC Mn²⁺ sensitivity. These findings provide novel insights into the mechanisms of Golgi glycosylation defects in SLC10A7-deficient cells. They show that SLC10A7 is a key Golgi transmembrane protein maintaining the tight regulation of Ca²⁺ homeostasis in the ER and Golgi compartments, both essential for glycosylation.

The mechanism by which DNA-damage affects self-renewal and pluripotency remains unclear. DNA damage and repair mechanisms have been largely elucidated in mutated cancer cells or simple eukaryotes, making valid interpretations on early development difficult. Here we show the impact of ionizing irradiation on the maintenance and early differentiation of mouse embryonic stem cells (ESCs). Our findings demonstrate that irradiation induces the upregulation of the p53 family genes, including p53, p63, and p73, resulting in elevated expression of the E3 ubiquitin ligases Itch and Trim32. Consequently, this impairs ESC maintenance by reducing the protein levels of key pluripotency transcription factors in both mouse ESCs and early embryos. Notably, our study reveals that irradiation-induced DNA damage leads to the recruitment of the BAF complex, causing it to dissociate from its binding sites on the target genes associated with the Yap, Wnt, and TGF-β pathways, thereby increasing signaling and promoting differentiation of ESCs into all three lineages. Importantly, pathway inhibition demonstrates that DNA damage accelerated ESC differentiation relies on Wnt and TGF-β, and is selectively dependent on p53 or p63/ p73 for mesoderm and endoderm respectively. Finally, our study reveals that p53 family proteins form complexes with effector proteins of key signaling pathways which actively contribute to ESC differentiation. In summary, this study uncovered a mechanism by which multiple differentiation signaling pathways converge on the p53 family genes to promote ESC differentiation and are impacted by exposure to ionizing radiation.

An aberrant pro-inflammatory microglia response has been associated with most neurodegenerative disorders. Identifying microglia druggable checkpoints to restore their physiological functions is an emerging challenge. Recent data have shown that microglia produce de novo neurosteroids, endogenous molecules exerting potent anti-inflammatory activity. Here, the role of neurosteroidogenesis in the modulation of microgliosis was explored in human microglia cells. In particular, CYP11A1 inhibition or TSPO pharmacological stimulation, crucial proteins involved in the rate limiting step of the neurosteroidogenic cascade, were employed. CYP11A1 inhibition led microglia to acquire a dysfunctional and hyperreactive phenotype, while selective TSPO ligands promoted the establishment of an anti-inflammatory one. Analysis of specific neurosteroid levels (neurosteroidome) identified allopregnanolone/pregnanolone as crucial metabolites allowing controlled activation of microglia. Importantly, the neurosteroid shift towards a greater androgenic/estrogenic profile supported the transition from pro-inflammatory to neuroprotective microglia, suggesting the therapeutic potential of de novo microglial neurosteroidogenesis stimulation for neuroinflammatory-related disorders.

Herpes simplex virus type I (HSV-1) infection is associated with lung injury; however, no specific treatment is currently available. In this study, we found a significant negative correlation between FcRn levels and the severity of HSV-1-induced lung injury. HSV-1 infection increases the methylation of the FcRn promoter, which suppresses FcRn expression by upregulating DNMT3b expression. Analysis of the FcRn promoter revealed that the -1296- to -919-bp region is the key regulatory region, with the CG site at -967/-966 bp being the critical methylation site. The transcription factor JUN binds to this CG site to increase FcRn transcription; however, its activity was significantly inhibited by DNMT3b overexpression. Moreover, 5-Aza-2 effectively reduced HSV-1-induced lung injury and inhibited ferroptosis. Transcriptomic sequencing revealed that the ferroptosis pathway was highly activated in the lung tissues of FcRn-knockout mice via the p53/SLC7A11 pathway. Furthermore, in vivo and in vivo experiments showed that FcRn knockout aggravated lung epithelial cell inflammation by promoting ferroptosis; however, this effect was reversed by a ferroptosis inhibitor. Thus, HSV-1 infection suppressed FcRn expression through promoter methylation and promoted ferroptosis and lung injury. These findings reveal a novel molecular mechanism underlying viral lung injury and suggest potential therapeutic strategies for targeting FcRn.

Background: Perioperative neurocognitive disorder (PND) is a prevalent form of cognitive impairment in elderly patients following anesthesia and surgery. The underlying mechanisms of PND are closely related to perineuronal nets (PNNs). PNNs, which are complexes of extracellular matrix primarily surrounding neurons in the hippocampus, play a critical role in neurocognitive function. Connexin 43 (Cx43) contributes to cognitive function by modulating the components of PNNs. This study was designed to investigate the specific regulatory mechanisms of Cx43 on PNNs and its pivotal role in the development of PND.

Methods: Eighteen-month-old wild-type and Gja1^fl/fl C57BL/6 mice were subjected to abdominal surgery under 1.4% isoflurane anesthesia. Cognitive functions, particularly learning and memory, were evaluated via the Y-maze test, Barnes maze (BM) and contextual fear conditioning test (CFT). The mRNA and protein expression levels of Cx43 were assessed by using quantitative reverse transcription polymerase chain reaction (qRT-PCR), fluorescent in situ hybridization (FISH), western blotting and flow cytometry. The quantity of PNNs was measured by Wisteria floribunda agglutinin (WFA) and Aggrecan staining.

Results: Aged mice subjected to anesthesia and surgery exhibited deficits in hippocampus-dependent cognitive functions, which were accompanied by increased Cx43 mRNA and protein expression. Conditional knockout (cKO) of Cx43 in astrocytes alleviated cognitive deficits and promoted the number of PNNs and dendritic spines in the hippocampus by targeting Dmp1. Knockdown of Dmp1 attenuated the beneficial effects of Cx43 cKO on cognitive deficits induced by anesthesia and surgery.

Conclusion: Our findings indicate that anesthesia and surgery induce an increase in Cx43 expression, which inhibits the formation of PNNs and dendritic spines in hippocampus by suppressing Dmp1 transcription, leading to cognitive deficits in aged mice. These results offer new mechanistic insights into the pathogenesis of PND and identify potential targets for therapeutic intervention.

Osteoporosis is characterized by decreased bone mass and accumulation of adipocytes in the bone marrow. The mechanism underlying the imbalance between osteoblastogenesis and adipogenesis in bone marrow mesenchymal stem cells (BMSCs) remains unclear. We found that ALG5 was significantly downregulated in BMSCs from osteoporotic specimens. ALG5 knockdown inhibited osteogenic differentiation and increased adipogenic differentiation of BMSCs. ALG5 deficiency diminished the N-glycosylation of SLC6A9, thereby altering its protein stability and disrupting SLC6A9-mediated glycine uptake in BMSCs. ALG5 overexpression by adeno-associated virus serotype 9 (rAAV9) alleviated bone loss in OVX mice. Taken together, our findings suggest a novel role for the ALG5-SLC6A9-glycine axis in the imbalance of BMSC differentiation in osteoporosis. Moreover, we identify ALG5 overexpression as a potential therapeutic strategy for treating osteoporosis.

Organoid is an ideal in vitro model with cellular heterogeneity and genetic stability when passaging. Currently, organoids are exploited as new tools in a variety of preclinical researches and applications for disease modeling, drug screening, host-microbial interactions, and regenerative therapy. Advances have been made in the establishment of nasal and olfactory epithelium organoids that are used to investigate the pathogenesis of smell-related diseases and cellular/molecular mechanism underlying the regeneration of olfactory epithelium. A set of critical genes are identified to function in cell proliferation and neuronal differentiation in olfactory epithelium organoids. Besides, nasal epithelium organoids derived from chronic rhinosinusitis patients have been established to reveal the pathogenesis of this disease, potentially applied in drug responses in individual patient. The present article reviews recent research progresses of nasal and olfactory epithelium organoids in fundamental and preclinical researches, and proposes current advances and potential future direction in the field of organoid research and application.

Over the past few decades, microtubules have been targeted by various anticancer drugs, including paclitaxel and eribulin. Despite their promising effects, the development of drug resistance remains a challenge. We aimed to define a novel cell death mechanism that targets microtubules using eribulin and to assess its potential in overcoming eribulin resistance. Notably, treating non-resistant breast cancer cells with eribulin led to increased microtubule acetylation around the nucleus and cell death. Conversely, eribulin-resistant (EriR) cells did not exhibit a similar increase in acetylation, even at half-maximal inhibitory concentrations. Interestingly, silencing the ATAT1 gene, which encodes the α-tubulin N-acetyltransferase 1 (the enzyme responsible for microtubule acetylation), induces eribulin resistance, mirroring the phenotype of EriR cells. Moreover, eribulin-induced acetylation of microtubules facilitates the transport of Ca²⁺ from the ER to the mitochondria, releasing cytochrome c and subsequent cell death. Transcriptome analysis of EriR cells revealed a significant downregulation of ER stress-induced apoptotic signals, particularly the activity of protein kinase RNA-like ER kinase (PERK), within the unfolded protein response signaling system. Pharmacological induction of microtubule acetylation through a histone deacetylase 6 inhibitor combined with the activation of PERK signaling using the PERK activator CCT020312 in EriR cells enhanced mitochondrial Ca²⁺ accumulation and subsequent cell death. These findings reveal a novel mechanism by which eribulin-induced microtubule acetylation and increased PERK activity lead to Ca²⁺ overload from the ER to the mitochondria, ultimately triggering cell death. This study offers new insights into strategies for overcoming resistance to microtubule-targeting agents.