Abnormal lung development and cleft palate in mice lacking TGF-beta 3 indicates defects of epithelial-mesenchymal interaction

A Phase 1a Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of RO7303509, an Anti-TGFβ3 Antibody, in Healthy Volunteers

INTRODUCTION

Transforming growth factor beta (TGFβ) cytokines (TGFβ1, TGFβ2, and TGFβ3) play critical roles in tissue fibrosis. However, treatment with systemic pan-TGFβ inhibitors have demonstrated unacceptable toxicities. In this study, we evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of RO7303509, a high-affinity, TGFβ3-specific, humanized immunoglobulin G1 monoclonal antibody, in healthy adult volunteers (HVs).

METHODS

This phase 1a, randomized, double-blind trial included six cohorts for evaluation, with each cohort receiving single doses of placebo or RO7303509, administered intravenously (IV; 50 mg, 150 mg, 240 mg) or subcutaneously (SC; 240 mg, 675 mg, 1200 mg). The frequency and severity of adverse events (AEs) and RO7303509 serum concentrations were monitored throughout the study. We also measured serum periostin and cartilage oligomeric matrix protein (COMP) by immunoassay and developed a population pharmacokinetics model to characterize RO7303509 serum concentrations.

RESULTS

The study enrolled 49 HVs, with a median age of 39 (range 18-73) years. Ten (27.8%) RO7303509-treated subjects reported 24 AEs, and six (30.8%) placebo-treated subjects reported six AEs. The most frequent AEs related to the study drug were injection site reactions and infusion-related reactions. Maximum serum concentrations (Cmax) and area under the concentration-time curve from time 0 to infinity (AUC0-inf) values for RO7303509 appeared to increase dose-proportionally across all doses tested. Serum concentrations across cohorts were best characterized by a two-compartment model plus a depot compartment with first-order SC absorption kinetics. No subjects tested positive for anti-drug antibodies (ADAs) at baseline; one subject (2.8%; 50 mg IV) tested positive for ADAs at a single time point (day 15). No clear pharmacodynamic effects were observed for periostin or COMP upon TGFβ3 inhibition.

CONCLUSION

RO7303509 was well tolerated at single SC doses up to 1200 mg in HVs with favorable pharmacokinetic data that appeared to increase dose-proportionally. TGFβ3-specific inhibition may be suitable for development as a chronic antifibrotic therapy.

TRIAL REGISTRATION

ISRCTN13175485.

Epigenetic determinants and non-myocardial signaling pathways contributing to heart growth and regeneration

Congenital heart disease is the most common birth defect worldwide. Defective cardiac myogenesis is either a major presentation or associated with many types of congenital heart disease. Non-myocardial tissues, including endocardium and epicardium, function as a supporting hub for myocardial growth and maturation during heart development. Recent research findings suggest an emerging role of epigenetics in nonmyocytes supporting myocardial development. Understanding how growth signaling pathways in non-myocardial tissues are regulated by epigenetic factors will likely identify new disease mechanisms for congenital heart diseases and shed lights for novel therapeutic strategies for heart regeneration.

Cell type-specific transforming growth factor-β (TGF-β) signaling in the regulation of salivary gland fibrosis and regeneration

Salivary gland damage and hypofunction result from various disorders, including autoimmune Sjögren's disease (SjD) and IgG4-related disease (IgG4-RD), as well as a side effect of radiotherapy for treating head and neck cancers. There are no therapeutic strategies to prevent the loss of salivary gland function in these disorders nor facilitate functional salivary gland regeneration. However, ongoing aquaporin-1 gene therapy trials to restore saliva flow show promise. To identify and develop novel therapeutic targets, we must better understand the cell-specific signaling processes involved in salivary gland regeneration. Transforming growth factor-β (TGF-β) signaling is essential to tissue fibrosis, a major endpoint in salivary gland degeneration, which develops in the salivary glands of patients with SjD, IgG4-RD, and radiation-induced damage. Though the deposition and remodeling of extracellular matrix proteins are essential to repair salivary gland damage, pathological fibrosis results in tissue hardening and chronic salivary gland dysfunction orchestrated by multiple cell types, including fibroblasts, myofibroblasts, endothelial cells, stromal cells, and lymphocytes, macrophages, and other immune cell populations. This review is focused on the role of TGF-β signaling in the development of salivary gland fibrosis and the potential for targeting TGF-β as a novel therapeutic approach to regenerate functional salivary glands. The studies presented highlight the divergent roles of TGF-β signaling in salivary gland development and dysfunction and illuminate specific cell populations in damaged or diseased salivary glands that mediate the effects of TGF-β. Overall, these studies strongly support the premise that blocking TGF-β signaling holds promise for the regeneration of functional salivary glands.

Loss of LPAR6 and CAB39L dysregulates the basal-to-luminal urothelial differentiation program, contributing to bladder carcinogenesis

We describe a strategy that combines histologic and molecular mapping that permits interrogation of the chronology of changes associated with cancer development on a whole-organ scale. Using this approach, we present the sequence of alterations around RB1 in the development of bladder cancer. We show that RB1 is not involved in initial expansion of the preneoplastic clone. Instead, we found a set of contiguous genes that we term "forerunner" genes whose silencing is associated with the development of plaque-like field effects initiating carcinogenesis. Specifically, we identified five candidate forerunner genes (ITM2B, LPAR6, MLNR, CAB39L, and ARL11) mapping near RB1. Two of these genes, LPAR6 and CAB39L, are preferentially downregulated in the luminal and basal subtypes of bladder cancer, respectively. Their loss of function dysregulates urothelial differentiation, sensitizing the urothelium to N-butyl-N-(4-hydroxybutyl)nitrosamine-induced cancers, which recapitulate the luminal and basal subtypes of human bladder cancer.

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.

Advances in co-pathogenesis of the united airway diseases

According to the concept of "united airway diseases", the airway is a single organ in which upper and lower airway diseases are commonly comorbid. A range of inflammatory factors have been found to play an important role in the chain reaction of upper and lower airway diseases. However, the amount of research on this concept remains limited. The underlying mechanism of the relationship between typical diseases of the united airway, such as asthma, allergic rhinitis, and chronic sinusitis, also needs to be further explored. This review highlights the interaction between upper and lower respiratory diseases gathered from epidemiological, histoembryology, neural mechanistic, microbiological, and clinical studies, revealing the relationship between the upper and lower respiratory tracts.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Transforming growth factor beta signaling and craniofacial development: modeling human diseases in zebrafish

Humans and other jawed vertebrates rely heavily on their craniofacial skeleton for eating, breathing, and communicating. As such, it is vital that the elements of the craniofacial skeleton develop properly during embryogenesis to ensure a high quality of life and evolutionary fitness. Indeed, craniofacial abnormalities, including cleft palate and craniosynostosis, represent some of the most common congenital abnormalities in newborns. Like many other organ systems, the development of the craniofacial skeleton is complex, relying on specification and migration of the neural crest, patterning of the pharyngeal arches, and morphogenesis of each skeletal element into its final form. These processes must be carefully coordinated and integrated. One way this is achieved is through the spatial and temporal deployment of cell signaling pathways. Recent studies conducted using the zebrafish model underscore the importance of the Transforming Growth Factor Beta (TGF-β) and Bone Morphogenetic Protein (BMP) pathways in craniofacial development. Although both pathways contain similar components, each pathway results in unique outcomes on a cellular level. In this review, we will cover studies conducted using zebrafish that show the necessity of these pathways in each stage of craniofacial development, starting with the induction of the neural crest, and ending with the morphogenesis of craniofacial elements. We will also cover human skeletal and craniofacial diseases and malformations caused by mutations in the components of these pathways (e.g., cleft palate, craniosynostosis, etc.) and the potential utility of zebrafish in studying the etiology of these diseases. We will also briefly cover the utility of the zebrafish model in joint development and biology and discuss the role of TGF-β/BMP signaling in these processes and the diseases that result from aberrancies in these pathways, including osteoarthritis and multiple synostoses syndrome. Overall, this review will demonstrate the critical roles of TGF-β/BMP signaling in craniofacial development and show the utility of the zebrafish model in development and disease.

The roles and regulatory mechanisms of TGF-β and BMP signaling in bone and cartilage development, homeostasis and disease

Transforming growth factor-βs (TGF-βs) and bone morphometric proteins (BMPs) belong to the TGF-β superfamily and perform essential functions during osteoblast and chondrocyte lineage commitment and differentiation, skeletal development, and homeostasis. TGF-βs and BMPs transduce signals through SMAD-dependent and -independent pathways; specifically, they recruit different receptor heterotetramers and R-Smad complexes, resulting in unique biological readouts. BMPs promote osteogenesis, osteoclastogenesis, and chondrogenesis at all differentiation stages, while TGF-βs play different roles in a stage-dependent manner. BMPs and TGF-β have opposite functions in articular cartilage homeostasis. Moreover, TGF-β has a specific role in maintaining the osteocyte network. The precise activation of BMP and TGF-β signaling requires regulatory machinery at multiple levels, including latency control in the matrix, extracellular antagonists, ubiquitination and phosphorylation in the cytoplasm, nucleus-cytoplasm transportation, and transcriptional co-regulation in the nuclei. This review weaves the background information with the latest advances in the signaling facilitated by TGF-βs and BMPs, and the advanced understanding of their diverse physiological functions and regulations. This review also summarizes the human diseases and mouse models associated with disordered TGF-β and BMP signaling. A more precise understanding of the BMP and TGF-β signaling could facilitate the development of bona fide clinical applications in treating bone and cartilage disorders.

TGF-β1 and TGF-β3, but not TGF-β2, are upregulated in the ovaries of ovarian hyperstimulation syndrome†

Ovarian hyperstimulation syndrome (OHSS) is a life-threatening and potentially fatal complication during in vitro fertilization treatment. The levels of transforming growth factor-β1 (TGF-β1) are upregulated in human follicular fluid and granulosa-lutein cells (hGL) of OHSS patients and could contribute to the development of OHSS by downregulating steroidogenic acute regulatory protein (StAR) expression. However, whether the same is true for the other two members of the TGF-β family, TGF-β2 and -β3, remains unknown. We showed that all three TGF-β isoforms were expressed in human follicular fluid. In comparison, TGF-β1 was expressed at the highest level, followed by TGF-β2 and TGF-β3. Compared to non-OHSS patients, follicular fluid levels of TGF-β1 and TGF-β3 were significantly upregulated in OHSS patients. The same results were observed in mRNA levels of TGF-β isoforms in hGL cells and ovaries of OHSS rats. In addition, StAR mRNA levels were upregulated in hGL cells of OHSS patients and the ovaries of OHSS rats. Treatment cells with TGF-β isoforms downregulated the StAR expression with a comparable effect. Moreover, activations of SMAD3 signaling were required for TGF-β isoforms-induced downregulation of StAR expression. This study indicates that follicular fluid TGF-β1 and TGF-β3 levels could be used as biomarkers and therapeutic targets for the OHSS.

TGM6, a helminth secretory product, mimics TGF-β binding to TβRII to antagonize TGF-β signaling in fibroblasts

The murine helminth parasite Heligmosomoides polygyrus expresses a family of proteins structurally related to TGF-β Mimic 1 (TGM1), a secreted five domain protein that activates the TGF-β pathway and converts naïve T lymphocytes to immunosuppressive Tregs. TGM1 signals through the TGF-β type I and type II receptors, TβRI and TβRII, with domains 1-2 and 3 binding TβRI and TβRII, respectively, and domains 4-5 binding CD44, a co-receptor abundant on T cells. TGM6 is a homologue of TGM1 that is co-expressed with TGM1, but lacks domains 1 and 2. Herein, we show that TGM6 binds TβRII through domain 3, but does not bind TβRI, or other type I or type II receptors of the TGF-β family. In TGF-β reporter assays in fibroblasts, TGM6, but not truncated TGM6 lacking domains 4 and 5, potently inhibits TGF-β- and TGM1-induced signaling, consistent with its ability to bind TβRII but not TβRI or other receptors of the TGF-β family. However, TGM6 does not bind CD44 and is unable to inhibit TGF-β and TGM1 signaling in T cells. To understand how TGM6 binds TβRII, the X-ray crystal structure of the TGM6 domain 3 bound to TβRII was determined at 1.4 Å. This showed that TGM6 domain 3 binds TβRII through an interface remarkably similar to the TGF-β:TβRII interface. These results suggest that TGM6 has adapted its domain structure and sequence to mimic TGF-β binding to TβRII and function as a potent TGF-β and TGM1 antagonist in fibroblasts. The coexpression of TGM6, along with the immunosuppressive TGMs that activate the TGF-β pathway, may prevent tissue damage caused by the parasite as it progresses through its life cycle from the intestinal lumen to submucosal tissues and back again.

Targeting transforming growth factor beta signaling in metastatic osteosarcoma

Osteosarcoma is a rare type of bone cancer, and half of the cases affect children and adolescents younger than 20 years of age. Despite intensive efforts to improve both chemotherapeutics and surgical management, the clinical outcome for metastatic osteosarcoma remains poor. Transforming growth factor β (TGF-β) is one of the most abundant growth factors in bones. The TGF-β signaling pathway has complex and contradictory roles in the pathogenesis of human cancers. TGF-β is primarily a tumor suppressor that inhibits proliferation and induces apoptosis of premalignant epithelial cells. In the later stages of cancer progression, however, TGF-β functions as a metastasis promoter by promoting tumor growth, inducing epithelial-mesenchymal transition (EMT), blocking antitumor immune responses, increasing tumor-associated fibrosis, and enhancing angiogenesis. In contrast with the dual effects of TGF-β on carcinoma (epithelial origin) progression, TGF-β seems to mainly have a pro-tumoral effect on sarcomas including osteosarcoma (mesenchymal origin). Many drugs that target TGF-β signaling have been developed: neutralizing antibodies that prevent TGF-β binding to receptor complexes; ligand trap employing recombinant Fc-fusion proteins containing the soluble ectodomain of either type II (TβRII) or the type III receptor ((TβRIII), preventing TGF-β from binding to its receptors; antisense nucleotides that reduce TGF-β expression at the transcriptional/translational level; small molecule inhibitors of serine/threonine kinases of the type I receptor (TβRI) preventing downstream signaling; and vaccines that contain cell lines transfected with TβRII antisense genes, or target furin convertase, resulting in reduced TGF-β signaling. TGF-β antagonists have been shown to have effects on osteosarcoma in vitro and in vivo. One of the small molecule TβRI inhibitors, Vactosertib, is currently undergoing a phase 1/2 clinical trial to evaluate its effect on osteosarcoma. Several phase 1/2/3 clinical trials have shown TGF-β antagonists are safe and well tolerated. For instance, Luspatercept, a TGF-β ligand trap, has been approved by the FDA for the treatment of anemia associated with myeloid dysplastic syndrome (MDS) with ring sideroblasts/mutated SF3B1 with acceptable safety. Clinical trials evaluating the long-term safety of Luspatercept are in process.

The Research Progress in Transforming Growth Factor-β2

Transforming growth factor-beta 2 (TGF-β2), an important member of the TGF-β family, is a secreted protein that is involved in many biological processes, such as cell growth, proliferation, migration, and differentiation. TGF-β2 had been thought to be functionally identical to TGF-β1; however, an increasing number of recent studies uncovered the distinctive features of TGF-β2 in terms of its expression, activation, and biological functions. Mice deficient in TGF-β2 showed remarkable developmental abnormalities in multiple organs, especially the cardiovascular system. Dysregulation of TGF-β2 signalling was associated with tumorigenesis, eye diseases, cardiovascular diseases, immune disorders, as well as motor system diseases. Here, we provide a comprehensive review of the research progress in TGF-β2 to support further research on TGF-β2.

The Role of TGF-β during Pregnancy and Pregnancy Complications

Transforming growth factor beta (TGF-β), a multifunctional cytokine, is one of the most important inflammatory cytokines closely related to pregnancy. It plays significant roles in hormone secretion, placental development, and embryonic growth during pregnancy. TGF-β is implicated in embryo implantation and inhibits the invasion of extraepithelial trophoblast cells. It also moderates the mother-fetus interaction by adjusting the secretion pattern of immunomodulatory factors in the placenta, consequently influencing the mother's immune cells. The TGF-β family regulates the development of the nervous, respiratory, and cardiovascular systems by regulating gene expression. Furthermore, TGF-β has been associated with various pregnancy complications. An increase in TGF-β levels can induce the occurrences of pre-eclampsia and gestational diabetes mellitus, while a decrease can lead to recurrent miscarriage due to the interference of the immune tolerance environment. This review focuses on the role of TGF-β in embryo implantation and development, providing new insights for the clinical prevention and treatment of pregnancy complications.

Cleft palate and minor metabolic disturbances in a mouse global Arl15 gene knockout

ARL15, a small GTPase protein, was linked to metabolic traits in association studies. We aimed to test the Arl15 gene as a functional candidate for metabolic traits in the mouse. CRISPR/Cas9 germline knockout (KO) of Arl15 showed that homozygotes were postnatal lethal and exhibited a complete cleft palate (CP). Also, decreased cell migration was observed from Arl15 KO mouse embryonic fibroblasts (MEFs). Metabolic phenotyping of heterozygotes showed that females had reduced fat mass on a chow diet from 14 weeks of age. Mild body composition phenotypes were also observed in heterozygous mice on a high-fat diet (HFD)/low-fat diet (LFD). Females on a HFD showed reduced body weight, gonadal fat depot weight and brown adipose tissue (BAT) weight. In contrast, in the LFD group, females showed increased bone mineral density (BMD), while males showed a trend toward reduced BMD. Clinical biochemistry analysis of plasma on HFD showed transient lower adiponectin at 20 weeks of age in females. Urinary and plasma Mg2+ concentrations were not significantly different. Our phenotyping data showed that Arl15 is essential for craniofacial development. Adult metabolic phenotyping revealed potential roles in brown adipose tissue and bone development.

Effects of TP63 mutations on keratinocyte adhesion and migration

The goal of this study was to investigate the molecular mechanisms responsible for the formation of skin erosions in patients affected by Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC). This ectodermal dysplasia is caused by mutations in the TP63 gene, which encodes several transcription factors that control epidermal development and homeostasis. We generated induced pluripotent stem cells (iPSC) from AEC patients and corrected the TP63 mutations using genome editing tools. Three pairs of the resulting conisogenic iPSC lines were differentiated into keratinocytes (iPSC-K). We identified a significant downregulation of key components of hemidesmosomes and focal adhesions in AEC iPSC-K compared to their gene-corrected counterparts. Further, we demonstrated reduced AEC iPSC-K migration, suggesting the possibility that a process critical for cutaneous wound healing might be impaired in AEC patients. Next, we generated chimeric mice expressing a TP63-AEC transgene and confirmed a downregulation of these genes in transgene-expressing cells in vivo. Finally, we also observed these abnormalities in AEC patient skin. Our findings suggest that integrin defects in AEC patients might weaken the adhesion of keratinocytes to the basement membrane. We propose that reduced expression of extracellular matrix adhesion receptors, potentially in conjunction with previously identified desmosomal protein defects, contribute to skin erosions in AEC.

Gene Regulatory Networks and Signaling Pathways in Palatogenesis and Cleft Palate: A Comprehensive Review

Palatogenesis is a complex and intricate process involving the formation of the palate through various morphogenetic events highly dependent on the surrounding context. These events comprise outgrowth of palatal shelves from embryonic maxillary prominences, their elevation from a vertical to a horizontal position above the tongue, and their subsequent adhesion and fusion at the midline to separate oral and nasal cavities. Disruptions in any of these processes can result in cleft palate, a common congenital abnormality that significantly affects patient's quality of life, despite surgical intervention. Although many genes involved in palatogenesis have been identified through studies on genetically modified mice and human genetics, the precise roles of these genes and their products in signaling networks that regulate palatogenesis remain elusive. Recent investigations have revealed that palatal shelf growth, patterning, adhesion, and fusion are intricately regulated by numerous transcription factors and signaling pathways, including Sonic hedgehog (Shh), bone morphogenetic protein (Bmp), fibroblast growth factor (Fgf), transforming growth factor beta (Tgf-β), Wnt signaling, and others. These studies have also identified a significant number of genes that are essential for palate development. Integrated information from these studies offers novel insights into gene regulatory networks and dynamic cellular processes underlying palatal shelf elevation, contact, and fusion, deepening our understanding of palatogenesis, and facilitating the development of more efficacious treatments for cleft palate.

The Role of SOX9 in IGF-II-Mediated Pulmonary Fibrosis

Pulmonary fibrosis (PF) associated with systemic sclerosis (SSc) results in significant morbidity and mortality. We previously reported that insulin-like growth factor-II (IGF-II) is overexpressed in lung tissues and fibroblasts from SSc patients, and IGF-II fosters fibrosis by upregulating collagen type I, fibronectin, and TGFβ. We now show that IGF-II augments mRNA levels of profibrotic signaling molecules TGFβ2 (p ≤ 0.01) and TGFβ3 (p ≤ 0.05), collagen type III (p ≤ 0.01), and the collagen posttranslational modification enzymes P4HA2 (p ≤ 0.05), P3H2 (p ≤ 0.05), LOX (p = 0.065), LOXL2 (p ≤ 0.05), LOXL4 (p ≤ 0.05) in primary human lung fibroblasts. IGF-II increases protein levels of TGFβ2 (p ≤ 0.01), as well as COL3A1, P4HA2, P4Hβ, and LOXL4 (p ≤ 0.05). In contrast, IGF-II decreases mRNA levels of the collagen degradation enzymes cathepsin (CTS) K, CTSB, and CTSL and protein levels of CTSK (p ≤ 0.05). The SRY-box transcription factor 9 (SOX9) is overexpressed in SSc lung tissues at the mRNA (p ≤ 0.05) and protein (p ≤ 0.01) levels compared to healthy controls. IGF-II induces SOX9 in lung fibroblasts (p ≤ 0.05) via the IGF1R/IR hybrid receptor, and SOX9 regulates TGFβ2 (p ≤ 0.05), TGFβ3 (p ≤ 0.05), COL3A1 (p ≤ 0.01), and P4HA2 (p ≤ 0.001) downstream of IGF-II. Our results identify a novel IGF-II signaling axis and downstream targets that are regulated in a SOX9-dependent and -independent manner. Our findings provide novel insights on the role of IGF-II in promoting pulmonary fibrosis.

Mechanism of ELL-associated factor 2 and vasohibin 1 regulating invasion, migration, and angiogenesis in colorectal cancer

BACKGROUND

As a novel endogenous anti-angiogenic molecule, vasohibin 1 (VASH1) is not only expressed in tumor stroma, but also in tumor tissue. Moreover, studies have shown that VASH1 may be a prognostic marker in colorectal cancer (CRC). Knockdown of VASH1 enhanced transforming growth factor-β1 (TGF-β1)/Smad3 pathway activity and type I/III collagen production. Our previous findings suggest that ELL-associated factor 2 (EAF2) may play a tumor suppressor and protective role in the development and progression of CRC by regulating signal transducer and activator of transcription 3 (STAT3)/TGF-β1 signaling pathway. However, the functional role and mechanism of VASH1-mediated TGF-β1 related pathway in CRC has not been elucidated.

AIM

To investigate the expression of VASH1 in CRC and its correlation with the expression of EAF2. Furthermore, we studied the functional role and mechanism of VASH1 involved in the regulation and protection of EAF2 in CRC cells in vitro.

METHODS

We collected colorectal adenocarcinoma and corresponding adjacent tissues to investigate the clinical expression of EAF2 protein and VASH1 protein in patients with advanced CRC. Following, we investigated the effect and mechanism of EAF2 and VASH1 on the invasion, migration and angiogenesis of CRC cells in vitro using plasmid transfection.

RESULTS

Our findings indicated that EAF2 was down-regulated and VASH1 was up-regulated in advanced CRC tissue compared to normal colorectal tissue. Kaplan-Meier survival analysis showed that the higher EAF2 Level group and the lower VASH1 Level group had a higher survival rate. Overexpression of EAF2 might inhibit the activity of STAT3/TGF-β1 pathway by up-regulating the expression of VASH1, and then weaken the invasion, migration and angiogenesis of CRC cells.

CONCLUSION

This study suggests that EAF2 and VASH1 may serve as new diagnostic and prognostic markers for CRC, and provide a clinical basis for exploring new biomarkers for CRC. This study complements the mechanism of EAF2 in CRC cells, enriches the role and mechanism of CRC cell-derived VASH1, and provides a new possible subtype of CRC as a therapeutic target of STAT3/TGF-β1 pathway.

Effects of TP63 Mutations on Keratinocyte Adhesion and Migration

The goal of this study was to investigate the molecular mechanisms responsible for the formation of skin erosions in patients affected by Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC). This ectodermal dysplasia is caused by mutations in the TP63 gene, which encodes several transcription factors that control epidermal development and homeostasis. We generated induced pluripotent stem cells (iPSC) from AEC patients and corrected the TP63 mutations using genome editing tools. Three pairs of the resulting conisogenic iPSC lines were differentiated into keratinocytes (iPSC-K). We identified a significant downregulation of key components of hemidesmosomes and focal adhesions in AEC iPSC-K compared to their gene-corrected counterparts. Further, we demonstrated reduced iPSC-K migration, suggesting the possibility that a process critical for cutaneous wound healing might be impaired in AEC patients. Next, we generated chimeric mice expressing a TP63-AEC transgene and confirmed a downregulation of these genes in transgene-expressing cells in vivo. Finally, we also observed these abnormalities in AEC patient skin. Our findings suggest that integrin defects in AEC patients might weaken the adhesion of keratinocytes to the basement membrane. We propose that reduced expression of extracellular matrix adhesion receptors, potentially in conjunction with previously identified desmosomal protein defects, contribute to skin erosions in AEC.

TGFβ signaling pathways in human health and disease

Transforming growth factor beta (TGFβ) is named for the function it was originally discovered to perform-transformation of normal cells into aggressively growing malignant cells. It became apparent after more than 30 years of research, however, that TGFβ is a multifaceted molecule with a myriad of different activities. TGFβs are widely expressed with almost every cell in the human body producing one or another TGFβ family member and expressing its receptors. Importantly, specific effects of this growth factor family differ in different cell types and under different physiologic and pathologic conditions. One of the more important and critical TGFβ activities is the regulation of cell fate, especially in the vasculature, that will be the focus of this review.

Canonical Wnt signaling is not required for Tgfb3 expression in the basal medial edge epithelium during palatogenesis

The secondary palate forms from two lateral primordia called the palatal shelves which form a contact in the midline, become adherent at the fusing interface (medial edge epithelia, MEE) and subsequently fuse. The gene encoding transforming growth factor-ß3 (Tgfb3) is strongly and specifically expressed in MEE cells. Our previous study suggested that Tgfb3 expression is controlled via upstream cis-regulatory elements in and around the neighboring Ift43 gene. Another study suggested that the canonical Wnt signaling via ß-Catenin is responsible for the MEE-specific Tgfb3 gene expression, since deletion of the Ctnnb1 gene by a commonly used Keratin 14-Cre (K14Cre) mouse line almost completely abolished Tgfb3 expression in the MEE resulting in cleft palate. Here, we wanted to analyze whether Tcf/Lef consensus binding sites located in the previously identified regions of the Ift43 gene are responsible for the spatiotemporal control of Tgfb3 expression during palatogenesis. We show that contrary to the previous report, deletion of the Ctnnb1 gene in basal MEE cells by the K14Cre driver (the same K14Cre mouse line was used as in the previous study referenced above) does not affect the MEE-specific Tgfb3 expression or TGFß3-dependent palatal epithelial fusion. All mutant embryos showed a lack of palatal rugae accompanied by other craniofacial defects, e.g., a narrow snout and a small upper lip, while only a small subset (<5%) of Ctnnb1 mutants displayed a cleft palate. Moreover, the K14Cre:Ctnnb1 embryos showed reduced levels and altered patterns of Shh expression. Our present data imply that epithelial ß-catenin may not be required for MEE-specific Tgfb3 expression or palatal epithelial fusion.

Di-n-butyl phthalate induces oversecretion of vascular endothelium-derived NAP-2 and promotes epithelial-mesenchymal transition of urothelial cells in newborn hypospadias rats

Di-n-butyl phthalate (DBP) is a plasticizer commonly used in industrial production and is present in our daily life. It has been confirmed that DBP causes genitourinary malformations, especially hypospadias. However, the research of hypospadias mainly focusses on the genital tubercle in previous studies. In this study, we found DBP could affect the exocrine function of the vascular endothelium which disturb the development of genital nodules and induced hypospadias. We used cytokine array to find that vascular endothelium-derived NAP-2 may be a major abnormal secreted cytokine with biological functions. The transcriptomic sequencing analysis showed that abnormal activation of the RhoA/ROCK signaling pathway was the main reason for increased NAP-2 secretion. The expression levels of epithelial-mesenchymal transition (EMT) biomarkers and NAP-2 in hypospadias animal models were detected with Immunohistochemistry, Western blot, Immunofluorescence, and ELISA methods. The expression levels of NAP-2, RhoA/ROCK signaling pathway related proteins, reactive oxygen species (ROS) levels in HUVEC cells, EMT biomarkers and migration capacity of urothelial cells cocultured with HUVEC were measured with ELISA, flow cytometry, Western blot or Transwell assay for further cell experiments. The results showed that DBP leaded to NAP-2 oversecretion from vascular endothelium mainly rely on the activation of RhoA/ROCK signaling pathway and ROS accumulation. The RhoA/ROCK inhibitor fasudil could partially decrease ROS production, and both fasudil and N-acetyl-L-cysteine (NAC) could decrease NAP-2 secretion. Meanwhile, the oversecretion of NAP-2 from HUVEC in coculture system promoted EMT and migration capacity of urothelial cells, and TGF-β inhibitor LY219761 could block the aberrant activation of EMT process. Therefore, it could be concluded that DBP increase NAP-2 secretion from vascular endothelium by RhoA/ROCK/ROS pathway, and further promote EMT in urothelial cells through TGF-β pathway. This study provided a novel direction for studying the occurrence of hypospadias and may provide a hypospadias predictive marker in the future.

Stretch regulates alveologenesis and homeostasis via mesenchymal Gαq/11-mediated TGFβ2 activation

Alveolar development and repair require tight spatiotemporal regulation of numerous signalling pathways that are influenced by chemical and mechanical stimuli. Mesenchymal cells play key roles in numerous developmental processes. Transforming growth factor-β (TGFβ) is essential for alveologenesis and lung repair, and the G protein α subunits Gαq and Gα11 (Gαq/11) transmit mechanical and chemical signals to activate TGFβ in epithelial cells. To understand the role of mesenchymal Gαq/11 in lung development, we generated constitutive (Pdgfrb-Cre+/-;Gnaqfl/fl;Gna11-/-) and inducible (Pdgfrb-Cre/ERT2+/-;Gnaqfl/fl;Gna11-/-) mesenchymal Gαq/11 deleted mice. Mice with constitutive Gαq/11 gene deletion exhibited abnormal alveolar development, with suppressed myofibroblast differentiation, altered mesenchymal cell synthetic function, and reduced lung TGFβ2 deposition, as well as kidney abnormalities. Tamoxifen-induced mesenchymal Gαq/11 gene deletion in adult mice resulted in emphysema associated with reduced TGFβ2 and elastin deposition. Cyclical mechanical stretch-induced TGFβ activation required Gαq/11 signalling and serine protease activity, but was independent of integrins, suggesting an isoform-specific role for TGFβ2 in this model. These data highlight a previously undescribed mechanism of cyclical stretch-induced Gαq/11-dependent TGFβ2 signalling in mesenchymal cells, which is imperative for normal alveologenesis and maintenance of lung homeostasis.

The Role of TGF-β3 in Radiation Response

Transforming growth factor-beta 3 (TGF-β3) is a ubiquitously expressed multifunctional cytokine involved in a range of physiological and pathological conditions, including embryogenesis, cell cycle regulation, immunoregulation, and fibrogenesis. The cytotoxic effects of ionizing radiation are employed in cancer radiotherapy, but its actions also influence cellular signaling pathways, including that of TGF-β3. Furthermore, the cell cycle regulating and anti-fibrotic effects of TGF-β3 have identified it as a potential mitigator of radiation- and chemotherapy-induced toxicity in healthy tissue. This review discusses the radiobiology of TGF-β3, its induction in tissue by ionizing radiation, and its potential radioprotective and anti-fibrotic effects.

Unlocking cardiomyocyte renewal potential for myocardial regeneration therapy

Cardiovascular disease remains the leading cause of mortality worldwide. Cardiomyocytes are irreversibly lost due to cardiac ischemia secondary to disease. This leads to increased cardiac fibrosis, poor contractility, cardiac hypertrophy, and subsequent life-threatening heart failure. Adult mammalian hearts exhibit notoriously low regenerative potential, further compounding the calamities described above. Neonatal mammalian hearts, on the other hand, display robust regenerative capacities. Lower vertebrates such as zebrafish and salamanders retain the ability to replenish lost cardiomyocytes throughout life. It is critical to understand the varying mechanisms that are responsible for these differences in cardiac regeneration across phylogeny and ontogeny. Adult mammalian cardiomyocyte cell cycle arrest and polyploidization have been proposed as major barriers to heart regeneration. Here we review current models about why adult mammalian cardiac regenerative potential is lost including changes in environmental oxygen levels, acquisition of endothermy, complex immune system development, and possible cancer risk tradeoffs. We also discuss recent progress and highlight conflicting reports pertaining to extrinsic and intrinsic signaling pathways that control cardiomyocyte proliferation and polyploidization in growth and regeneration. Uncovering the physiological brakes of cardiac regeneration could illuminate novel molecular targets and offer promising therapeutic strategies to treat heart failure.

Periderm Fate during Palatogenesis: TGF-β and Periderm Dedifferentiation

Failure of palatogenesis results in cleft palate, one of the most common congenital disabilities in humans. During the final phases of palatogenesis, the protective function of the peridermal cell layer must be eliminated for the medial edge epithelia to adhere properly, which is a prerequisite for the successful fusion of the secondary palate. However, a deeper understanding of the role and fate of the periderm in palatal adherence and fusion has been hampered due to a lack of appropriate periderm-specific genetic tools to examine this cell type in vivo. Here we used the cytokeratin-6A (Krt-6a) locus to develop both constitutive (Krt6ai-Cre) and inducible (Krt6ai-CreERT2) periderm-specific Cre driver mouse lines. These novel lines allowed us to achieve both the spatial and temporal control needed to dissect the periderm fate on a cellular resolution during palatogenesis. Our studies suggest that, already before the opposing palatal shelves contact each other, at least some palatal periderm cells start to gradually lose their squamous periderm-like phenotype and dedifferentiate into cuboidal cells, reminiscent of the basal epithelial cells seen in the palatal midline seam. Moreover, we show that transforming growth factor-β (TGF-β) signaling plays a critical periderm-specific role in palatogenesis. Thirty-three percent of embryos lacking a gene encoding the TGF-β type I receptor (Tgfbr1) in the periderm display a complete cleft of the secondary palate. Our subsequent experiments demonstrated that Tgfbr1-deficient periderm fails to undergo appropriate dedifferentiation. These studies define the periderm cell fate during palatogenesis and reveal a novel, critical role for TGF-β signaling in periderm dedifferentiation, which is a prerequisite for appropriate palatal epithelial adhesion and fusion.

Complex roles of TGF-β signaling pathways in lung development and bronchopulmonary dysplasia

As survival of extremely preterm infants continues to improve, there is also an associated increase in bronchopulmonary dysplasia (BPD), one of the most significant complications of preterm birth. BPD development is multifactorial resulting from exposure to multiple antenatal and postnatal stressors. BPD has both short-term health implications and long-term sequelae including increased respiratory, cardiovascular, and neurological morbidity. Transforming growth factor β (TGF-β) is an important signaling pathway in lung development, organ injury, and fibrosis and is implicated in the development of BPD. This review provides a detailed account on the role of TGF-β in antenatal and postnatal lung development, the effect of known risk factors for BPD on the TGF-β signaling pathway, and how medications currently in use or under development, for the prevention or treatment of BPD, affect TGF-β signaling.

Mechanism of action of non-coding RNAs and traditional Chinese medicine in myocardial fibrosis: Focus on the TGF-β/Smad signaling pathway

Cardiac fibrosis is a serious public health problem worldwide that is closely linked to progression of many cardiovascular diseases (CVDs) and adversely affects both the disease process and clinical prognosis. Numerous studies have shown that the TGF-β/Smad signaling pathway plays a key role in the progression of cardiac fibrosis. Therefore, targeted inhibition of the TGF-β/Smad signaling pathway may be a therapeutic measure for cardiac fibrosis. Currently, as the investigation on non-coding RNAs (ncRNAs) move forward, a variety of ncRNAs targeting TGF-β and its downstream Smad proteins have attracted high attention. Besides, Traditional Chinese Medicine (TCM) has been widely used in treating the cardiac fibrosis. As more and more molecular mechanisms of natural products, herbal formulas, and proprietary Chinese medicines are revealed, TCM has been proven to act on cardiac fibrosis by modulating multiple targets and signaling pathways, especially the TGF-β/Smad. Therefore, this work summarizes the roles of TGF-β/Smad classical and non-classical signaling pathways in the cardiac fibrosis, and discusses the recent research advances in ncRNAs targeting the TGF-β/Smad signaling pathway and TCM against cardiac fibrosis. It is hoped, in this way, to give new insights into the prevention and treatment of cardiac fibrosis.

IL-17A expression by both T cells and non-T cells contribute to HSV-IL-2-induced CNS demyelination

Previously we reported that a recombinant HSV-1 expressing murine IL-2 (HSV-IL-2) causes CNS demyelination in different strains of mice and in a T cell-dependent manner. Since TH17 cells have been implicated in CNS pathology, in the present study, we looked into the effects of IL-17A-/- and three of its receptors on HSV-IL-2-induced CNS demyelination. IL-17A-/- mice did not develop CNS demyelination, while IL-17RA-/-, IL-17RC-/-, IL-17RD-/- and IL-17RA-/-RC-/- mice developed CNS demyelination. Adoptive transfer of T cells from wild-type (WT) mice to IL-17A-/- mice or T cells from IL-17A-/- mice to Rag-/- mice induced CNS demyelination in infected mice. Adoptive T cell experiments suggest that both T cells and non-T cells expressing IL-17A contribute to HSV-IL-2-induced CNS demyelination with no difference in the severity of demyelination between the two groups of IL-17A producing cells. IL-6, IL-10, or TGFβ did not contribute to CNS demyelination in infected mice. Transcriptome analysis between IL-17A-/- brain and spinal cord of infected mice with and without T cell transfer from WT mice revealed that "neuron projection extension involved in neuron projection guidance" and "ensheathment of neurons" pathways were associated with CNS demyelination. Collectively, the results indicate the importance of IL-17A in CNS demyelination and the possible involvement of more than three of IL-17 receptors in CNS demyelination.

Miglustat, a glucosylceramide synthase inhibitor, mitigates liver fibrosis through TGF-β/Smad pathway suppression in hepatic stellate cells

Transforming growth factor (TGF)-β/Smad pathway is implicated in the pathogenesis of liver fibrosis, a condition characterized by excessive deposition of extracellular matrix (ECM) proteins such as collagen in response to chronic inflammation. It has been reported that ceramide regulates collagen production through TGF-β/Smad pathway activation. In this study, we examined whether miglustat, an inhibitor of glucosylceramide synthase, can suppress liver fibrosis by reducing TGF-β/Smad pathway activity. Human hepatic stellate cells (HHSteCs) were cultured with TGF-β and multiple miglustat concentrations to examine dose-dependent effects on the expression levels of ECM-related genes and Smad proteins. To evaluate the efficacy of miglustat for fibrosis mitigation, C57BL/6 mice were treated with carbon tetrachloride (CCl₄) for 4 weeks to induce liver fibrosis, followed by combined CCl₄ plus miglustat for a further 2 weeks. To examine if miglustat can also prevent fibrosis, mice were treated with CCl₄ for 2 weeks, followed by CCl₄ plus miglustat for 2 weeks. Miglustat dose-dependently downregulated expression of α-smooth muscle actin and ECM components in TGF-β-treated HHSteCs. Both phosphorylation and nuclear translocation of Smad2 and Smad3 were also suppressed by miglustat treatment. Sirius-Red staining and hydroxyproline assays of model mouse liver samples revealed that miglustat reduced fibrosis, an effect accompanied by decreased expression of ECM. Our findings suggest that miglustat can both prevent and reverse liver fibrosis by inhibiting TGF-β/Smad pathway.

Microvascular significance of TGF-β axis activation in COVID-19

As 2023 approaches, the COVID-19 pandemic has killed millions. While vaccines have been a crucial intervention, only a few effective medications exist for prevention and treatment of COVID-19 in breakthrough cases or in unvaccinated or immunocompromised patients. SARS-CoV-2 displays early and unusual features of micro-thrombosis and immune dysregulation that target endothelial beds of the lungs, skin, and other organs. Notably, anticoagulation improves outcomes in some COVID-19 patients. The protein transforming growth factor-beta (TGF-β1) has constitutive roles in maintaining a healthy microvasculature through its roles in regulating inflammation, clotting, and wound healing. However, after infection (including viral infection) TGF-β1 activation may augment coagulation, cause immune dysregulation, and direct a path toward tissue fibrosis. Dysregulation of TGF-β signaling in immune cells and its localization in areas of microvascular injury are now well-described in COVID-19, and such events may contribute to the acute respiratory distress syndrome and skin micro-thrombosis outcomes frequently seen in severe COVID-19. The high concentration of TGF-β in platelets and in other cells within microvascular thrombi, its ability to activate the clotting cascade and dysregulate immune pathways, and its pro-fibrotic properties all contribute to a unique milieu in the COVID-19 microvasculature. This unique environment allows for propagation of microvascular clotting and immune dysregulation. In this review we summarize the physiological functions of TGF-β and detail the evidence for its effects on the microvasculature in COVID-19. In addition, we explore the potential role of existing TGF-β inhibitors for the prevention and treatment of COVID-19 associated microvascular thrombosis and immune dysregulation.

Spatiotemporal Expression and Functional Analysis of miRNA-22 in the Developing Secondary Palate

OBJECTIVE

Normal development of the embryonic orofacial region requires precise spatiotemporal coordination between numerous genes. MicroRNAs represent small, single-stranded, non-coding molecules that regulate gene expression. This study examines the role of microRNA-22 (miR-22) in murine orofacial ontogeny.

METHODS

Spatiotemporal and differential expression of miR-22 (mmu-miR-22-3p) within the developing secondary palate was determined by in situ hybridization and quantitative real-time PCR, respectively. Bioinformatic approaches were used to predict potential mRNA targets of miR-22 and analyze their association with cellular functions indispensable for normal orofacial ontogeny. An in vitro palate organ culture system was used to assess the role of miR-22 in secondary palate development.

RESULTS

There was a progressive increase in miR-22 expression from GD12.5 to GD14.5 in palatal processes. On GD12.5 and GD13.5, miR-22 was expressed in the future oral, nasal, and medial edge epithelia. On GD14.5, miR-22 expression was observed in the residual midline epithelial seam (MES), the nasal epithelium and the mesenchyme, but not in the oral epithelium. Inhibition of miR-22 activity in palate organ cultures resulted in failure of MES removal. Bioinformatic analyses revealed potential mRNA targets of miR-22 that may play significant roles in regulating apoptosis, migration, and/or convergence/extrusion, developmental processes that modulate MES removal during palatogenesis.

CONCLUSIONS

Results from the current study suggest a key role for miR-22 in the removal of the MES during palatogenesis and that miR-22 may represent a potential contributor to the etiology of cleft palate.

Dysregulation of the immune response in TGF-β signalopathies

The transforming growth factor-β (TGF-β) family of cytokines exerts pleiotropic functions during embryonic development, tissue homeostasis and repair as well as within the immune system. Single gene defects in individual component of this signaling machinery cause defined Mendelian diseases associated with aberrant activation of TGF-β signaling, ultimately leading to impaired development, immune responses or both. Gene defects that affect members of the TGF-β cytokine family result in more restricted phenotypes, while those affecting downstream components of the signaling machinery induce broader defects. These rare disorders, also known as TGF-β signalopathies, provide the unique opportunity to improve our understanding of the role and the relevance of the TGF-β signaling in the human immune system. Here, we summarize this elaborate signaling pathway, review the diverse clinical presentations and immunological phenotypes observed in these patients and discuss the phenotypic overlap between humans and mice genetically deficient for individual components of the TGF-β signaling cascade.

TCDD induces cleft palate through exosomes derived from mesenchymal cells

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) is a ubiquitous environmental toxicant and a notable teratogenic agent for cleft palate (CP), a common congenital structural malformation that can result from abnormalities during palatal shelf connection and/or fusion. The development of the palate requires precise coordination between mesenchymal and epithelial cells. Exosomes are vesicles secreted by cells and participate in organ development by transferring various bioactive molecules between cells and regulating cell proliferation, migration, apoptosis, and epithelial-mesenchymal transition (EMT); these vesicles represent a new method of intercellular communication. To explore how TCDD could influence palatal cell behaviors and communication, we treated mesenchymal cells with TCDD, collected the exosomes secreted by the cells, assessed the 2 types of palatal cells, and then observed the effects of TCDD-induced exosomes. We found that the effects of TCDD-induced exosomes were equal to those of TCDD. Thus, TCDD might change the genetic materials of palatal cells and exosomes to cause dysregulated gene expression from parental cells, affect cellular information communicators, and induce abnormal cellular behaviors that could lead to CP.

TGF-β Signaling in Metastatic Colorectal Cancer (mCRC): From Underlying Mechanism to Potential Applications in Clinical Development

Colorectal cancer (CRC) is a serious public health issue, and it has the leading incidence and mortality among malignant tumors worldwide. CRC patients with metastasis in the liver, lung or other distant sites always have poor prognosis. Thus, there is an urgent need to discover the underlying mechanisms of metastatic colorectal cancer (mCRC) and to develop optimal therapy for mCRC. Transforming growth factor-β (TGF-β) signaling plays a significant role in various physiologic and pathologic processes, and aberrant TGF-β signal transduction contributes to mCRC progression. In this review, we summarize the alterations of the TGF-β signaling pathway in mCRC patients, the functional mechanisms of TGF-β signaling, its promotion of epithelial-mesenchymal transition, its facilitation of angiogenesis, its suppression of anti-tumor activity of immune cells in the microenvironment and its contribution to stemness of CRC cells. We also discuss the possible applications of TGF-β signaling in mCRC diagnosis, prognosis and targeted therapies in clinical trials. Hopefully, these research advances in TGF-β signaling in mCRC will improve the development of new strategies that can be combined with molecular targeted therapy, immunotherapy and traditional therapies to achieve better efficacy and benefit mCRC patients in the near future.

HPV-Induced MiR-21 Promotes Epithelial Mesenchymal Transformation and Tumor Progression in Cervical Cancer Cells through the TGFβ R2/hTERC Pathway

Cervical cancer (CC) is a common malignant tumor in women. It ranks first among the malignant tumors of woman reproductive organs and is one of the most important cancers in the world. Current studies suggest that human papillomavirus (HPV) infection, especially high-risk persistent infection, is the basic cause of cervical precancerous lesions and cervical cancer. MicroRNA-21 (miR-21) plays a role similar to oncogenes in the occurrence and growth of malignant tumors and can be developed as a potential target for treating malignant tumors. Recently, the study of the mechanism of malignant invasion and metastasis has made great progress. The current consensus is that the invasion and metastasis of malignant tumors is a complicated biological process with multistep and multigene control; the process of epithelial mesenchymal transition (EMT) may be the initial event of invasion and metastasis of epithelial malignant tumors. EMT means that epithelial cells obtain the characteristics of mesenchymal cells, which has main characteristics such as the loss of epithelial cell characteristics and the achievement of mesenchymal cell features, and then induce epithelial cells to acquire the ability of migration and invasion, and participate in many physiological and pathological processes of human body, including embryogenesis, organ differentiation, tissue inflammation, and wound healing. Research has proved that miR-21 is associated with the invasion and metastasis of cervical cancer, and its specific mechanism has not been completely clear; EMT exerts a significant effect on the invasion and metastasis of epithelial malignant tumors; we speculate whether miR-21 regulates the EMT process of cervical cancer cells. ELISA and RT-PCR studied HPV-induced cervical cancer cells, and it was found that HPV may induce miR-21 to pass through the TGF β R2/hTERC pathway which promotes epithelial stromal transformation and tumor progression of cervical cancer cells.

Specificity of TGF-β1 signal designated by LRRC33 and integrin αVβ8

Myeloid lineage cells present the latent form of transforming growth factor-β1 (L-TGF-β1) to the membrane using an anchor protein LRRC33. Integrin α_Vβ₈ activates extracellular L-TGF-β1 to trigger the downstream signaling functions. However, the mechanism designating the specificity of TGF-β1 presentation and activation remains incompletely understood. Here, we report cryo-EM structures of human L-TGF-β1/LRRC33 and integrin α_Vβ₈/L-TGF-β1 complexes. Combined with biochemical and cell-based analyses, we demonstrate that LRRC33 only presents L-TGF-β1 but not the -β2 or -β3 isoforms due to difference of key residues on the growth factor domains. Moreover, we reveal a 2:2 binding mode of integrin α_Vβ₈ and L-TGF-β1, which shows higher avidity and more efficient L-TGF-β1 activation than previously reported 1:2 binding mode. We also uncover that the disulfide-linked loop of the integrin subunit β₈ determines its exquisite affinity to L-TGF-β1. Together, our findings provide important insights into the specificity of TGF-β1 signaling achieved by LRRC33 and integrin α_Vβ₈.

Revisiting the embryogenesis of lip and palate development

Clefts of the lip and palate (CLP), the major causes of congenital facial malformation globally, result from failure of fusion of the facial processes during embryogenesis. With a prevalence of 1 in 500-2500 live births, CLP causes major morbidity throughout life as a result of problems with facial appearance, feeding, speaking, obstructive apnoea, hearing and social adjustment and requires complex, multi-disciplinary care at considerable cost to healthcare systems worldwide. Long-term outcomes for affected individuals include increased mortality compared with their unaffected siblings. The frequent occurrence and major healthcare burden imposed by CLP highlight the importance of dissecting the molecular mechanisms driving facial development. Identification of the genetic mutations underlying syndromic forms of CLP, where CLP occurs in association with non-cleft clinical features, allied to developmental studies using appropriate animal models is central to our understanding of the molecular events underlying development of the lip and palate and, ultimately, how these are disturbed in CLP.

Elevated TGFβ signaling contributes to ocular anterior segment dysgenesis in Col4a1 mutant mice

Ocular anterior segment dysgenesis (ASD) refers to a collection of developmental disorders affecting the anterior structures of the eye. Although a number of genes have been implicated in the etiology of ASD, the underlying pathogenetic mechanisms remain unclear. Mutations in genes encoding collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome, a multi-system disorder that often includes ocular manifestations such as ASD and glaucoma. COL4A1 and COL4A2 are abundant basement membrane proteins that provide structural support to tissues and modulate signaling through interactions with other extracellular matrix proteins, growth factors, and cell surface receptors. In this study, we used a combination of histological, molecular, genetic and pharmacological approaches to demonstrate that altered TGFβ signaling contributes to ASD in mouse models of Gould syndrome. We show that TGFβ signaling was elevated in anterior segments from Col4a1 mutant mice and that genetically reducing TGFβ signaling partially prevented ASD. Notably, we identified distinct roles for TGFβ1 and TGFβ2 in ocular defects observed in Col4a1 mutant mice. Importantly, we show that pharmacologically promoting type IV collagen secretion or reducing TGFβ signaling ameliorated ocular pathology in Col4a1 mutant mice. Overall, our findings demonstrate that altered TGFβ signaling contributes to COL4A1-related ocular dysgenesis and implicate this pathway as a potential therapeutic target for the treatment of Gould syndrome.

Convergent evolution of a parasite-encoded complement control protein-scaffold to mimic binding of mammalian TGF-β to its receptors, TβRI and TβRII

The mouse intestinal helminth Heligmosomoides polygyrus modulates host immune responses by secreting a transforming growth factor (TGF)-β mimic (TGM), to expand the population of Foxp3⁺ T_regs. TGM comprises five complement control protein (CCP)-like domains, designated D1-D5. Though lacking homology to TGF-β, TGM binds directly to the TGF-β receptors TβRI and TβRII and stimulates the differentiation of naïve T-cells into T_regs. However, the molecular determinants of binding are unclear. Here, we used surface plasmon resonance, isothermal calorimetry, NMR spectroscopy, and mutagenesis to investigate how TGM binds the TGF-β receptors. We demonstrate that binding is modular, with D1-D2 binding to TβRI and D3 binding to TβRII. D1-D2 and D3 were further shown to compete with TGF-β(TβRII)₂ and TGF-β for binding to TβRI and TβRII, respectively. The solution structure of TGM-D3 revealed that TGM adopts a CCP-like fold but is also modified to allow the C-terminal strand to diverge, leading to an expansion of the domain and opening potential interaction surfaces. TGM-D3 also incorporates a long structurally ordered hypervariable loop, adding further potential interaction sites. Through NMR shift perturbations and binding studies of TGM-D3 and TβRII variants, TGM-D3 was shown to occupy the same site of TβRII as bound by TGF-β using both a novel interaction surface and the hypervariable loop. These results, together with the identification of other secreted CCP-like proteins with immunomodulatory activity in H. polygyrus, suggest that TGM is part of a larger family of evolutionarily plastic parasite effector molecules that mediate novel interactions with their host.

Hedgehog-responsive PDGFRa(+) fibroblasts maintain a unique pool of alveolar epithelial progenitor cells during alveologenesis

The lung alveolus is lined with alveolar type 1 (AT1) and type 2 (AT2) epithelial cells. During alveologenesis, increasing demand associated with expanding alveolar numbers is met by proliferating progenitor AT2s (pAT2). Little information exists regarding the identity of this population and their niche microenvironment. We show that during alveologenesis, Hedgehog-responsive PDGFRa(+) progenitors (also known as SCMFs) are a source of secreted trophic molecules that maintain a unique pAT2 population. SCMFs are in turn maintained by TGFβ signaling. Compound inactivation of Alk5 TβR2 in SCMFs reduced their numbers and depleted the pAT2 pool without impacting differentiation of daughter cells. In lungs of preterm infants who died with bronchopulmonary dysplasia, PDGFRa is reduced and the number of proliferative AT2s is diminished, indicating that an evolutionarily conserved mechanism governs pAT2 behavior during alveologenesis. SCMFs are a transient cell population, active only during alveologenesis, making them a unique stage-specific niche mesodermal cell type in mammalian organs.

Research progress on drugs targeting the TGF-β signaling pathway in fibrotic diseases

Tissue fibrosis is a key factor leading to disability and death worldwide; however, thus far, there are no approved treatments for fibrosis. Transforming growth factor (TGF)-β is a major pro-fibrotic cytokine, which is expected to become a target in the treatment of fibrosis; however, since TGF-β has a wide range of biological functions involving a variety of biological processes in the body, a slight change in TGF-β may have a systematic effect. Indiscriminate inhibition of TGF-β can lead to adverse reactions, which can affect the efficacy of treatment. Therefore, it has become very important to explore how both the TGF-β signaling pathway is inhibited and the safe and efficient TGF-β small molecule inhibitors or neutralizing antibodies are designed in the treatment of fibrotic diseases. In this review, we mainly discuss the key role of the TGF-β signaling pathway in fibrotic diseases, as well as the development of fibrotic drugs in recent years, and explore potential targets in the treatment of fibrotic diseases in order to guide subsequent drug development.

Mouse models in palate development and orofacial cleft research: Understanding the crucial role and regulation of epithelial integrity in facial and palate morphogenesis

Cleft lip and cleft palate are common birth defects resulting from genetic and/or environmental perturbations of facial development in utero. Facial morphogenesis commences during early embryogenesis, with cranial neural crest cells interacting with the surface ectoderm to form initially partly separate facial primordia consisting of the medial and lateral nasal prominences, and paired maxillary and mandibular processes. As these facial primordia grow around the primitive oral cavity and merge toward the ventral midline, the surface ectoderm undergoes a critical differentiation step to form an outer layer of flattened and tightly connected periderm cells with a non-stick apical surface that prevents epithelial adhesion. Formation of the upper lip and palate requires spatiotemporally regulated inter-epithelial adhesions and subsequent dissolution of the intervening epithelial seam between the maxillary and medial/lateral nasal processes and between the palatal shelves. Proper regulation of epithelial integrity plays a paramount role during human facial development, as mutations in genes encoding epithelial adhesion molecules and their regulators have been associated with syndromic and non-syndromic orofacial clefts. In this chapter, we summarize mouse genetic studies that have been instrumental in unraveling the mechanisms regulating epithelial integrity and periderm differentiation during facial and palate development. Since proper epithelial integrity also plays crucial roles in wound healing and cancer, understanding the mechanisms regulating epithelial integrity during facial development have direct implications for improvement in clinical care of craniofacial patients.

Overcoming TGFβ-mediated immune evasion in cancer

Transforming growth factor-β (TGFβ) signalling controls multiple cell fate decisions during development and tissue homeostasis; hence, dysregulation of this pathway can drive several diseases, including cancer. Here we discuss the influence that TGFβ exerts on the composition and behaviour of different cell populations present in the tumour immune microenvironment, and the context-dependent functions of this cytokine in suppressing or promoting cancer. During homeostasis, TGFβ controls inflammatory responses triggered by exposure to the outside milieu in barrier tissues. Lack of TGFβ exacerbates inflammation, leading to tissue damage and cellular transformation. In contrast, as tumours progress, they leverage TGFβ to drive an unrestrained wound-healing programme in cancer-associated fibroblasts, as well as to suppress the adaptive immune system and the innate immune system. In consonance with this key role in reprogramming the tumour microenvironment, emerging data demonstrate that TGFβ-inhibitory therapies can restore cancer immunity. Indeed, this approach can synergize with other immunotherapies - including immune checkpoint blockade - to unleash robust antitumour immune responses in preclinical cancer models. Despite initial challenges in clinical translation, these findings have sparked the development of multiple therapeutic strategies that inhibit the TGFβ pathway, many of which are currently in clinical evaluation.

Roles of Mesenchymal Cells in the Lung: From Lung Development to Chronic Obstructive Pulmonary Disease

Mesenchymal cells are an essential cell type because of their role in tissue support, their multilineage differentiation capacities and their potential clinical applications. They play a crucial role during lung development by interacting with airway epithelium, and also during lung regeneration and remodeling after injury. However, much less is known about their function in lung disease. In this review, we discuss the origins of mesenchymal cells during lung development, their crosstalk with the epithelium, and their role in lung diseases, particularly in chronic obstructive pulmonary disease.

Mechanisms of Hypoxia-Induced Pulmonary Arterial Stiffening in Mice Revealed by a Functional Genetics Assay of Structural, Functional, and Transcriptomic Data

Hypoxia adversely affects the pulmonary circulation of mammals, including vasoconstriction leading to elevated pulmonary arterial pressures. The clinical importance of changes in the structure and function of the large, elastic pulmonary arteries is gaining increased attention, particularly regarding impact in multiple chronic cardiopulmonary conditions. We establish a multi-disciplinary workflow to understand better transcriptional, microstructural, and functional changes of the pulmonary artery in response to sustained hypoxia and how these changes inter-relate. We exposed adult male C57BL/6J mice to normoxic or hypoxic (FiO₂ 10%) conditions. Excised pulmonary arteries were profiled transcriptionally using single cell RNA sequencing, imaged with multiphoton microscopy to determine microstructural features under in vivo relevant multiaxial loading, and phenotyped biomechanically to quantify associated changes in material stiffness and vasoactive capacity. Pulmonary arteries of hypoxic mice exhibited an increased material stiffness that was likely due to collagen remodeling rather than excessive deposition (fibrosis), a change in smooth muscle cell phenotype reflected by decreased contractility and altered orientation aligning these cells in the same direction as the remodeled collagen fibers, endothelial proliferation likely representing endothelial-to-mesenchymal transitioning, and a network of cell-type specific transcriptomic changes that drove these changes. These many changes resulted in a system-level increase in pulmonary arterial pulse wave velocity, which may drive a positive feedback loop exacerbating all changes. These findings demonstrate the power of a multi-scale genetic-functional assay. They also highlight the need for systems-level analyses to determine which of the many changes are clinically significant and may be potential therapeutic targets.

TGFβ-Neurotrophin Interactions in Heart, Retina, and Brain

Ischemic insults to the heart and brain, i.e., myocardial and cerebral infarction, respectively, are amongst the leading causes of death worldwide. While there are therapeutic options to allow reperfusion of ischemic myocardial and brain tissue by reopening obstructed vessels, mitigating primary tissue damage, post-infarction inflammation and tissue remodeling can lead to secondary tissue damage. Similarly, ischemia in retinal tissue is the driving force in the progression of neovascular eye diseases such as diabetic retinopathy (DR) and age-related macular degeneration (AMD), which eventually lead to functional blindness, if left untreated. Intriguingly, the easily observable retinal blood vessels can be used as a window to the heart and brain to allow judgement of microvascular damages in diseases such as diabetes or hypertension. The complex neuronal and endocrine interactions between heart, retina and brain have also been appreciated in myocardial infarction, ischemic stroke, and retinal diseases. To describe the intimate relationship between the individual tissues, we use the terms heart-brain and brain-retina axis in this review and focus on the role of transforming growth factor β (TGFβ) and neurotrophins in regulation of these axes under physiologic and pathologic conditions. Moreover, we particularly discuss their roles in inflammation and repair following ischemic/neovascular insults. As there is evidence that TGFβ signaling has the potential to regulate expression of neurotrophins, it is tempting to speculate, and is discussed here, that cross-talk between TGFβ and neurotrophin signaling protects cells from harmful and/or damaging events in the heart, retina, and brain.

Transforming growth factor β3 deficiency promotes defective lipid metabolism and fibrosis in murine kidney

Glomerulosclerosis and tubulointerstitial fibrosis are pathological features of chronic kidney disease. Transforming growth factor β (TGFβ) is a key player in the development of fibrosis. However, of the three known TGFβ isoforms, only TGFβ1 has an established role in fibrosis, and the pathophysiological relevance of TGFβ2 and TGFβ3 is unknown. Because Tgfb3 deficiency in mice results in early postnatal lethality, we analyzed the kidney phenotype of heterozygous Tgfb3-knockout mice (Tgfb3^+/−) and compared it with that of matched wild-type mice. Four-month-old Tgfb3^+/− mice exhibited incipient renal fibrosis with epithelial–mesenchymal transition, in addition to glomerular basement membrane thickening and podocyte foot process effacement associated with albuminuria. Also evident was insulin resistance and oxidative stress at the renal level, together with aberrant renal lipid metabolism and mitochondrial function. Omics analysis revealed toxic species, such as diacylglycerides and ceramides, and dysregulated mitochondrial metabolism in Tgfb3^+/− mice. Kidneys of Tgfb3^+/− mice showed morphological alterations of mitochondria and overactivation of non-canonical MAPK ERK1/2 and JNK cascades. Our study indicates that renal TGFβ3 might have antifibrotic and renoprotective properties, opposing or counteracting the activity of TGFβ1.

This article has an associated First Person interview with the first author of the paper.

Summary: Our study describes the renal abnormalities of heterozygous Tgfb3-targeted mice and suggests that TGFβ3 is renoprotective and may counteract the activity of TGFβ1.

TGFβ2 and TGFβ3 isoforms drive fibrotic disease pathogenesis

Transforming growth factor-β (TGFβ) is a key driver of fibrogenesis. Three TGFβ isoforms (TGFβ1, TGFβ2, and TGFβ3) in mammals have distinct functions in embryonic development; however, the postnatal pathological roles and activation mechanisms of TGFβ2 and TGFβ3 have not been well characterized. Here, we show that the latent forms of TGFβ2 and TGFβ3 can be activated by integrin-independent mechanisms and have lower activation thresholds compared to TGFβ1. Unlike TGFB1, TGFB2 and TGFB3 expression is increased in human lung and liver fibrotic tissues compared to healthy control tissues. Thus, TGFβ2 and TGFβ3 may play a pathological role in fibrosis. Inducible conditional knockout mice and anti-TGFβ isoform-selective antibodies demonstrated that TGFβ2 and TGFβ3 are independently involved in mouse fibrosis models in vivo, and selective TGFβ2 and TGFβ3 inhibition does not lead to the increased inflammation observed with pan-TGFβ isoform inhibition. A cocrystal structure of a TGFβ2-anti-TGFβ2/3 antibody complex reveals an allosteric isoform-selective inhibitory mechanism. Therefore, inhibiting TGFβ2 and/or TGFβ3 while sparing TGFβ1 may alleviate fibrosis without toxicity concerns associated with pan-TGFβ blockade.