TGF-β Signaling Research Articles

CeRNA profiling and the role in regulating gonadal development in gold pompano

BackgroundThe golden pompano (Trachinotus ovatus) is an economically significant warm-water aquaculture species in China. The time required for sexual maturity of T. ovatus is relatively long. Consequently, it has prompted researchers to investigate gonadal development process of this fish. To gain further insight into the function of competing endogenous RNA (ceRNA) in the gonads of T. ovatus and the regulatory mechanism of the ceRNA network, whole transcriptome libraries were constructed from the testes and ovaries.ResultsOverall, a total of 96 differentially expressed microRNAs (DE-miRNAs), 2,338 differentially expressed messenger RNAs (DE-mRNAs), 973 differentially expressed long non-coding RNAs (DE-lncRNAs), and 94 differentially expressed circular RNAs (DE-circRNAs) were identified. Additionally, a ceRNA network was constructed, and enrichment analysis confirmed the involvement of numerous pathways in reproduction and gonadal development, including the TGF-β signaling pathway and GnRH signaling pathway. The ceRNA network analysis revealed that the oni-let-7d-1-p3 and PC-3p-112794_13 may play significant roles in T. ovatus gonadal development. And we have observed a possible relationship related to gonadal development involving R-spondin-1 (Rspo1), oni-let-7d-1-p3, and MSTRG.14909.1 (lnc-TGFβR). Dual-luciferase gene reporter system and fluorescence in situ hybridization analyses preliminary verified the regulation relationship between Rspo1 and oni-let-7d-1-p3, as well as lnc-TGFβR and oni-let-7d-1-p3 in the cytoplasm of sertoli cells.ConclusionIt is hypothesized that the lnc-TGFβR functions as a sponge for oni-let-7d-1-p3, participating in regulating the process of testis development. These findings could enhance our understanding of ncRNAs in gonadal development. It also provides new insight into the function of ncRNAs and the regulatory relationship of ceRNA between males and females. These results might contribute to discussions on the regulation of ncRNA during gametogenesis.

Meta-analysis of retinal transcriptome profiling studies in animal models of myopia

ObjectiveMyopia prevalence is increasing at alarming rates, yet the underlying mechanistic causes are not understood. Several studies have employed experimental animal models of myopia and transcriptome profiling to identify genes and pathways contributing to myopia. In this study, we determined the retinal transcriptome changes in response to form deprivation in mouse retinas. We then conducted a transcriptome meta-analysis incorporating all publicly available datasets and analyzed how the results related to the genes associated with refractive errors in human genome-wide association studies (GWAS).MethodsForm deprivation was induced in three male C57BL6/J mice from postnatal day 28 (P28) to P42. Retinal gene expression was analyzed with RNA sequencing, followed by differential gene expression analysis with DESeq2 and identification of associated pathways with the Kyoto Encyclopedia of Genes and Genomes (KEGG). A systematic search identified four similar retinal transcriptomics datasets in response to experimental myopia using chicks or mice. The five studies underwent transcriptome meta-analyses to determine retinal gene expression changes and associated pathways. The results were compared with genes associated with human myopia.ResultsDifferential gene expression analysis of form-deprived mouse retinas revealed 235 significantly altered transcripts, implicating the BMP2 signaling pathway and circadian rhythms, among others. Transcriptome-wide meta-analyses of experimental myopia datasets found 427 differentially expressed genes in the mouse model and 1,110 in the chick model, with limited gene overlap between species. Pathway analysis of these two gene sets implicated TGF-beta signaling and circadian rhythm pathways in both mouse and chick retinas. Some pathways associated only with mouse retinal changes included dopamine signaling and HIF-1 signaling pathway, whereas glucagon signaling was only associated with gene changes in chick retinas. The follistatin gene changed in both mouse and chick retinas and has also been implicated in human myopia. TGF-beta signaling pathway and circadian entrainment processes were associated with myopia in mice, chicks, and humans.ConclusionThis study highlights the power of combining datasets to enhance statistical power and identify robust gene expression changes across different experimental animal models and conditions. The data supports other experimental evidence that TGF-beta signaling pathway and circadian rhythms are involved in myopic eye growth.

Unveiling novel biomarkers for platinum chemoresistance in ovarian cancer.

Primary chemoresistance to platinum-based treatment is observed in approximately 33% of individuals diagnosed with ovarian cancer; however, conventional clinical markers exhibit limited predictive value for chemoresistance. This study aimed to discover new genetic markers that can predict primary resistance to platinum-based chemotherapy. Through the analysis of three GEO datasets (GSE114206, GSE51373, and GSE63885) utilizing bioinformatics methodologies, we identified two specific genes, MFAP4 and EFEMP1. The findings revealed that the areas under the receiver operating characteristic curves for MFAP4 and EFEMP1 were 0.716 and 0.657 in the training cohort, and 0.629 and 0.746 in the testing cohort, respectively. In all cases or in cases treated with platin, high expression of MFAP4 and EFEMP1 was linked to shortened overall survival and progression-free survival. MFAP4 and EFEMP1 were positively correlated with epithelial-mesenchymal transition, TGF-β signaling, KRAS signaling, and so on. The high expression groups of MFAP4 and EFEMP1 exhibited elevated stromal, immune, and ESTIMATE scores. Finally, we constructed a regulatory network involving lncRNA-miRNA-mRNA interactions. In summary, MFAP4 and EFEMP1 have the potential to serve as predictive indicators for both response to platinum-based chemotherapy and survival rates, and might be regarded as innovative biomarkers and therapeutic targets for OC patients.

CSNK1E is involved in TGF-β1 induced epithelial mesenchymal transformationas and related to melanoma immune heterogeneity

IntroductionMelanoma (MM), the deadliest form of skin cancer, originates from melanocytes. Despite advances in immunotherapy that have somewhat improved the prognosis for MM patients, high levels of resistance to treatment continue to result in poor clinical outcomes. Identifying novel biomarkers and therapeutic targets is critical for improving the prognosis and treatment of MM.MethodsIn this study, we analyzed the expression patterns of WNT signaling pathway genes in MM and explored their potential mechanisms. Using Cox regression analysis, we identified 19 prognostic-related genes. Consistency clustering was performed to evaluate the potential of these genes as classifiers for prognosis. The Least Absolute Shrinkage and Selection Operator (LASSO) algorithm was then applied to refine the gene set and construct a 13-gene prognostic model. We validated the model at multiple time points to assess its predictive performance. Additionally, correlation analyses were performed to investigate the relationships between key genes and processes, including epithelial-to-mesenchymal transition (EMT) and immune responses.ResultsWe identified that CSNK1E and RAC3 were significantly positively correlated with the EMT process, with CSNK1E showing a similar expression trend to EMT-related genes. Both genes were also negatively correlated with multiple immune cell types and immune checkpoint genes. The 13-gene prognostic model demonstrated excellent predictive performance in MM prognosis. Pan-cancer analysis further revealed heterogeneous expression patterns and prognostic potential of CSNK1E across various cancers. Wet experiments confirmed that CSNK1E promotes MM cell proliferation, invasion, and migration, and enhances malignant progression through the TGF-β signaling pathway.DiscussionOur findings suggest that CSNK1E plays a crucial role in MM progression and could serve as a potential therapeutic target. The WNT and TGF-β pathways may work synergistically in regulating the EMT process in MM, highlighting their potential as novel therapeutic targets. These insights may contribute to the development of more effective treatments for MM, particularly for overcoming resistance to current therapies.

Critical role for Transglutaminase 2 in scleroderma skin fibrosis and in the development of dermal sclerosis in a mouse model of scleroderma.

Scleroderma is a life-threatening autoimmune disease characterized by inflammation, tissue remodelling, and fibrosis. This study aimed to investigate the expression and function of transglutaminase 2 (TGM2) in scleroderma skin and experimentally-induced dermal fibrosis to determine its potential role and therapeutic implications. We performed immunohistochemistry on skin sections to assess TGM2 expression and localisation, and protein biochemistry of both SSc-derived and healthy control dermal fibroblasts to assess TGM2 expression, function and ECM deposition in the presence of a TGM2 and TGFβ neutralizing antibodies and a small molecule inhibitor of the TGFβRI kinase. Mice with a complete deficiency of TGM2 (Tgm2-/-) were investigated in the bleomycin-induced model of skin fibrosis. TGM2 was found to be widely expressed in both control and scleroderma skin samples, as well as in cultured fibroblasts. Scleroderma fibroblasts exhibited elevated TGM2 expression, which correlated with increased expression of fibrosis markers (collagen type 1, αSMA and CCN2). Inhibition of TGM2 using a neutralizing antibody reduced the expression of key markers of fibrosis. The effects of TGM2 inhibition were similar to those observed with TGFβ neutralization, suggesting a potential cross-talk between TGM2 and TGFβ signalling. Moreover, TGM2 knock-out mice showed significantly reduced dermal fibrosis compared to wild-type mice. In vitro experiments with TGM2-deleted fibroblasts demonstrated impaired cell migration and collagen matrix contraction, which could be partially restored by exogenous TGFβ. TGM2 can regulate several key pro-fibrotic activities of TGFβ suggesting that attenuating TGM2 function may be of benefit in severe forms of connective tissue disease with skin fibrosis.

BMP4 regulates differentiation of nestin-positive stem cells into melanocytes

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.

Targeting circFOXO3 to Modulate Integrin β6 Expression in Periodontitis: A Potential Therapeutic Approach.

Circular RNA forkhead box O3 (circFOXO3) is crucial in regulating inflammation in lung and heart injuries. However, its role in periodontitis remains unclear. We sought to elucidate the effects of circFOXO3 on periodontitis progression and related molecular mechanisms. Reverse-transcription quantitative polymerase chain reaction and fluorescence insitu hybridization were used toquantify and localize circFOXO3 expression. The mechanism by which circFOXO3 promotes inflammation in periodontitiswas investigated using epithelial cells, human gingival epithelium and a rat model of ligature-induced periodontitis. circFOXO3 expression was abnormally high in the gingival epithelial tissues of patients with periodontitis. Elevated circFOXO3 levels down-regulated microRNA (miR)-141-3p, leading to increased FOXO3 expression. FOXO3 interacted with JunB to form a transcriptional-repression complex that inhibited the integrin β6 (ITGβ6)-mediated activation of transforming growth factor β (TGF-β) in epithelial cells. Through the miR-141-3p/FOXO3/JunB axis, circFOXO3 suppressed TGF-β signalling, thereby exacerbating periodontal inflammation. Finally, circFOXO3 inhibition hindered disease progression and restored TGF-β activity invivo via the FOXO3/JunB/ITGβ6 pathway. Our study identified a novel mechanism by which circFOXO3 contributes to periodontal inflammation through a complex transcriptional regulatory network involving miR-141-3p, FOXO3, JunB and ITGβ6. These findings highlight potential therapeutic targets for the development of effective treatments for this debilitating disease.

SREBF1 facilitates pathological retinal neovascularization by reprogramming the fatty acid metabolism of endothelial cells.

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disorder that critically affects the visual development of premature infants, potentially leading to irreversible vision loss or even blindness. Despite its significance, the underlying mechanisms of this disease remain insufficiently understood. In this study, we utilized the oxygen-induced retinopathy (OIR) mouse model and conducted endothelial functional assays to explore the role of Sterol Regulatory Element-Binding Protein 1 (SREBF1) in ROP pathogenesis. SREBF1 expression levels, along with its downstream targets, were investigated through Western blotting, RT-qPCR, and immunofluorescence staining techniques. Furthermore, Co-Immunoprecipitation (Co-IP) was employed to examine the molecular mechanisms involved. Our results demonstrated a significant increase in SREBF1 expression in both the OIR mouse model and hypoxic primary human retinal microvascular endothelial cells (HRMECs). Interventions conducted both in vivo and in vitro showed notable efficacy in reducing pathological neovascularization. Importantly, we discovered that SREBF1 plays a key role in modulating lipid metabolism in HRMECs by regulating the expression of ACC1 and FASN, leading to cellular reprogramming. This reprogramming influences HRMEC proliferation, migration, and tube formation through the HIF-1α/TGF-β signaling pathway, ultimately contributing to pathological retinal neovascularization. These findings provide new insights into the role of SREBF1 in angiogenesis within the context of ROP, offering potential therapeutic targets for the management and treatment of this disease.

Metabolomic and transcriptomic remodeling of bone marrow myeloid cells in response to maternal obesity.

Maternal obesity puts the offspring at high risk of developing obesity and cardio-metabolic diseases in adulthood. Here, we utilized a mouse model of maternal high-fat diet (HFD)-induced obesity that recapitulates metabolic perturbations seen in humans. We show increased adiposity in the offspring of HFD-fed mothers (Off-HFD) when compared to the offspring regular diet-fed mothers (Off-RD). We have previously reported significant immune perturbations in the bone marrow of newly-weaned Off-HFD. Here, we hypothesized that lipid metabolism is altered in the bone marrow of Off-HFD vs. Off-RD. To test this hypothesis, we investigated the lipidomic profile of bone marrow cells collected from three-week-old Off-RD and Off-HFD. Diacylgycerols (DAGs), triacylglycerols (TAGs), sphingolipids and phospholipids were remarkably different between the groups, independent of fetal sex. Levels of cholesteryl esters were significantly decreased in Off-HFD, suggesting reduced delivery of cholesterol. These were accompanied by age-dependent progression of mitochondrial dysfunction in bone marrow cells. We subsequently isolated CD11b+ myeloid cells from three-week-old mice and conducted metabolomics, lipidomics, and transcriptomics analyses. The lipidomic profiles of myeloid cells were similar to bone marrow cells and included increases in DAGs and decreased TAGs. Transcriptomics revealed altered expression of genes related to immune pathways including macrophage alternative activation, B-cell receptors, and TGFβ signaling. All told, this study revealed lipidomic, metabolomic, and gene expression abnormalities in bone marrow cells broadly, and in bone marrow myeloid cells particularly, in the newly-weaned offspring of mothers with obesity, which might at least partially explain the progression of metabolic and cardiovascular diseases in their adulthood.

Tgfβ signaling stimulates glycolysis to promote the genesis of synovial joint interzone in developing mouse embryonic limbs

Tgfβ signaling stimulates glycolysis to promote the genesis of synovial joint interzone in developing mouse embryonic limbs

LOX-induced tubulointerstitial fibrosis via the TGF-β/LOX/Snail axis in diabetic mice

BackgroundThe partial epithelial-mesenchymal transition (EMT) is emerging as a significant mechanism in diabetic nephropathy (DN). LOX is a copper amine oxidase conventionally thought to act by crosslinking collagen. However, the role of LOX in partial EMT and fibrotic progression in diabetic nephropathy has not been investigated experimentally.MethodsThe bulk RNA sequencing and single-nuclei RNA sequencing (snRNA-seq) analysis were explored to find the role of LOX in diabetic nephropathy. We then investigated the partial EMT and the possible signaling pathway of LOX, both in vivo and in vitro by LOX inhibition experiments in diabetic mice and HK-2 cells. Besides, we further assessed kidney fibrosis and renal function.ResultsLOX expression was elevated in kidneys of diabetic mice. Additionally, snRNA-seq results indicated that LOX expression was higher in partial epithelial-mesenchymal transition proximal tubular (PemtPT) epithelial cells. Moreover, we found that increased LOX prompted partial EMT of renal tubular epithelial cells (RTECs) by modulating the transcription factor Snail both in vivo and in vitro. Remarkably, inhibition of LOX effectively mitigated the partial EMT of RTECs in diabetic mice, thereby attenuating kidney fibrosis and enhancing renal function. Additionally, we identified the TGF-β signaling pathway as an upstream regulator of LOX, and inhibiting LOX partially reversed the partial EMT program in HK-2 cells induced by the TGF-β signaling pathway.ConclusionsHyperglycemia induces partial EMT of RTECs via the TGF-β/LOX/Snail axis, thereby contributing to diabetic kidney fibrosis. Inhibiting LOX can effectively reverse the partial EMT of RTECs, diminish diabetic kidney fibrosis, and improve renal function.

Direct reprogramming of human fibroblasts into hair-inducing dermal papilla cell-like cells by a single small molecule.

Dermal papilla cells (DPCs) are a crucial subset of mesenchymal cells in the skin responsible for regulating hair follicle development and growth, making them invaluable for cell-based therapies targeting hair loss. However, obtaining sufficient DPCs with potent hair-inducing abilities remains a persistent challenge. In this study, the Food and Drug Administration (FDA)-approved drug library was utilized to screen small molecules capable of reprogramming readily accessible human skin fibroblasts into functional DPCs. In the initial screening, five candidate small molecules were identified from a pool of 1,817 compounds, and the small molecule peficitinib was further identified by the further hair follicle regeneration experiments. Following peficitinib treatment, fibroblasts derived from primary human foreskin and scalp exhibited the capability to induce hair growth and possessed a molecular profile highly similar to that of primary DPCs. We refer to these cells as dermal papilla cell-like cells (DPC-LCs). Furthermore, transcriptome analysis showed that the wingless/integrated (Wnt) signaling pathway and the transforming growth factor β (TGF-β) signaling pathway, both of which play crucial roles in hair follicle morphogenesis, are upregulated and enriched in these DPC-LCs. These functional DPC-LCs offer a promising avenue for obtaining a plentiful supply of hair-inducing cells, thereby advancing the development of therapeutic strategies for hair loss treatment.

The master male sex determinant Gdf6Y of the turquoise killifish arose through allelic neofunctionalization

Although sex determination is a fundamental process in vertebrate development, it is very plastic. Diverse genes became major sex determinants in teleost fishes. Deciphering how individual sex-determining genes orchestrate sex determination can reveal new actors in sexual development. Here, we demonstrate that the Y-chromosomal copy of the TGF-β family member gdf6 (gdf6Y) in Nothobranchius furzeri, an emerging model organism in aging research, gained the function of the male sex determinant through allelic diversification while retaining the skeletal developmental function shared with the X-chromosomal gdf6 allele (gdf6X). Concerning sex determination, gdf6Y is expressed by somatic supporting cells of the developing testes. There it induces the male sex in a germ cell-independent manner in contrast to sex determination in zebrafish and the medaka. Looking for downstream effectors of Gdf6Y, we identified besides TGF-β signaling modulators, especially the inhibitor of DNA binding genes id1/2/3, the mRNA decay activator zfp36l2 as a new GDF6 signaling target.

A signaling molecule from intratumor bacteria promotes trastuzumab resistance in breast cancer cells

Emerging evidence indicates that intratumor bacteria exist as an active and specific tumor component in many tumor types beyond digestive and respiratory tumors. However, the biological impact and responsible molecules of such local bacteria-tumor direct interaction on cancer therapeutic response remain poorly understood. Trastuzumab is among the most commonly used drugs targeting the receptor tyrosine-protein kinase erbB-2 (ErbB2) in breast cancer, but its resistance is inevitable, severely limiting its clinical effectiveness. Here, we demonstrate that the quorum-sensing signaling molecule N-(3-oxo-dodecanoyl) homoserine lactone (3oc), a chemical compound released by Pseudomonas aeruginosa (P. aeruginosa), one tumor-resident bacteria with a relative high abundance in breast cancer, promotes breast cancer cell resistance to trastuzumab. Mechanically, 3oc directly leads to spontaneous dimerization of the transforming growth factor β (TGF-β) type II serine/threonine kinase receptor on the cell membrane in a ligand-independent manner. The 3oc-induced TGF-β signaling subsequently triggers ErbB2 phosphorylation and its downstream target activation, overcoming the inhibition effect of trastuzumab on ErbB2. With specific real-time qPCR, fluorescence in situ hybridization imaging, and liquid chromatography ionization tandem mass spectrometry analyses of clinical samples, we confirmed that P. aeruginosa and its signaling molecule 3oc exist in breast cancer tissues and there is a clinical correlation between P. aeruginosa colonization and trastuzumab resistance. This work expands the biological functions of intratumor bacteria in cancer treatment responsiveness and provides a unique perspective for overcoming trastuzumab resistance.

Identification of a novel disulfidptosis-related gene signature in osteoarthritis using bioinformatics analysis and experimental validation

Osteoarthritis (OA) is a degenerative bone disease characterized by the destruction of joint cartilage and synovial inflammation, involving intricate immune regulation processes. Disulfidptosis, a novel form of programmed cell death, has recently been identified; however, the effects and roles of disulfidptosis-related genes (DR-DEGs) in OA remain unclear. We obtained six OA datasets from the GEO database, using four as training sets and two as validation sets. Differential expression analysis was employed to identify DR-DEGs, and unique molecular subtypes of OA were constructed based on these DR-DEGs. Subsequently, the immune microenvironment of OA patients was comprehensively analyzed using the “CIBERSORT” algorithm for immune infiltration. Various machine learning algorithms were utilized to screen characteristic DR-DEGs, and nomogram models and ROC curves were built based on these genes. The scRNA dataset (GSE169454) was used to classify chondrocytes in OA samples into distinct cell types, further exploring the gene distribution and correlation of characteristic DR-DEGs with specific cell subpopulations. Moreover, the expression levels of four characteristic DR-DEGs were validated through OA cell models and rat models. In our study, we identified 10 DR-DEGs with significant differences in expression within OA samples. Based on these DR-DEGs, two distinct molecular subtypes were recognized (cluster 1 and 2). ZNF484 and NDUFS1 were found to be significantly overexpressed in subtype 1, while the infiltration abundance of activated mast cells was markedly elevated in subtype 2. Moreover, significant differences were observed in the infiltration proportions of 11 immune cell types between OA and control samples, with 9 DR-DEGs demonstrating substantial correlations with immune cell infiltration levels. Further analysis of the scRNA dataset revealed that SLC3A2 and NDUFC1 were predominantly expressed in the preHTC subpopulation. All 10 DR-DEGs exhibited notably higher expression in the EC subpopulation across various cell types. The proportion of EC subgroups with high SLC3A2 expression increased, mainly enriching pathways related to inflammation, such as the IL-17 signaling pathway and TGF-beta signaling pathway. Using machine learning, we identified four characteristic DR-DEGs, which, in combination with the nomogram and ROC models, demonstrated promising performance in the diagnosis of OA. Additionally, in vivo validation confirmed a significant elevation of PPM1F expression in OA models. This study identified DR-DEGs as potential biomarkers for the diagnosis and classification of OA and provided a preliminary understanding of their role in the immune microenvironment. However, further experimental and clinical studies are required to validate their diagnostic value and therapeutic potential.

JOSD2 promotes breast cancer metastasis by deubiquitinating and stabilizing SMAD4.

Breast cancer is one of the most common malignant tumors among women worldwide, and its high degree of metastasis significantly impacts treatment effectiveness leading to poor prognosis. The potential molecular mechanisms underlying breast cancer metastasis remain to be further elucidated. In this study, via database analysis, we revealed that the deubiquitinase josephin domain containing 2 (JOSD2) was abnormally amplified in patients with metastatic breast cancer, and was significantly negatively correlated with patient prognosis. By integrating data from the Gene Expression Omnibus (GEO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment analysis, we found that the transforming growth factor beta (TGF-β) signaling pathway was significantly activated in breast cancer patients with increased JOSD2 expression. Further studies revealed that JOSD2 interacted with and stabilized SMAD family member 4 (SMAD4) by removing polyubiquitin chains. Inhibition of JOSD2 by RNA interference effectively inhibited the metastasis of breast cancer cells both in vitro and in vivo. In conclusion, our study not only reveals the role of JOSD2 in promoting breast cancer metastasis for the first time, but also indicates promising directions for the future development of deubiquitinase inhibitors, which could yield significant therapeutic benefits. Nevertheless extensive research and development are required to fully realize this potential.

Molecular basis of interchain disulfide bond formation in BMP-9 and BMP-10.

BMP-9 and BMP-10 are TGF-β family signaling ligands naturally secreted into blood. They act on endothelial cells and are required for proper development and maintenance of the vasculature. In hereditary hemorrhagic telangiectasia, regulation is disrupted due to mutations in the BMP-9/10 pathway, namely in the type I receptor ALK1 or the co-receptor endoglin. It has been demonstrated that BMP-9/10 heterodimers are the most abundant signaling species in the blood, but it is unclear how they form. Unlike other ligands of the TGF-β family, BMP-9 and -10 are secreted as a mixture of disulfide-linked dimers and monomers in which the interchain cysteine (Cys-392) remains either unpaired or paired. Here, we show that the monomers are secreted in a cysteinylated form that crystallizes as a non-covalent dimer. Despite this, monomers do not self-associate at micromolar or lower concentrations and have reduced signaling potency compared to disulfide-linked dimers. We further show using protein crystallography that the interchain disulfide of the BMP-9 homodimer adopts a highly strained syn-periplanar conformation. Hence, geometric strain across the interchain disulfide is responsible for infrequent interchain disulfide bond formation, not the cysteinylation. Additionally, we show that interchain disulfide bond formation occurs less in BMP-9 than BMP-10 and these frequencies can be reversed by swapping residues near the interchain disulfide that form attractive interactions with the opposing protomer. Finally, we discuss the implications of these observations on BMP-9/10 heterodimer formation.

5-methoxytryptophan protects against toll-like receptor 2 mediated renal tissue inflammation and fibrosis in a murine unilateral ureteral obstruction model.

5-methoxytryptophan (5-MTP) is an anti-inflammatory metabolite. Several recent reports indicate that 5-MTP protects against post-injury tissue fibrosis. It was unclear how 5-MTP controls tissue fibrosis. We postulated that 5-MTP attenuates renal interstitial fibrosis by blocking toll-like receptor 2 (TLR2) and transforming growth factor β (TGFβ) signaling pathways. The effect of 5-MTP on renal fibrosis was evaluated by pretreatment of wild-type UUO mice with intraperitoneal administration of 5-MTP. To determine whether 5-MTP attenuates fibrosis by inhibiting TLR2 and TGFβ signaling pathways, we evaluated the effect of 5-MTP on TLR2-induced fibroblast phenotypic switch in NRK-49F fibroblasts and TLR2 and TGFβ signaling pathways in human proximal tubular epithelial cells (HPTEC) and RAW264.7 macrophages stimulated with Pam3CSK4 (Pam3) or TGFβ1. UUO-induced renal fibrosis was abrogated in tlr2-/- mice consistent with a crucial role of TLR2 in UUO-induced renal fibrosis. UUO-induced macrophage infiltration and pro-fibrotic cytokine production in renal tissues were suppressed by tlr2 knockout. 5-MTP attenuated renal tissue fibrosis accompanied by reduction of macrophage infiltration and IL-6 and TGFβ levels. 5-MTP inhibits TLR2 upregulation and blocks TLR2-MyD88-TRAF6 signaling pathway in macrophages. Furthermore, 5-MTP blocked Pam3- and TGFβ1-induced phenotypic switch of NRK-49F to myofibroblasts and inhibited Pam3- and TGFβ1-induced signaling pathways in HPTECs and RAW264.7 cells. 5-MTP effectively protects against UUO-induced renal interstitial fibrosis by blocking TLR2 and TGFβ signaling pathways.

The potential role of SCF combined with DPCs in facial nerve repair.

Facial nerve injuries lead to significant functional impairments and psychological distress for affected patients. Effective repair of these injuries remains a challenge. For longer nerve gaps, the regeneration outcomes after nerve grafting remain suboptimal due to limited sources and postoperative immune responses. Tissue engineering techniques are conventional methods for repairing peripheral nerve defects. This study explores the potential of dental pulp cells (DPCs) combined with stem cell factor (SCF) to enhance neurogenic differentiation and improve facial nerve regeneration. DPCs were isolated from rabbit dental pulp, the pluripotency of the cells was identified from three perspectives: osteogenic differentiation, adipogenic differentiation, and neurogenic differentiation. In vivo experiments involved injuring the buccal branch of the facial nerve in New Zealand white rabbits, followed by treatment with PBS, DPCs, SCF, or SCF + DPCs. Functional recovery was assessed over 12weeks, with SCF + DPCs demonstrating the most significant improvement in whisker movement scores. Histomorphological evaluations revealed enhanced myelinated fiber density and axonal morphology in the SCF + DPCs group. RNA sequencing identified 608 differentially expressed genes, with enrichment in the TGF-β signaling pathway. In in vitro experiments, we demonstrated from multiple angles using Western blot analysis, Real-time quantitative polymerase chain reaction (QPCR) analysis, and immunofluorescence staining that SCF can promote the neurogenic differentiation of DPCs through the TGF-β1 signaling pathway. Our findings indicate that the combination of SCF and DPCs offers a promising strategy for enhancing facial nerve repair.

DYRK1A-TGF-β signaling axis determines sensitivity to OXPHOS inhibition in hepatocellular carcinoma.

Intervening in mitochondrial oxidative phosphorylation (OXPHOS) has emerged as a potential therapeutic strategy for certain types of cancers. Employing kinome-based CRISPR screen, we find that knockout of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) synergizes with OXPHOS inhibitor IACS-010759 in liver cancer cells. Targeting DYRK1A combined with OXPHOS inhibitors activates TGF-β signaling, which is crucial for OXPHOS-inhibition-triggered cell death. Mechanistically, upregulation of glutamine transporter solute carrier family 1 member 5 (SLC1A5) transcription compensates for the increased glutamine requirement upon OXPHOS inhibition. DYRK1A directly phosphorylates SMAD3 Thr132, thereby suppressing the negative impact of TGF-β signaling on transcription of SLC1A5, leading to intrinsic resistance of liver cancer cells to OXPHOS inhibition. Moreover, we demonstrate the therapeutic efficacy of IACS-010759 in combination with DYRK1A inhibition in multiple liver cancer models, including xenografts, patient-derived xenografts, and spontaneous tumor model. Our study elucidates how the DYRK1A-TGF-β signaling axis controls the response of tumor cells to OXPHOS inhibition and provides valuable insights into targeting OXPHOS for liver cancer therapy.