Non-Smad TGF-β signals

Long non-coding RNAs are involved in the crosstalk between cancer-associated fibroblasts and tumor cells

The proliferation of tumors is not merely self-regulated by the cancer cells but is also intrinsically connected to the tumor microenvironment (TME). Within this complex TME, cancer-associated fibroblasts (CAFs) are pivotal in the modulation of tumor onset and progression. Rich signaling interactions exist between CAFs and tumor cells, which are crucial for tumor regulation. Long non-coding RNAs (LncRNAs) emerge from cellular transcription as a class of functionally diverse RNA molecules. Recent studies have revealed that LncRNAs are integral to the crosstalk between CAFs and tumor cells, with the capacity to modify cellular transcriptional activity and secretion profiles, thus facilitating CAFs activation, tumor proliferation, metastasis, drug resistance, and other related functionalities. This comprehensive review revisits the latest research on LncRNA-mediated interactions between CAFs and tumor cells, encapsulates the biological roles of LncRNAs, and delves into the molecular pathways from a broader perspective, aspiring to offer novel perspectives for a deeper comprehension of the etiology of tumors and the enhancement of therapeutic approaches.

Cytokine modulation in pelvic organ prolapse and urinary incontinence: from molecular insights to therapeutic targets

Pelvic organ prolapse (POP) and urinary incontinence (UI) are common disorders that significantly impact women's quality of life. Studies have demonstrated that cytokines, including pro- and anti-inflammatory immune mediators, play a role in illness genesis and progression. Research on the inflammatory milieu of the pelvic floor has shown that POP patients have increased inflammation in vaginal tissues. This evidence revealed that significant changes in the inflammatory milieu of the pelvic floor are an aspect of the pathogenesis of POP. POP patients exhibit increased levels of inflammatory cytokines (IL-1, TNF, IFN, and others) in the front vaginal wall, which may alter collagen metabolism and contribute to POP. Studies indicate that cytokines such as IL-6, IL-10, and TGF, which are involved in inflammation, remodelling, and repair, have dual effects on POP and UI. They can promote tissue healing and regeneration but also exacerbate inflammation and fibrosis, contributing to the progression of these conditions. Understanding the dual roles of these cytokines could help us improve the vaginal microenvironment of women and treat POP and UI. Given the considerable changes in these cytokines, this review addresses studies published between 2000 and 2024 on the molecular mechanisms by which pro- and anti-inflammatory cytokines affect women with POP and UI. Furthermore, we explain novel therapeutic strategies for cytokine regulation, emphasizing the possibility of personalized treatments that address the underlying inflammatory milieu of the vagina in POP and UI patients. This thorough analysis aims to establish a foundation for future research and clinical applications, ultimately improving patient outcomes via designed cytokine-based therapies.

Computational Modeling and Analysis of the TGF-β-induced ERK and SMAD Pathways

TGF-β, an important cytokine that plays a key role in many diseases regulates a wide array of cellular and physiologic processes via several TGF-β-driven signaling cascades, including the SMAD and non-SMAD-driven pathways. However, the detailed mechanisms by which TGF-β induces such diverse responses remain poorly understood. In particular, compared to the SMAD-dependent pathway, SMAD-independent pathways such as the ERK/MAPK pathway, which is critical in cancer progression, are less characterized. Here, we develop an integrated mechanistic model of the TGF-β-triggered ERK activation pathway and its crosstalk with the SMAD pathway, an analysis of which demonstrates how SMAD dynamics can be significantly modulated and regulated by the ERK pathway. In particular, SMAD-mediated transcription can be altered and delayed due to expedited phosphorylation of the linker of SMAD by TGF-β-activated ERK; and enhanced ERK activity, but attenuated SMAD activity, can be achieved simultaneously by fast turnover of TGF-β receptors via lipid-rafts. Also, in silico mutations of the TGF-β pathways reveal that the dynamic characteristics of both SMAD and ERK signaling may change significantly during cancer development. Specifically, normal cells may exhibit enhanced and sustained SMAD signaling with transient ERK activation, whereas cancerous cells may produce elevated and prolonged ERK signaling with enervated SMAD activation. These distinctive differences between normal and cancerous signaling behavior provide clues concerning, and potential explanations for, the seemingly contradictory roles played by TGF-β during cancer progression. We demonstrate how crosstalk among various branch pathways of TGF-β can influence overall cellular behavior. Based on model analysis, we hypothesize that aberrant molecular alterations drive changes in the intensity and duration of SMAD and ERK signaling during cancer progression and ultimately lead to an imbalance between the SMAD and ERK pathways in favor of tumor promotion. Thus, to treat cancer patients with a genetic signature of oncogenic Ras effectively may require at least a combination therapy to restore both the expression of TGF-β receptors and the GTPase activity of Ras.

TGF-β-Induced PAUF Plays a Pivotal Role in the Migration and Invasion of Human Pancreatic Ductal Adenocarcinoma Cell Line Panc-1

Pancreatic adenocarcinoma upregulated factor (PAUF) was initially identified as a secreted protein that is substantially expressed in pancreatic ductal adenocarcinoma (PDAC). PAUF also affects invasiveness, motility, and the proliferation of cells in several types of cancer. Recently, PAUF was reported to play a pivotal role in the TLR4-mediated migration and invasion of PDAC cells. However, the mechanism inducing PAUF expression and its functional role in TGF-β-stimulated PDAC cells have not yet been studied. Thus, we first assessed whether TGF-β regulates PAUF expression in several PDAC cell lines and found a significant increase in PAUF expression in Smad signaling-positive Panc-1 cells treated with TGF-β. We also found that the PAUF promoter region contains a Smad-binding element. TGF-β-treated Panc-1 cells showed an increase in PAUF promoter activity, but this effect was not observed in TGF-β-stimulated Smad4-null BxPC-3 cells. Restoring Smad4 expression increased the PAUF promoter activity and expression in Smad4-overexpressing BxPC-3 cells treated with TGF-β. We further found that PAUF aggravated the TGF-β-induced epithelial-mesenchymal transition (EMT) in Panc-1 and BxPC-3 cells via the activation of MEK-ERK signaling. These results indicate that TGF-β/Smad signaling-mediated upregulation of PAUF plays a crucial role in EMT progression by activating the TGF-β-mediated MEK-ERK signaling pathway.

SMAD4 mutations causing Myhre syndrome are under positive selection in the male germline

While it is widely thought that de novo mutations (DNMs) occur randomly, we previously showed that some DNMs are enriched because they are positively selected in the testes of aging men. These "selfish" mutations cause disorders with a shared presentation of features, including exclusive paternal origin, significant increase of the father's age, and high apparent germline mutation rate. To date, all known selfish mutations cluster within the components of the RTK-RAS-MAPK signaling pathway, a critical modulator of testicular homeostasis. Here, we demonstrate the selfish nature of the SMAD4 DNMs causing Myhre syndrome (MYHRS). By analyzing 16 informative trios, we show that MYHRS-causing DNMs originated on the paternally derived allele in all cases. We document a statistically significant epidemiological paternal age effect of 6.3 years excess for fathers of MYHRS probands. We developed an ultra-sensitive assay to quantify spontaneous MYHRS-causing SMAD4 variants in sperm and show that pathogenic variants at codon 500 are found at elevated level in sperm of most men and exhibit a strong positive correlation with donor's age, indicative of a high apparent germline mutation rate. Finally, we performed in vitro assays to validate the peculiar functional behavior of the clonally selected DNMs and explored the basis of the pathophysiology of the different SMAD4 sperm-enriched variants. Taken together, these data provide compelling evidence that SMAD4, a gene operating outside the canonical RAS-MAPK signaling pathway, is associated with selfish spermatogonial selection and raises the possibility that other genes/pathways are under positive selection in the aging human testis.

Analysis of the Dynamic Expression of the SMAD Family in the Periosteum During Guided Bone Regeneration

OBJECTIVE

The aim of this study was to investigate the dynamic expression of the SMAD family during guided bone regeneration for the reconstruction of cranio-maxillofacial bone defects.

METHODS

A swine model of guided bone regeneration was established with one side of the rib as the trauma group and the contralateral as control group. Periosteal and regenerative tissue specimens were harvested at 9 time points in the early, middle, and late phases, and were subjected to gene sequencing and tissue staining. Expression data of each SMAD family were extracted for further analysis, in which the correlation of the expression of the respective members within and between groups and at different time points was analyzed.

RESULTS

The expression of individual members of the SMAD family fluctuates greatly, especially during the first month. The SMAD3 and SMAD4 genes were the most highly expressed. The foldchange value of SMAD6 was the largest and remained above 1.5 throughout the process. The dynamic expression levels of SMAD2, SMAD4, SMAD5, SMAD6, and SMAD9 showed a significant positive correlation in both groups. The expression levels of each gene showed a positive correlation with other SMAD genes. Tissue staining showed that the overall contour of the regenerated bone tissue was basically formed within the first 1 month.

CONCLUSION

The first month of guided bone regeneration is a critical period for bone regeneration and is an important period for the SMAD family to play a role. The SMAD6 may play an important role in the whole process of guided bone regeneration.

Immunomodulatory signalling networks in glioblastoma multiforme: a comprehensive review of therapeutic approaches

Glioblastoma multiforme is a very aggressive type of cancer with high mortality and poor prognosis worldwide. Advanced treatment options with an understanding of the molecules and signalling mechanisms involved in this type of cancer have the potential to increase targeted therapy and decrease off-target effects, resistance, and recurrence. Glioblastoma multiforme (GBM) presents a complex tumour microenvironment with numerous cellular components and an extracellular matrix comprising multiple components. A deeper understanding of these components and corresponding signalling pathways can increase the success of immune checkpoint inhibitors in the treatment of GBM. The discovery of specific molecular changes and biomarkers has led to the investigation of tailored treatments for individual patients. Combination therapies targeting multiple pathways or utilizing different modalities are emerging as a promising strategy albeit with challenges in drug delivery to the brain. The review presents a comprehensive update of the various immunomodulatory signalling networks in GBM and highlights the corresponding therapeutic approaches by targeting them.

ΔNp63 bookmarks and creates an accessible epigenetic environment for TGFβ-induced cancer cell stemness and invasiveness

BACKGROUND

p63 is a transcription factor with intrinsic pioneer factor activity and pleiotropic functions. Transforming growth factor β (TGFβ) signaling via activation and cooperative action of canonical, SMAD, and non-canonical, MAP-kinase (MAPK) pathways, elicits both anti- and pro-tumorigenic properties, including cell stemness and invasiveness. TGFβ activates the ΔNp63 transcriptional program in cancer cells; however, the link between TGFβ and p63 in unmasking the epigenetic landscape during tumor progression allowing chromatin accessibility and gene transcription, is not yet reported.

METHODS

Small molecule inhibitors, including protein kinase inhibitors and RNA-silencing, provided loss of function analyses. Sphere formation assays in cancer cells, chromatin immunoprecipitation and mRNA expression assays were utilized in order to gain mechanistic evidence. Mass spectrometry analysis coupled to co-immunoprecipitation assays revealed novel p63 interactors and their involvement in p63-dependent transcription.

RESULTS

The sphere-forming capacity of breast cancer cells was enhanced upon TGFβ stimulation and significantly decreased upon ΔNp63 depletion. Activation of TGFβ signaling via p38 MAPK signaling induced ΔNp63 phosphorylation at Ser 66/68 resulting in stabilized ΔNp63 protein with enhanced DNA binding properties. TGFβ stimulation altered the ratio of H3K27ac and H3K27me3 histone modification marks, pointing towards higher H3K27ac and increased p300 acetyltransferase recruitment to chromatin. By silencing the expression of ΔNp63, the TGFβ effect on chromatin remodeling was abrogated. Inhibition of H3K27me3, revealed the important role of TGFβ as the upstream signal for guiding ΔNp63 to the TGFβ/SMAD gene loci, as well as the indispensable role of ΔNp63 in recruiting histone modifying enzymes, such as p300, to these genomic regions, regulating chromatin accessibility and gene transcription. Mechanistically, TGFβ through SMAD activation induced dissociation of ΔNp63 from NURD or NCOR/SMRT histone deacetylation complexes, while promoted the assembly of ΔNp63-p300 complexes, affecting the levels of histone acetylation and the outcome of ΔNp63-dependent transcription.

CONCLUSIONS

ΔNp63, phosphorylated and recruited by TGFβ to the TGFβ/SMAD/ΔNp63 gene loci, promotes chromatin accessibility and transcription of target genes related to stemness and cell invasion.

Functional evidence for two distinct mechanisms of action of progesterone and selective progesterone receptor modulator on uterine leiomyomas

OBJECTIVE

To study the specific mechanisms through which progesterone and selective progesterone receptor modulators impact the growth, synthesis, and accumulation of the extracellular matrix in uterine leiomyomas.

DESIGN

Laboratory study.

SETTING

Academic Research Institutions.

PATIENTS (S)

This study involved reproductive-age women diagnosed with infertility associated uterine leiomyomas who underwent myomectomy either after selective progesterone receptor modulator ulipristal acetate (UA) treatment or without any pharmacological pretreatment. Control samples included healthy myometrium tissue (n = 100). Specimens were obtained from the Department of Reproduction and Gynecological Endocrinology and Biobank, Medical University of Bialystok, Poland.

INTERVENTIONS

Daily (5 mg/d) UA treated for 2 months (n = 100) and untreated (n = 150) patients with uterine leiomyomas or normal healthy myometrium (n = 100) tissue samples immediately after surgery were collected for transcriptional analysis and assessments.

MAIN OUTCOME MEASURES

Progesterone-induced activation of the signaling pathways related to uterine leiomyomas extracellular matrix synthesis, deposition, and growth, as well as the expression profile of progesterone receptors in uterine leiomyomas, were assessed.

RESULTS

The results indicated that progesterone activated the transforming growth factor-β and SMAD3 signaling pathways and promoted proliferation, growth, and extracellular matrix remodeling in uterine leiomyomas by up-regulating SMAD3, transforming growth factor-β (TGF-β) receptor type 1 and II, Ras homolog A, vascular endothelial growth factor, or increasing the fibrosis-related gene collagen, type I, ɑ-1, and procollagen, type I, ɑ-1 production. In contrast, UA had inhibitory effects on these processes. The study also showed that both nuclear and membrane progesterone receptors play distinct roles in uterine leiomyoma pathobiology.

CONCLUSIONS

We showed that both nuclear and membrane progesterone receptors were relevant in the treatment of uterine leiomyomas, especially when combined with selective progesterone receptor modulators. Novel therapeutic approaches combining selective progesterone receptor modulators with or without direct and indirect extracellular matrix targeting through selected specifically TGF-β and SMAD3 (SMAD3, TGF-β receptor types 1 and II, Ras homolog A, vascular endothelial growth factor, collagen, type I, ɑ-1) signaling pathways could therefore be a treatment option for uterine leiomyomas.

Beadex, the Drosophila LIM only protein, is required for the growth of the larval neuromuscular junction

The appropriate growth of the neurons, accurate organization of their synapses, and successful neurotransmission are indispensable for sensorimotor activities. These processes are highly dynamic and tightly regulated. Extensive genetic, molecular, physiological, and behavioral studies have identified many molecular candidates and investigated their roles in various neuromuscular processes. In this article, we show that Beadex (Bx), the Drosophila LIM only (LMO) protein, is required for motor activities and neuromuscular growth of Drosophila. The larvae bearing Bx7, a null allele of Bx, and the RNAi-mediated neuronal-specific knockdown of Bx show drastically reduced crawling behavior, a diminished synaptic span of the neuromuscular junctions (NMJs) and an increased spontaneous neuronal firing with altered motor patterns in the central pattern generators (CPGs). Microarray studies identified multiple targets of Beadex that are involved in different cellular and molecular pathways, including those associated with the cytoskeleton and mitochondria that could be responsible for the observed neuromuscular defects. With genetic interaction studies, we further show that Highwire (Hiw), a negative regulator of synaptic growth at the NMJs, negatively regulates Bx, as the latter's deficiency was able to rescue the phenotype of the Hiw null mutant, HiwDN. Thus, our data indicate that Beadex functions downstream of Hiw to regulate the larval synaptic growth and physiology.NEW & NOTEWORTHY A novel role for Beadex (Bx) regulates the larval neuromuscular junction (NMJ) structure and function in a tissue-specific manner. Bx is expressed in a subset of Toll-6-expressing neurons and is involved in regulating synaptic span and physiology, possibly through its negative interaction with Highwire (Hiw). The findings of this study provide insights into the molecular mechanisms underlying NMJ development and function and warrant further investigation to understand the role of Bx in these processes fully.

Inhibition of mTOR differently modulates planar and subepithelial fibrogenesis in human conjunctival fibroblasts

PURPOSE

In the current investigation, the effects of the mTOR inhibitors, Rapa and Torin1 on the TGF-β2-induced conjunctival fibrogenesis were studied.

STUDY DESIGN

Experimental research.

METHODS

2D and 3D cultures of HconF were subjected to the following analyses; (1) planar proliferation evaluated by TEER (2D), (2) Seahorse metabolic analyses (2D), (3) subepithelial proliferation evaluated by the 3D spheroids' size and hardness, and (4) the mRNA expression of ECM proteins and their regulators (2D and 3D).

RESULT

Rapa or Torin1 both significantly increased planar proliferation in the non-TGF-β2-treated 2D HconF cells, but in the TGF-β2-treated cells, this proliferation was inhibited by Rapa and enhanced by Torin1. Although Rapa or Torin1 did not affect cellular metabolism in the non-TGF-β2-treated HconF cells, mTOR inhibitors significantly decreased and increased the mitochondrial respiration and the glycolytic capacity, respectively, under conditions of TGF-β2-induced fibrogenesis. Subepithelial proliferation, as evidenced by the hardness of the 3D spheroids, was markedly down-regulated by both Rapa and Torin1 independent of TGF-β2. The mRNA expressions of several ECM molecules and their regulators fluctuated in the cases of 2D vs 3D and TGF-β2 untreated vs treated cultures.

CONCLUSION

The present findings indicate that mTOR inhibitors have the ability to increase and to reduce planar and subepithelial proliferation in HconF cells, depending on the inhibitor being used.

Fibroblast Smad7 Induction Protects the Remodeling Pressure-Overloaded Heart

BACKGROUND

Cardiac fibroblast activation contributes to adverse remodeling, fibrosis, and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β (transforming growth factor-β)/Smad (small mother against decapentaplegic)-3 activation protects the pressure-overloaded heart by preserving the matrix, sustained TGF-β activation is deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF-β response in fibroblasts may be required to protect from progressive fibrosis and adverse remodeling. We hypothesized that Smad7, an inhibitory Smad that restrains TGF-β signaling, may be induced in the pressure-overloaded myocardium and may regulate fibrosis, remodeling, and dysfunction.

METHODS

The effects of myofibroblast-specific Smad7 loss were studied in a mouse model of transverse aortic constriction, using echocardiography, histological analysis, and molecular analysis. Proteomic studies in S7KO (Smad7 knockout) and overexpressing cells were used to identify fibroblast-derived mediators modulated by Smad7. In vitro experiments using cultured cardiac fibroblasts, fibroblasts populating collagen lattices, and isolated macrophages were used to dissect the molecular signals responsible for the effects of Smad7.

RESULTS

Following pressure overload, Smad7 was upregulated in cardiac myofibroblasts. TGF-β and angiotensin II stimulated fibroblast Smad7 upregulation via Smad3, whereas GDF15 (growth differentiation factor 15) induced Smad7 through GFRAL (glial cell line-derived neurotrophic factor family receptor α-like). MFS7KO (myofibroblast-specific S7KO) mice had increased mortality, accentuated systolic dysfunction and dilative remodeling, and accelerated diastolic dysfunction in response to transverse aortic constriction. Increased dysfunction in MFS7KO hearts was associated with accentuated fibrosis and increased MMP (matrix metalloproteinase)-2 activity and collagen denaturation. Secretomic analysis showed that Smad7 loss accentuates secretion of structural collagens and matricellular proteins and markedly increases MMP2 secretion. In contrast, Smad7 overexpression reduced MMP2 levels. In fibroblasts populating collagen lattices, the effects of Smad7 on fibroblast-induced collagen denaturation and pad contraction were partly mediated via MMP2 downregulation. Surprisingly, MFS7KO mice also exhibited significant macrophage expansion caused by paracrine actions of Smad7 null fibroblasts that stimulate macrophage proliferation and fibrogenic activation. Macrophage activation involved the combined effects of the fibroblast-derived matricellular proteins CD5L (CD5 antigen-like), SPARC (secreted protein acidic and rich in cysteine), CTGF (connective tissue growth factor), ECM1 (extracellular matrix protein 1), and TGFBI (TGFB induced).

CONCLUSIONS

The antifibrotic effects of Smad7 in the pressure-overloaded heart protect from dysfunction and involve not only reduction in collagen deposition but also suppression of MMP2-mediated matrix denaturation and paracrine effects that suppress macrophage activation through inhibition of matricellular proteins.

Pirfenidone Prevents Heart Fibrosis during Chronic Chagas Disease Cardiomyopathy

Cardiac fibrosis is a severe outcome of Chagas disease (CD), caused by the protozoan Trypanosoma cruzi. Clinical evidence revealed a correlation between fibrosis levels with impaired cardiac performance in CD patients. Therefore, we sought to analyze the effect of inhibitors of TGF-β (pirfenidone), p38-MAPK (losmapimod) and c-Jun (SP600125) on the modulation of collagen deposition in cardiac fibroblasts (CF) and in vivo models of T. cruzi chronic infection. Sirius Red/Fast Green dye was used to quantify both collagen expression and total protein amount, assessing cytotoxicity. The compounds were also used to treat C57/Bl6 mice chronically infected with T. cruzi, Brazil strain. We identified an anti-fibrotic effect in vitro for pirfenidone (TGF-β inhibitor, IC50 114.3 μM), losmapimod (p38 inhibitor, IC50 17.6 μM) and SP600125 (c-Jun inhibitor, IC50 3.9 μM). This effect was independent of CF proliferation since these compounds do not affect T. cruzi-induced host cell multiplication as measured by BrdU incorporation. Assays of chronic infection of mice with T. cruzi have shown a reduction in heart collagen by pirfenidone. These results propose a novel approach to fibrosis therapy in CD, with the prospect of repurposing pirfenidone to prevent the onset of ECM accumulation in the hearts of the patients.

The Role of Neuromodulation and Potential Mechanism in Regulating Heterotopic Ossification

Heterotopic ossification (HO) is a pathological process characterized by the aberrant formation of bone in muscles and soft tissues. It is commonly triggered by traumatic brain injury, spinal cord injury, and burns. Despite a wide range of evidence underscoring the significance of neurogenic signals in proper bone remodeling, a clear understanding of HO induced by nerve injury remains rudimentary. Recent studies suggest that injury to the nervous system can activate various signaling pathways, such as TGF-β, leading to neurogenic HO through the release of neurotrophins. These pathophysiological changes lay a robust groundwork for the prevention and treatment of HO. In this review, we collected evidence to elucidate the mechanisms underlying the pathogenesis of HO related to nerve injury, aiming to enhance our understanding of how neurological repair processes can culminate in HO.

Verteporfin inhibits TGF-β signaling by disrupting the Smad2/3-Smad4 interaction

Transforming growth factor-β (TGF-β) signaling plays a crucial role in pathogenesis, such as accelerating tissue fibrosis and promoting tumor development at the later stages of tumorigenesis by promoting epithelial-mesenchymal transition (EMT), cancer cell migration, and invasion. Targeting TGF-β signaling is a promising therapeutic approach, but nonspecific inhibition may result in adverse effects. In this study, we focus on the Smad2/3-Smad4 complex, a key component in TGF-β signaling transduction, as a potential target for cancer therapy. Through a phase-separated condensate-aided biomolecular interaction system, we identified verteporfin (VP) as a small-molecule inhibitor that specifically targets the Smad2/3-Smad4 interaction. VP effectively disrupted the interaction between Smad2/3 and Smad4 and thereby inhibited canonical TGF-β signaling, but not the interaction between Smad1 and Smad4 in bone morphogenetic protein (BMP) signaling. Furthermore, VP exhibited inhibitory effects on TGF-β-induced EMT and cell migration. Our findings indicate a novel approach to develop protein-protein interaction inhibitors of the canonical TGF-β signaling pathway for treatments of related diseases.

TGF-β signaling: critical nexus of fibrogenesis and cancer

The transforming growth factor-beta (TGF-β) signaling pathway is a vital regulator of cell proliferation, differentiation, apoptosis, and extracellular matrix production. It functions through canonical SMAD-mediated processes and noncanonical pathways involving MAPK cascades, PI3K/AKT, Rho-like GTPases, and NF-κB signaling. This intricate signaling system is finely tuned by interactions between canonical and noncanonical pathways and plays key roles in both physiologic and pathologic conditions including tissue homeostasis, fibrosis, and cancer progression. TGF-β signaling is known to have paradoxical actions. Under normal physiologic conditions, TGF-β signaling promotes cell quiescence and apoptosis, acting as a tumor suppressor. In contrast, in pathological states such as inflammation and cancer, it triggers processes that facilitate cancer progression and tissue remodeling, thus promoting tumor development and fibrosis. Here, we detail the role that TGF-β plays in cancer and fibrosis and highlight the potential for future theranostics targeting this pathway.

Role of Protein Phosphatases in Tumor Angiogenesis: Assessing PP1, PP2A, PP2B and PTPs Activity

Tumor angiogenesis, the formation of new blood vessels to support tumor growth and metastasis, is a complex process regulated by a multitude of signaling pathways. Dysregulation of signaling pathways involving protein kinases has been extensively studied, but the role of protein phosphatases in angiogenesis within the tumor microenvironment remains less explored. However, among angiogenic pathways, protein phosphatases play critical roles in modulating signaling cascades. This review provides a comprehensive overview of the involvement of protein phosphatases in tumor angiogenesis, highlighting their diverse functions and mechanisms of action. Protein phosphatases are key regulators of cellular signaling pathways by catalyzing the dephosphorylation of proteins, thereby modulating their activity and function. This review aims to assess the activity of the protein tyrosine phosphatases and serine/threonine phosphatases. These phosphatases exert their effects on angiogenic signaling pathways through various mechanisms, including direct dephosphorylation of angiogenic receptors and downstream signaling molecules. Moreover, protein phosphatases also crosstalk with other signaling pathways involved in angiogenesis, further emphasizing their significance in regulating tumor vascularization, including endothelial cell survival, sprouting, and vessel maturation. In conclusion, this review underscores the pivotal role of protein phosphatases in tumor angiogenesis and accentuate their potential as therapeutic targets for anti-angiogenic therapy in cancer.

Lrba participates in the differentiation of IgA+ B lymphocytes through TGFβR signaling

Introduction

Lrba is a cytoplasmic protein involved in vesicular trafficking. Lrba-deficient (Lrba-/-) mice exhibit substantially higher levels of IgA in both serum and feces than wild-type (WT) mice. Transforming growth factor β1 (TGFβ1) and its receptors (TGFβR I and II) is essential for differentiating IgA+ B cells. Furthermore, increased IgA production suggests a potential connection between Lrba and the TGFβR signaling pathway in IgA production. However, the specific function of Lrba in B cell biology remains unknown.

Aim

Given the increased IgA levels in Lrba-/- mice, the goal in this work was to explore the lymph organs where the switch to IgA occurs, and if TGFβR function is affected.

Methods

Non-immunized Lrba-/- mice were compared with Lrba+/+ mice. IgA levels in the serum and feces, as well as during peripheral B cell development, were determined. IgA+ B cells and plasma cells were assessed in the small intestine and secondary lymphoid organs, such as the spleen, mesenteric lymph nodes, and Peyer's patches. The TGFβR signaling pathway was evaluated by determining the expression of TGFβR on B cells. Additionally, SMAD2 phosphorylation was measured under basal conditions and in response to recombinant TGFβ. Finally, confocal microscopy was performed to investigate a possible interaction between Lrba and TGFβR in B cells.

Results

Lrba-/- mice exhibited significantly higher levels of circulating IgA, IgA+ B, and plasma cells than in peripheral lymphoid organs those in WT mice. TGFβR expression on the membrane of B cells was similar in both Lrba-/- and Lrba+/+ mice. However, intracellular TGFβR expression was reduced in Lrba-/- mice. SMAD2 phosphorylation showed increased levels under basal conditions; stimulation with recombinant TGFβ elicited a poorer response than in that in Lrba+/+ B cells. Finally, we found that Lrba colocalizes with TGFβR in B cells.

Conclusion

Lrba is essential in controlling TGFβR signaling, subsequently regulating SMAD2 phosphorylation on B cells. This mechanism may explain the increased differentiation of IgA+ B cells and production of IgA-producing plasma cells.

Oncostatin M suppresses bone morphogenetic protein-4-induced osteoprotegerin synthesis in MC3T3-E1 osteoblast-like cells: p70 S6 kinase attenuation

Evidence is accumulating that osteal macrophages, in addition to bone-resorbing osteoclasts and bone-forming osteoblasts, participate vitally in bone remodeling process. Oncostatin M (OSM), an inflammatory cytokine belonging to interleukin-6 superfamily, is recognized as an essential factor secreted by osteal macrophages to orchestrate bone remodeling. Osteoprotegerin (OPG) produced by osteoblasts regulates osteoclastogenesis. We have reported that bone morphogenetic protein-4 (BMP-4) stimulates OPG synthesis in MC3T3-E1 osteoblast-like cells, and that SMAD1/5/8(9), p38 mitogen-activated protein kinase (MAPK), and p70 S6 kinase are involved in the OPG synthesis. The present study aims to investigate the effect of OSM on the synthesis of OPG stimulated by BMP-4 in osteoblasts. OSM suppressed the release and the mRNA expression of OPG upregulated by BMP-4 in MC3T3-E1 cells. Neither the BMP-4-induced phosphorylation of SMAD1/5/9 nor that of p38 MAPK was affected by OSM. On the other hand, the phosphorylation of p70 S6 kinase stimulated by BMP-4 was considerably suppressed by OSM. These results strongly suggest that OSM suppresses the BMP-4-stimulated OPG synthesis via inhibition of the p70 S6 kinase-mediated pathway in osteoblast-like cells.

Comprehensive molecular interaction map of TGFβ induced epithelial to mesenchymal transition in breast cancer

Breast cancer is one of the prevailing cancers globally, with a high mortality rate. Metastatic breast cancer (MBC) is an advanced stage of cancer, characterised by a highly nonlinear, heterogeneous process involving numerous singling pathways and regulatory interactions. Epithelial-mesenchymal transition (EMT) emerges as a key mechanism exploited by cancer cells. Transforming Growth Factor-β (TGFβ)-dependent signalling is attributed to promote EMT in advanced stages of breast cancer. A comprehensive regulatory map of TGFβ induced EMT was developed through an extensive literature survey. The network assembled comprises of 312 distinct species (proteins, genes, RNAs, complexes), and 426 reactions (state transitions, nuclear translocations, complex associations, and dissociations). The map was developed by following Systems Biology Graphical Notation (SBGN) using Cell Designer and made publicly available using MINERVA ( http://35.174.227.105:8080/minerva/?id=Metastatic_Breast_Cancer_1 ). While the complete molecular mechanism of MBC is still not known, the map captures the elaborate signalling interplay of TGFβ induced EMT-promoting MBC. Subsequently, the disease map assembled was translated into a Boolean model utilising CaSQ and analysed using Cell Collective. Simulations of these have captured the known experimental outcomes of TGFβ induced EMT in MBC. Hub regulators of the assembled map were identified, and their transcriptome-based analysis confirmed their role in cancer metastasis. Elaborate analysis of this map may help in gaining additional insights into the development and progression of metastatic breast cancer.

Endocardial HDAC3 is required for myocardial trabeculation

Failure of proper ventricular trabeculation is often associated with congenital heart disease. Support from endocardial cells, including the secretion of extracellular matrix and growth factors is critical for trabeculation. However, it is poorly understood how the secretion of extracellular matrix and growth factors is initiated and regulated by endocardial cells. We find that genetic knockout of histone deacetylase 3 in the endocardium in mice results in early embryo lethality and ventricular hypotrabeculation. Single cell RNA sequencing identifies significant downregulation of extracellular matrix components in histone deacetylase 3 knockout endocardial cells. Secretome from cultured histone deacetylase 3 knockout mouse cardiac endothelial cells lacks transforming growth factor ß3 and shows significantly reduced capacity in stimulating cultured cardiomyocyte proliferation, which is remarkably rescued by transforming growth factor ß3 supplementation. Mechanistically, we identify that histone deacetylase 3 knockout induces transforming growth factor ß3 expression through repressing microRNA-129-5p. Our findings provide insights into the pathogenesis of congenital heart disease and conceptual strategies to promote myocardial regeneration.

Exploring unconventional targets in myofibroblast transdifferentiation outside classical TGF-β signaling in renal fibrosis

We propose that the key initiators of renal fibrosis are myofibroblasts which originate from four predominant sources-fibroblasts, pericytes, endothelial cells and macrophages. Increased accumulation of renal interstitial myofibroblasts correlates with an increase in collagen, fibrillar proteins, and fibrosis severity. The canonical TGF-β pathway, signaling via Smad proteins, is the central molecular hub that initiates these cellular transformations. However, directly targeting these classical pathway molecules has proven challenging due their integral roles in metabolic process, and/or non-sustainable effects involving compensatory cross-talk with TGF-β. This review explores recently discovered alternative molecular targets that drive transdifferentiation into myofibroblasts. Discovering targets outside of the classical TGF-β/Smad pathway is crucial for advancing antifibrotic therapies, and strategically targeting the development of myofibroblasts offers a promising approach to control excessive extracellular matrix deposition and impede fibrosis progression.

Driver Mutations in Pancreatic Cancer and Opportunities for Targeted Therapy

Pancreatic cancer is the sixth leading cause of cancer-related mortality globally. As the most common form of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC) represents up to 95% of all pancreatic cancer cases, accounting for more than 300,000 deaths annually. Due to the lack of early diagnoses and the high refractory response to the currently available treatments, PDAC has a very poor prognosis, with a 5-year overall survival rate of less than 10%. Targeted therapy and immunotherapy are highly effective and have been used for the treatment of many types of cancer; however, they offer limited benefits in pancreatic cancer patients due to tumor-intrinsic and extrinsic factors that culminate in drug resistance. The identification of key factors responsible for PDAC growth and resistance to different treatments is highly valuable in developing new effective therapeutic strategies. In this review, we discuss some molecules which promote PDAC initiation and progression, and their potential as targets for PDAC treatment. We also evaluate the challenges associated with patient outcomes in clinical trials and implications for future research.

High expression of SLC7A1 in high-grade serous ovarian cancer promotes tumor progression and is involved in MAPK/ERK pathway and EMT

Our previous studies have shown that upregulation of SLC7A1 in epithelial ovarian cancer (EOC) tumor cells significantly increases cancer cell proliferation, migration, and cisplatin resistance; however, the molecular mechanism by which SLC7A1 functions in EOC remains unknown. In later studies, we found that SLC7A1 is also highly expressed in the interstitial portion of high-grade serous ovarian cancer (HGSOC), but the significance of this high expression in the interstitial remains unclear. Here, we showed the Interstitial high expression of SLC7A1 in HGSOC by immunohistochemistry. SLC7A1 enriched in cancer-associated fibroblasts (CAFs) was upregulated by TGF-β1. Transwell assay, scratch assay, cck8 assay and cell adhesion assay showed that SLC7A1 highly expressed in CAFs promoted tumor cells invasion, migration and metastasis in vitro. The effect of SLC7A1 on MAPK and EMT pathway proteins in ovarian cancer (OC) was verified by RNA sequencing and western blotting. Overexpression of SLC7A1 in OC is involved in MAPK/ ERK pathway and EMT. In general, in HGSOC, CAFs overexpressing SLC7A1 supported the migration and invasion of tumor cells; SLC7A1 is highly expressed in ovarian cancer and is involved in ERK phosphorylation and EMT signaling in MAPK signaling pathway. This suggests that SLC7A1 may be a potential therapeutic target for OC metastasis.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Dissecting the shared genetic architecture between Alzheimer's disease and frailty: a cross-trait meta-analyses of genome-wide association studies

Introduction: Frailty is the most common medical condition affecting the aging population, and its prevalence increases in the population aged 65 or more. Frailty is commonly diagnosed using the frailty index (FI) or frailty phenotype (FP) assessments. Observational studies have indicated the association of frailty with Alzheimer's disease (AD). However, the shared genetic and biological mechanism of these comorbidity has not been studied. Methods: To assess the genetic relationship between AD and frailty, we examined it at single nucleotide polymorphism (SNP), gene, and pathway levels. Results: Overall, 16 genome-wide significant loci (15 unique loci) (p meta-analysis < 5 × 10-8) and 22 genes (21 unique genes) were identified between AD and frailty using cross-trait meta-analysis. The 8 shared loci implicated 11 genes: CLRN1-AS1, CRHR1, FERMT2, GRK4, LINC01929, LRFN2, MADD, RP11-368P15.1, RP11-166N6.2, RNA5SP459, and ZNF652 between AD and FI, and 8 shared loci between AD and FFS implicated 11 genes: AFF3, C1QTNF4, CLEC16A, FAM180B, FBXL19, GRK4, LINC01104, MAD1L1, RGS12, ZDHHC5, and ZNF521. The loci 4p16.3 (GRK4) was identified in both meta-analyses. The colocalization analysis supported the results of our meta-analysis in these loci. The gene-based analysis revealed 80 genes between AD and frailty, and 4 genes were initially identified in our meta-analyses: C1QTNF4, CRHR1, MAD1L1, and RGS12. The pathway analysis showed enrichment for lipoprotein particle plasma, amyloid fibril formation, protein kinase regulator, and tau protein binding. Conclusion: Overall, our results provide new insights into the genetics of AD and frailty, suggesting the existence of non-causal shared genetic mechanisms between these conditions.

Tgfb1 deficiency impairs the self-renewal capacity of murine hematopoietic stem/progenitor cells in vivo

Transforming growth factor β1 (TGFB1) refers to a pleiotropic cytokine exerting contrasting roles in hematopoietic stem cells (HSCs) functions in vitro and in vivo. However, the understanding of hematopoiesis in vivo, when TGFB1 is constantly deactivated, is still unclear, mainly due to significant embryonic lethality and the emergence of a fatal inflammatory condition, which makes doing these investigations challenging. Our study aims to find the specific role of TGFB1 in regulating hematopoiesis in vivo. We engineered mice strains (Vav1 or Mx1 promoter-driven TGFB1 knockout) with conditional knockout of TGFB1 to study its role in hematopoiesis in vivo. In fetal and adult hematopoiesis, TGFB1 KO mice displayed deficiency and decreased self-renewal capacity of HSCs with myeloid-biased differentiation. The results were different from the regulating role of TGFB1 in vitro. Additionally, our results showed that TGFB1 deficiency from fetal hematopoiesis stage caused more severe defect of HSCs than in the adult stage. Mechanistically, our findings identified TGFB1-SOX9-FOS/JUNB/TWIST1 signal axis as an essential regulating pathway in HSCs homeostasis. Our study may provide a scientific basis for clinical HSC transplantation and expansion.

HER2 phosphorylation induced by TGF-β promotes mammary morphogenesis and breast cancer progression

Transforming growth factor β (TGF-β) and HER2 signaling collaborate to promote breast cancer progression. However, their molecular interplay is largely unclear. TGF-β can activate mitogen-activated protein kinase (MAPK) and AKT, but the underlying mechanism is not fully understood. In this study, we report that TGF-β enhances HER2 activation, leading to the activation of MAPK and AKT. This process depends on the TGF-β type I receptor TβRI kinase activity. TβRI phosphorylates HER2 at Ser779, promoting Y1248 phosphorylation and HER2 activation. Mice with HER2 S779A mutation display impaired mammary morphogenesis, reduced ductal elongation, and branching. Furthermore, wild-type HER2, but not S779A mutant, promotes TGF-β-induced epithelial-mesenchymal transition, cell migration, and lung metastasis of breast cells. Increased HER2 S779 phosphorylation is observed in human breast cancers and positively correlated with the activation of HER2, MAPK, and AKT. Our findings demonstrate the crucial role of TGF-β-induced S779 phosphorylation in HER2 activation, mammary gland development, and the pro-oncogenic function of TGF-β in breast cancer progression.

Large-scale phosphoproteomics reveals activation of the MAPK/GADD45β/P38 axis and cell cycle inhibition in response to BMP9 and BMP10 stimulation in endothelial cells

BACKGROUND

BMP9 and BMP10 are two major regulators of vascular homeostasis. These two ligands bind with high affinity to the endothelial type I kinase receptor ALK1, together with a type II receptor, leading to the direct phosphorylation of the SMAD transcription factors. Apart from this canonical pathway, little is known. Interestingly, mutations in this signaling pathway have been identified in two rare cardiovascular diseases, hereditary hemorrhagic telangiectasia and pulmonary arterial hypertension.

METHODS

To get an overview of the signaling pathways modulated by BMP9 and BMP10 stimulation in endothelial cells, we employed an unbiased phosphoproteomic-based strategy. Identified phosphosites were validated by western blot analysis and regulated targets by RT-qPCR. Cell cycle analysis was analyzed by flow cytometry.

RESULTS

Large-scale phosphoproteomics revealed that BMP9 and BMP10 treatment induced a very similar phosphoproteomic profile. These BMPs activated a non-canonical transcriptional SMAD-dependent MAPK pathway (MEKK4/P38). We were able to validate this signaling pathway and demonstrated that this activation required the expression of the protein GADD45β. In turn, activated P38 phosphorylated the heat shock protein HSP27 and the endocytosis protein Eps15 (EGF receptor pathway substrate), and regulated the expression of specific genes (E-selectin, hyaluronan synthase 2 and cyclooxygenase 2). This study also highlighted the modulation in phosphorylation of proteins involved in transcriptional regulation (phosphorylation of the endothelial transcription factor ERG) and cell cycle inhibition (CDK4/6 pathway). Accordingly, we found that BMP10 induced a G1 cell cycle arrest and inhibited the mRNA expression of E2F2, cyclinD1 and cyclinA1.

CONCLUSIONS

Overall, our phosphoproteomic screen identified numerous proteins whose phosphorylation state is impacted by BMP9 and BMP10 treatment, paving the way for a better understanding of the molecular mechanisms regulated by BMP signaling in vascular diseases.

Endocardial HDAC3 is required for myocardial trabeculation

BACKGROUND

Trabeculation, a key process in early heart development, is the formation of myocardial trabecular meshwork. The failure of trabeculation often leads to embryonic lethality. Support from endocardial cells, including the secretion of extracellular matrix (ECM) and growth factors is critical for trabeculation; however, it is unknown how the secretion of ECM and growth factors is initiated and regulated by endocardial cells.

METHODS

Various cellular and mouse models in conjunction with biochemical and molecular tools were employed to study the role of histone deacetylase 3 (HDAC3) in the developing endocardium.

RESULTS

We found that genetic deletion of Hdac3 in endocardial cells in mice resulted in early embryo lethality presenting as a hypotrabeculation cardiac phenotype. Single cell RNA sequencing identified several ECM components including collagens that were significantly downregulated in Hdac3 knockout (KO) endocardial cells. When cultured with supernatant from Hdac3 KO mouse cardiac endothelial cells (MCECs), wild-type mouse embryonic cardiomyocytes showed decreased proliferation, suggesting that growth signaling from Hdac3 KO MCECs is disrupted. Subsequent transcriptomic analysis revealed that transforming growth factor β3 (TGFβ3) was significantly downregulated in Hdac3 KO MCECs and Hdac3 cardiac endothelial KO hearts. Mechanistically, we identified that microRNA (miR)-129-5p was significantly upregulated in Hdac3 KO MCECs and Hdac3 cardiac endothelial KO hearts. Overexpression of miR-129-5p repressed Tgfβ3 expression in wild-type MCECs, whereas knockdown of miR-129-5p restored Tgfβ3 expression in Hdac3 KO MCECs.

CONCLUSION

Our findings reveal a critical signaling pathway in which endocardial HDAC3 promotes trabecular myocardium growth by stimulating TGFβ signaling through repressing miR-129-5p, providing novel insights into the etiology of congenital heart disease and conceptual strategies to promote myocardial regeneration.

Isorhamnetin suppresses the epithelial-mesenchymal transition of the retinal pigment epithelium both in vivo and in vitro through Nrf2-dependent AKT/GSK-3β pathway

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly worldwide. Multiple studies have shown that epithelial-mesenchymal transition (EMT) plays a pivotal role in the pathogenesis of AMD. Isorhamnetin (Isor) is a flavonoid compound that inhibits EMT in tumor cells. However, whether it can also attenuate EMT in the retinal pigment epithelium (RPE) is unknown. Therefore, our study was designed to probe the possible impact of Isor on EMT process in both mouse retina and ARPE-19 cells. C57BL/6 mice were utilized to establish a dry AMD model. Isor and LCZ (a mixture of luteine/β-carotene/zinc gluconate) were administered orally for 3 months. The effects of Isor on the retina were evaluated using fundus autofluorescence, optical coherence tomography, and transmission electron microscopy. Transwell and wound healing assay were employed to assess ARPE-19 cell migration. Western blotting and immunofluorescence were used to measure the protein expressions associated with EMT, Nrf2 and AKT/GSK-3β pathway. The findings indicated that Isor alleviated dry AMD-like pathological changes in vehicle mice retina, inhibited the migration of Ox-LDL-treated ARPE-19 cells, and repressed the EMT processes in vivo and in vitro. Furthermore, Isor activated Nrf2 pathway and deactivated AKT/GSK-3β pathway in both vehicle mice and ARPE-19 cells. Interestingly, when Nrf2 siRNA was transfected into ARPE-19 cells, the inhibitory effect of Isor on EMT and AKT/GSK-3β pathway was attenuated. These results suggested that Isor inhibited EMT processes via Nrf2-dependent AKT/GSK-3β pathway and is a promising candidate for dry AMD treatment.

The Activation of the Fibrodysplasia Ossificans Progressiva-Inducing ALK2-R206H Mutant Depends on the Distinct Homo-Oligomerization Patterns of ACVR2B and ACVR2A

Mutations in activin-like kinase 2 (ALK2), e.g., ALK2-R206H, induce aberrant signaling to SMAD1/5/8, leading to Fibrodysplasia Ossificans Progressiva (FOP). In spite of extensive studies, the underlying mechanism is still unclear. Here, we quantified the homomeric and heteromeric interactions of ACVR2A, ACVR2B, ALK2-WT, and ALK2-R206H by combining IgG-mediated immobilization of one receptor with fluorescence recovery after photobleaching (FRAP) measurements on the lateral diffusion of a co-expressed receptor. ACVR2B formed stable homomeric complexes that were enhanced by Activin A (ActA), while ACVR2A required ActA for homodimerization. ALK2-WT, but not ALK2-R206H, exhibited homomeric complexes unaffected by ActA. ACVR2B formed ActA-enhanced heterocomplexes with ALK2-R206H or ALK2-WT, while ACVR2A interacted mainly with ALK2-WT. The extent of the homomeric complex formation of ACVR2A or ACVR2B was reflected in their ability to induce the oligomerization of ALK2-R206H and ALK2-WT. Thus, ACVR2B, which forms dimers without ligand, induced ActA-independent ALK2-R206H clustering but required ActA for enhancing the oligomerization of the largely dimeric ALK2-WT. In contrast, ACVR2A, which undergoes homodimerization in response to ActA, required ActA to induce ALK2-R206H oligomerization. To investigate whether these interactions are translated into signaling, we studied signaling by the FOP-inducing hyperactive ALK2-R206H mutant, with ALK2-WT signaling as control. The activation of SMAD1/5/8 signaling in cells expressing ALK2-R206H alone or together with ACVR2A or ACVR2B was measured by blotting for pSMAD1/5/8 and by transcriptional activation assays using BRE-Luc reporter. In line with the biophysical studies, ACVR2B activated ALK2-R206H without ligand, while activation by ACVR2A was weaker and required ActA. We propose that the homodimerization of ACVR2B or ACVR2A dictates their ability to recruit ALK2-R206H into higher complexes, enabling the homomeric interactions of ALK2-R206H receptors and, subsequently, their activation.

Inhibition of anti-tumor immunity by melanoma cell-derived Activin-A depends on STING

The transforming growth factor-β (TGF-β) family member activin A (hereafter Activin-A) is overexpressed in many cancer types, often correlating with cancer-associated cachexia and poor prognosis. Activin-A secretion by melanoma cells indirectly impedes CD8+ T cell-mediated anti-tumor immunity and promotes resistance to immunotherapies, even though Activin-A can be proinflammatory in other contexts. To identify underlying mechanisms, we here analyzed the effect of Activin-A on syngeneic grafts of Braf mutant YUMM3.3 mouse melanoma cells and on their microenvironment using single-cell RNA sequencing. We found that the Activin-A-induced immune evasion was accompanied by a proinflammatory interferon signature across multiple cell types, and that the associated increase in tumor growth depended at least in part on pernicious STING activity within the melanoma cells. Besides corroborating a role for proinflammatory signals in facilitating immune evasion, our results suggest that STING holds considerable potential as a therapeutic target to mitigate tumor-promoting Activin-A signaling at least in melanoma.

The TGF-β Family in Glioblastoma

Members of the transforming growth factor β (TGF-β) family have been implicated in the biology of several cancers. In this review, we focus on the role of TGFβ and bone morphogenetic protein (BMP) signaling in glioblastoma. Glioblastoma (GBM) is the most common malignant brain tumor in adults; it presents at a median age of 64 years, but can occur at any age, including childhood. Unfortunately, there is no cure, and even patients undergoing current treatments (surgical resection, radiotherapy, and chemotherapy) have a median survival of 15 months. There is a great need to identify new therapeutic targets to improve the treatment of GBM patients. TGF-βs signaling promotes tumorigenesis in glioblastoma, while BMPs suppress tumorigenic potential by inducing tumor cell differentiation. In this review, we discuss the actions of TGF-βs and BMPs on cancer cells as well as in the tumor microenvironment, and their use in potential therapeutic intervention.

Cholesterol modulates type I/II TGF-β receptor complexes and alters the balance between Smad and Akt signaling in hepatocytes

Cholesterol mediates membrane compartmentalization, affecting signaling via differential distribution of receptors and signaling mediators. While excessive cholesterol and aberrant transforming growth factor-β (TGF-β) signaling characterize multiple liver diseases, their linkage to canonical vs. non-canonical TGF-β signaling remained unclear. Here, we subjected murine hepatocytes to cholesterol depletion (CD) or enrichment (CE), followed by biophysical studies on TGF-β receptor heterocomplex formation, and output to Smad2/3 vs. Akt pathways. Prior to ligand addition, raft-dependent preformed heteromeric receptor complexes were observed. Smad2/3 phosphorylation persisted following CD or CE. CD enhanced phospho-Akt (pAkt) formation by TGF-β or epidermal growth factor (EGF) at 5 min, while reducing it at later time points. Conversely, pAkt formation by TGF-β or EGF was inhibited by CE, suggesting a direct effect on the Akt pathway. The modulation of the balance between TGF-β signaling to Smad2/3 vs. pAkt (by TGF-β or EGF) has potential implications for hepatic diseases and malignancies.

The Interplay of TGF-β1 and Cholesterol Orchestrating Hepatocyte Cell Fate, EMT, and Signals for HSC Activation

BACKGROUND & AIMS

Transforming growth factor-β1 (TGF-β1) plays important roles in chronic liver diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD involves various biological processes including dysfunctional cholesterol metabolism and contributes to progression to metabolic dysfunction-associated steatohepatitis and hepatocellular carcinoma. However, the reciprocal regulation of TGF-β1 signaling and cholesterol metabolism in MASLD is yet unknown.

METHODS

Changes in transcription of genes associated with cholesterol metabolism were assessed by RNA sequencing of murine hepatocyte cell line (alpha mouse liver 12/AML12) and mouse primary hepatocytes treated with TGF-β1. Functional assays were performed on AML12 cells (untreated, TGF-β1 treated, or subjected to cholesterol enrichment [CE] or cholesterol depletion [CD]), and on mice injected with adenovirus-associated virus 8-control/TGF-β1.

RESULTS

TGF-β1 inhibited messenger RNA expression of several cholesterol metabolism regulatory genes, including rate-limiting enzymes of cholesterol biosynthesis in AML12 cells, mouse primary hepatocytes, and adenovirus-associated virus-TGF-β1-treated mice. Total cholesterol levels and lipid droplet accumulation in AML12 cells and liver tissue also were reduced upon TGF-β1 treatment. Smad2/3 phosphorylation after 2 hours of TGF-β1 treatment persisted after CE or CD and was mildly increased after CD, whereas TGF-β1-mediated AKT phosphorylation (30 min) was inhibited by CE. Furthermore, CE protected AML12 cells from several effects mediated by 72 hours of incubation with TGF-β1, including epithelial-mesenchymal transition, actin polymerization, and apoptosis. CD mimicked the outcome of long-term TGF-β1 administration, an effect that was blocked by an inhibitor of the type I TGF-β receptor. In addition, the supernatant of CE- or CD-treated AML12 cells inhibited or promoted, respectively, the activation of LX-2 hepatic stellate cells.

CONCLUSIONS

TGF-β1 inhibits cholesterol metabolism whereas cholesterol attenuates TGF-β1 downstream effects in hepatocytes.

Adipose-derived stem cells repair radiation-induced chronic lung injury via inhibiting TGF-β1/Smad 3 signaling pathway

To investigate the effect of adipose-derived stem cells (ASCs) transplantation on radiation-induced lung injury (RILI), Sprague-Dawley rats were divided into phosphate-buffered saline (PBS) group, ASCs group, Radiation + PBS group, and Radiation + ASCs group. Radiation + PBS and Radiation + ASCs groups received single dose of 30 Gy X-ray radiation to the right chest. The Radiation + PBS group received 1 mL PBS suspension and Radiation + ASCs group received 1 mL PBS suspension containing 1 × 107 CM-Dil-labeled ASCs. The right lung tissue was collected on Days 30, 90, and 180 after radiation. Hematoxylin-eosin and Masson staining were performed to observe the pathological changes and collagen fiber content in the lung tissue. Immunohistochemistry (IHC) and western blot (WB) were used to detect levels of fibrotic markers collagen I (Collal), fibronectin (FN), as well as transforming growth factor-β1 (TGF-β1), p-Smad 3, and Smad 3. Compared with the non-radiation groups, the radiation groups showed lymphocyte infiltration on Day 30 after irradiation and thickened incomplete alveolar walls, collagen deposition, and fibroplasia on Days 90 and 180. ASCs relieved these changes on Day 180 (Masson staining, P = 0.0022). Compared with Radiation + PBS group, on Day 180 after irradiation, the Radiation + ASCs group showed that ASCs could significantly decrease the expressions of fibrosis markers Collal (IHC: P = 0.0022; WB: P = 0.0087) and FN (IHC: P = 0.0152; WB: P = 0.026) and inhibit the expressions of TGF-β1 (IHC: P = 0.026; WB: P = 0.0152) and p-Smad 3 (IHC: P = 0.0043; WB: P = 0.0087) in radiation-induced injured lung tissue. These indicated that ASCs could relieve RILI by inhibiting TGF-β1/Smad 3 signaling pathway.

The mechanisms and functions of TGF-β1 in tendon healing

Tendon injury accounts for 30% of musculoskeletal diseases and often leads to disability, pain, healthcare cost, and lost productivity. Following injury to tendon, tendon healing proceeds via three overlapping healing processes. However, due to the structural defects of the tendon itself, the tendon healing process is characterized by the formation of excessive fibrotic scar tissue, and injured tendons rarely return to native tendons, which can easily contribute to tendon reinjury. Moreover, the resulting fibrous scar is considered to be a precipitating factor for subsequent degenerative tendinopathy. Despite this, therapies are almost limited because underlying molecular mechanisms during tendon healing are still unknown. Transforming Growth Factor-β1 (TGF-β1) is known as one of most potent profibrogenic factors during tendon healing process. However, blockage TGF-β1 fails to effectively enhance tendon healing. A detailed understanding of real abilities of TGF-β1 involved in tendon healing can bring promising perspectives for therapeutic value that improve the tendon healing process. Thus, in this review, we describe recent efforts to identify and characterize the roles and mechanisms of TGF-β1 involved at each stage of the tendon healing and highlight potential roles of TGF-β1 leading to the fibrotic response to tendon injury.

The Evolving Pathways of the Efficacy of and Resistance to CDK4/6 Inhibitors in Breast Cancer

The approval of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) has remarkably improved the survival outcomes of patients with advanced hormone receptor-positive (HR+) breast cancer (BC), becoming the new standard of care treatment in these patients. Despite the efficacy of this therapeutic combination, intrinsic and acquired resistance inevitably occurs and represents a major clinical challenge. Several mechanisms associated with resistance to CDK4/6i have been identified, including both cell cycle-related and cell cycle-nonspecific mechanisms. This review discusses new insights underlying the mechanisms of action of CDK4/6i, which are more far-reaching than initially thought, and the currently available evidence of the mechanisms of resistance to CDK4/6i in BC. Finally, it highlights possible treatment strategies to improve CDK4/6i efficacy, summarizing the most relevant clinical data on novel combination therapies involving CDK4/6i.

Changes in the Expression of TGF-Beta Regulatory Pathway Genes Induced by Vitamin D in Patients with Relapsing-Remitting Multiple Sclerosis

Vitamin D is an environmental factor related to multiple sclerosis that plays a significant role in immune regulation. TGF-β is a superfamily of cytokines with an important dual effect on the immune system. TGF-β inhibits the Th1 response while facilitating the preservation of regulatory T cells (FOXP3+) in an immunoregulatory capacity. However, when IL-6 is present, it stimulates the Th17 response. Our aim was to analyze the regulatory effect of vitamin D on the in vivo TGF-β signaling pathway in patients with relapsing-remitting multiple sclerosis (RRMS). A total of 21 patients with vitamin D levels < 30 ng/mL were recruited and supplemented with oral vitamin D. All patients were receiving disease-modifying therapy, with the majority being on natalizumab. Expression of SMAD7, ERK1, ZMIZ1, BMP2, BMPRII, BMP4, and BMP5 was measured in CD4+ lymphocytes isolated from peripheral blood at baseline and one and six months after supplementation. SMAD7 was overexpressed at six months with respect to baseline and month one. ERK1 was overexpressed at six months with respect to month one of treatment. No significant differences in expression were observed for the remaining genes. No direct correlation was found with serum vitamin D levels. BMPRII expression changed differentially in non-natalizumab- versus natalizumab-treated patients. Changes were observed in the expression of ERK1, BMP2, and BMP5 based on disease activity measured using the Rio-Score, BMP2 in patients who had relapses, and BMP5 in those whose EDSS worsened. Our results suggest indirect regulation of vitamin D in TGF-β pathway genes in patients with RRMS.

Recent Updates on Viral Oncogenesis: Available Preventive and Therapeutic Entities

Human viral oncogenesis is a complex phenomenon and a major contributor to the global cancer burden. Several recent findings revealed cellular and molecular pathways that promote the development and initiation of malignancy when viruses cause an infection. Even, antiviral treatment has become an approach to eliminate the viral infections and prevent the activation of oncogenesis. Therefore, for a better understanding, the molecular pathogenesis of various oncogenic viruses like, hepatitis virus, human immunodeficiency viral (HIV), human papillomavirus (HPV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV), could be explored, especially, to expand many potent antivirals that may escalate the apoptosis of infected malignant cells while sparing normal and healthy ones. Moreover, contemporary therapies, such as engineered antibodies antiviral agents targeting signaling pathways and cell biomarkers, could inhibit viral oncogenesis. This review elaborates the recent advancements in both natural and synthetic antivirals to control viral oncogenesis. The study also highlights the challenges and future perspectives of using antivirals in viral oncogenesis.

Anoikis resistance--protagonists of breast cancer cells survive and metastasize after ECM detachment

Breast cancer exhibits the highest global incidence among all tumor types. Regardless of the type of breast cancer, metastasis is a crucial cause of poor prognosis. Anoikis, a form of apoptosis initiated by cell detachment from the native environment, is an outside-in process commencing with the disruption of cytosolic connectors such as integrin-ECM and cadherin-cell. This disruption subsequently leads to intracellular cytoskeletal and signaling pathway alterations, ultimately activating caspases and initiating programmed cell death. Development of an anoikis-resistant phenotype is a critical initial step in tumor metastasis. Breast cancer employs a series of stromal alterations to suppress anoikis in cancer cells. Comprehensive investigation of anoikis resistance mechanisms can inform strategies for preventing and regressing metastatic breast cancer. The present review first outlines the physiological mechanisms of anoikis, elucidating the alterations in signaling pathways, cytoskeleton, and protein targets that transpire from the outside in upon adhesion loss in normal breast cells. The specific anoikis resistance mechanisms induced by pathological changes in various spatial structures during breast cancer development are also discussed. Additionally, the genetic loci of targets altered in the development of anoikis resistance in breast cancer, are summarized. Finally, the micro-RNAs and targeted drugs reported in the literature concerning anoikis are compiled, with keratocin being the most functionally comprehensive. Video Abstract.

Effect of aging on the formation and growth of colonic epithelial organoids by changes in cell cycle arrest through TGF-β-Smad3 signaling

BACKGROUND

This study aimed to investigate how aging alters the homeostasis of the colonic intestinal epithelium and regeneration after tissue injury using organoid models and to identify its underlying molecular mechanism.

METHODS

To investigate aging-related changes in the colonic intestinal epithelium, we conducted organoid cultures from old (older than 80 weeks) and young (6-10 weeks) mice and compared the number and size of organoids at day 5 of passage 0 and the growth rate of organoids between the two groups.

RESULTS

The number and size of organoids from old mice was significantly lower than that from young mice (p < 0.0001) at day 5 of passage 0. The growth rate of old-mouse organoids from day 4 to 5 of passage 0 was significantly slower than that of young-mouse organoids (2.21 times vs. 1.16 times, p < 0.001). RNA sequencing showed that TGF-β- and cell cycle-associated genes were associated with the aging effect. With regard to mRNA and protein levels, Smad3 and p-Smad3 in the old-mouse organoids were markedly increased compared with those in the young-mouse organoids. Decreased expression of ID1, increased expression of p16^INK4a, and increased cell cycle arrest were observed in the old mouse-organoids. Treatment with SB431542, a type I TGF-β receptor inhibitor, significantly increased the formation and growth of old-mouse organoids, and TGF-β1 treatment markedly suppressed the formation of young-mouse organoids. In the acute dextran sulfate sodium-colitis model and its organoid experiments, the colonic epithelial regeneration after tissue injury in old mice was significantly decreased compared with young mice.

CONCLUSIONS

Aging reduced the formation ability and growth rate of colonic epithelial organoids by increasing cell cycle arrest through TGF-β-Smad3-p16^INK4a signaling.

High glucose promotes the progression of colorectal cancer by activating the BMP4 signaling and inhibited by glucagon-like peptide-1 receptor agonist

BACKGROUND

The detailed molecular mechanism between type 2 diabetes mellitus (T2DM) and colorectal cancer (CRC) is still uncertain. Bone morphogenetic protein 4 (BMP4) dysregulation is implicated in T2DM and CRC, respectively. This study aims to investigate whether BMP4 can mediate the interaction of CRC with T2DM.

METHODS

We firstly explored the expression of BMP4 in The Cancer Genome Altas (TCGA) databases and CRC patients with or without DM from the Shanghai Tenth People's Hospital. The diabetic model of CRC cell lines in vitro and the mice model in vivo were developed to explore the BMP4 expression during CRC with or without diabetes. Further inhibition of BMP4 to observe its effects on CRC. Also, glucagon-like peptide-1 receptor agonist (GLP-1RA) was used to verify the underlying mechanism of hypoglycemic drugs on CRC via BMP4.

RESULTS

BMP4 expression was upregulated in CRC patients, and significantly higher in CRC patients with diabetes (P < 0.05). High glucose-induced insulin resistance (IR)-CRC cells and diabetic mice with metastasis model of CRC had increased BMP4 expression, activated BMP4-Smad1/5/8 pathway, and improved proliferative and metastatic ability mediated by epithelial-mesenchymal transition (EMT). And, treated CRC cells with exogenously BMP inhibitor-Noggin or transfected with lentivirus (sh-BMP4) could block the upregulated metastatic ability of CRC cells induced by IR. Meanwhile, GLP-1R was downregulated by high glucose-induced IR while unregulated by BMP4 inhibitor noggin, and treated GLP-1RA could suppress the proliferation of CRC cells induced by IR through downregulated BMP4.

CONCLUSIONS

BMP4 increased by high glucose promoted the EMT of CRC. The mechanism of the BMP4/Smad pathway was related to the susceptible metastasis of high glucose-induced IR-CRC. The commonly used hypoglycemic drug, GLP-1RA, inhibited the growth and promoted the apoptosis of CRC through the downregulation of BMP4. The result of our study suggested that BMP4 might serve as a therapeutic target in CRC patients with diabetes.

Induction of Reactive Bone Stromal Fibroblasts in 3D Models of Prostate Cancer Bone Metastases

A dynamic interplay between prostate cancer (PCa) cells and reactive bone stroma modulates the growth of metastases within the bone microenvironment. Of the stromal cells, metastasis-associated fibroblasts (MAFs) are known to contribute but are the least studied cell type in PCa tumour progression. It is the aim of the current study to establish a biologically relevant 3D in vitro model that mimics the cellular and molecular profiles of MAFs found in vivo. Using 3D in vitro cell culture models, the bone-derived fibroblast cell line, HS-5, was treated with conditioned media from metastatic-derived PCa cell lines, PC3 and MDA-PCa 2b, or mouse-derived fibroblasts 3T3. Two corresponding reactive cell lines were propagated: HS5-PC3 and HS5-MDA, and evaluated for alterations in morphology, phenotype, cellular behaviour, plus protein and genomic profiles. HS5-PC3 and HS5-MDA displayed distinct alterations in expression levels of N-Cadherin, non-functional E-Cadherin, alpha-smooth muscle actin (α-SMA), Tenascin C, and vimentin, along with transforming growth factor receptor expression (TGF β R1 and R2), consistent with subpopulations of MAFs reported in vivo. Transcriptomic analysis revealed a reversion of HS5-PC3 towards a metastatic phenotype with an upregulation in pathways known to regulate cancer invasion, proliferation, and angiogenesis. The exploitation of these engineered 3D models could help further unravel the novel biology regulating metastatic growth and the role fibroblasts play in the colonisation process.

Aloe-emodin ameliorated MI-induced cardiac remodeling in mice via inhibiting TGF-β/SMAD signaling via up-regulating SMAD7

BACKGROUND

Aloe-emodin (AE), a natural anthraquinone extract from traditional Chinese medicinal plants, has been certified to protect against acute myocardial ischemia. However, its effect on cardiac remodeling after chronic myocardial infarction (MI) and the possible mechanism remain unclear.

PURPOSE

This study investigated the effect of AE on cardiac remodeling and oxidative damage induced by myocardial infarction (MI) in vitro and explored the underlying mechanisms.

METHODS

Echocardiography and Masson staining were used to demonstrate myocardial dysfunction and fibrosis. Cell apoptosis was detected by TUNEL staining. The expressions of fibrosis-related factors such as type I collagen, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) were detected by Western blot.

RESULTS

Our data demonstrated that AE treatment significantly improved cardiac function, reduced structural remodeling, and reduced cardiac apoptosis and oxidative stress in mice with myocardial infarction. In vitro, AE could protect neonatal mouse cardiomyocytes (NMCM) from angiotensin II (Ang II)-induced cardiomyocyte hypertrophy and apoptosis, and significantly inhibited (p < 0.05) Ang II-induced reactive oxygen species (ROS) increase. Furthermore, AE treatment significantly reversed the Ang ii-induced upregulation.

CONCLUSION

In summary, our work reveals for the first time that AE activates the TGF-β signaling pathway by up-regulating Smad7 expression, which in turn regulates the expression of fibrosis-related genes, ultimately improving cardiac function, inhibiting the development of cardiac fibrosis and hypertrophy in rats with chronic MI.

Genome-wide CRISPR Screen Reveals RAB10 as a Synthetic Lethal Gene in Colorectal and Pancreatic Cancers Carrying SMAD4 Loss

The TGFβ signaling mediator SMAD4 is frequently mutated or deleted in colorectal and pancreatic cancers. SMAD4 acts as a tumor suppressor and its loss is associated with poorer patient outcomes. The purpose of this study was to find synthetic lethal interactions with SMAD4 deficiency to find novel therapeutic strategies for the treatment of patients with SMAD4-deficient colorectal or pancreatic cancers. Using pooled lentiviral single-guide RNA libraries, we conducted genome-wide loss-of-function screens in Cas9-expressing colorectal and pancreatic cancer cells harboring altered or wild-type SMAD4. The small GTPase protein RAB10 was identified and validated as a susceptibility gene in SMAD4-altered colorectal and pancreatic cancer cells. Rescue assays showed that RAB10 reintroduction reversed the antiproliferative effects of RAB10 knockout in SMAD4-negative cell lines. Further investigation is necessary to shed light on the mechanism by which RAB10 inhibition decreases cell proliferation of SMAD4-negative cells.

Significance

This study identified and validated RAB10 as new synthetic lethal gene with SMAD4. This was achieved by conducting a whole-genome CRISPR screens in different colorectal and pancreatic cell lines. A future RAB10 inhibitors could correspond to a new therapeutic solution for patients with cancer with SMAD4 deletion.

The mechanism and therapy of aortic aneurysms

Aortic aneurysm is a chronic aortic disease affected by many factors. Although it is generally asymptomatic, it poses a significant threat to human life due to a high risk of rupture. Because of its strong concealment, it is difficult to diagnose the disease in the early stage. At present, there are no effective drugs for the treatment of aneurysms. Surgical intervention and endovascular treatment are the only therapies. Although current studies have discovered that inflammatory responses as well as the production and activation of various proteases promote aortic aneurysm, the specific mechanisms remain unclear. Researchers are further exploring the pathogenesis of aneurysms to find new targets for diagnosis and treatment. To better understand aortic aneurysm, this review elaborates on the discovery history of aortic aneurysm, main classification and clinical manifestations, related molecular mechanisms, clinical cohort studies and animal models, with the ultimate goal of providing insights into the treatment of this devastating disease. The underlying problem with aneurysm disease is weakening of the aortic wall, leading to progressive dilation. If not treated in time, the aortic aneurysm eventually ruptures. An aortic aneurysm is a local enlargement of an artery caused by a weakening of the aortic wall. The disease is usually asymptomatic but leads to high mortality due to the risk of artery rupture.

Altered microRNA expression profile is linked to T-cell exhaustion-related pathways in pediatric patients with acute lymphoblastic leukemia

BACKGROUND

Although the phenotype and functions of exhausted T cells in several cancers have been identified, the involved molecular mechanisms remain to be further elucidated. In this regard, we have recently reported that the immunoregulatory cells, including myeloid-derived suppressor cells (MDSCs) and regulatory T cells (T_regs), share common dysregulated miRNAs that target specific immunosuppressive pathways in patients with in acute lymphoblastic leukemia (ALL).

AIM

In this study, we aimed to further explore whether similar dysregulation in miRNA expression is linked to T cell exhaustion and dysfunctionality in B cell ALL patients.

METHODS

Peripheral blood samples from pediatric patients with ALL were recruited before and after induction chemotherapy as well as from healthy donors. Affymetrix microarray platform was used for miRNA profiling, and qRT-PCR was used to validate the expression of certain miRNAs that are related to T cell exhaustion. Bioinformatics analysis was performed to explore whether the dysregulated miRNAs were linked to T-cell exhaustion related pathways.

RESULTS

A total of 516 miRNAs were dysregulated in ALL patients as compared to the healthy donor. Furthermore, among the total analyzed miRNAs, 10 were found to be linked to the key genes implicated in three exhaustion-related pathways; TGF-β, FOXO, and MAPK, as revealed by miR-pathway analysis. Moreover, qRT-PCR analysis showed similar expression pattern to those obtained by microarray analysis.

CONCLUSION

Our pilot study suggests the implication of certain miRNAs in T cell exhaustion pathways via targeting the specific key genes in those pathways.

Ly-6A-Induced Growth Inhibition and Cell Death in a Transformed CD4+ T Cell Line: Role of Tumor Necrosis Factor-α

Ly-6A, a member of the Ly-6/uPAR supergene family of proteins, is a cell adhesion and cell signaling protein. Signaling through Ly-6A activates the cell-intrinsic apoptotic cell death pathway in CD4⁺ T cell lines, as indicated by the release of cytochrome C, and activation of caspases 9 and 3. In addition, Ly-6A induces cytokine production and growth inhibition. The mechanism underlying the distinct cellular responses that are triggered by engaging Ly-6A protein has remained unknown. To examine the relatedness of these distinct responses, we have quantified the production of pro-apoptotic, growth inhibitory and tumor suppressive cytokines, such as TNF-α, TGF-β and a related protein GDF-10, in response to Ly-6A signaling. Anti-Ly-6A monoclonal antibody-induced activation of YH16.33 CD4⁺ T cell line generated low levels of TGF-β and GDF-10 but elevated levels of TNF-α. Blocking the biological activity of TNF-α resulted in reduced Ly-6A-induced apoptosis in T cells. The Ly-6A-induced response in the T cell line was distinct, as signaling through the antigen receptor complex did not cause growth inhibition and apoptosis despite high levels of TGF-β and GDF-10 that were detected in these cultures. Additionally, in response to antigen receptor complex signaling, lower amount of TNF-α was detected. These results indicate the contribution of TNF-α in the observed Ly-6A-induced growth inhibition and apoptosis and provide a mechanistic explanation for the biologically distinct responses observed in CD4⁺ T cells after engaging Ly-6A protein. Additionally, the findings reported here will aid in the understanding of inhibitory signaling initiated by Ly-6A protein, especially in the context of its potential immune checkpoint inhibitory role in T cells.