TGF-β Family Research Articles

TGF-β and BMP signaling are associated with the transformation of glioblastoma to gliosarcoma and then osteosarcoma.

Gliosarcoma, an isocitrate dehydrogenase wildtype (IDH-WT) variant of glioblastoma, is defined by clonal biphasic differentiation into gliomatous and sarcomatous components. While the transformation from a glioblastoma to gliosarcoma is uncommon, the subsequent transformation to osteosarcoma is rare but may provide additional insights into the biology of these typically distinct cancers. We observed a patient initially diagnosed with glioblastoma, that differentiated into gliosarcoma at recurrence, and further evolved to osteosarcoma at the second relapse. Our objective was to characterize the molecular mechanisms of tumor progression associated with this phenotypic transformation. Tumor samples were collected at all 3 stages of disease and RNA sequencing was performed to capture their transcriptomic profiles. Sequential clonal evolution was confirmed by the maintenance of an identical PTEN mutation throughout the tumor differentiation using the TSO500 gene panel. Publicly available datasets and the Nanostring nCounter technology were used to validate the results. The glioblastoma tumor from this patient possessed mixed features of all 3 TCGA-defined transcriptomic subtypes of an IDH-WT glioblastoma and a proportion of osteosarcoma signatures were upregulated in the original tumor. Analysis showed that enhanced transforming growth factor-β (TGF-β) and bone morphogenic protein signaling was associated with tumor transformation. Regulatory network analysis revealed that TGF-β family signaling committed the lineage tumor to osteogenesis by stimulating the expression of runt-related transcription factor 2 (RUNX2), a master regulator of bone formation. This unusual clinical case provided an opportunity to explore the modulators of longitudinal sarcomatous transformation, potentially uncovering markers indicating predisposition to this change and identification of novel therapeutic targets.

Proteome Profiling of Brain Vessels in a Mouse Model of Cerebrovascular Pathology.

Cerebrovascular pathology that involves altered protein levels (or signaling) of the transforming growth factor beta (TGFβ) family has been associated with various forms of age-related dementias, including Alzheimer disease (AD) and vascular cognitive impairment and dementia (VCID). Transgenic mice overexpressing TGFβ1 in the brain (TGF mice) recapitulate VCID-associated cerebrovascular pathology and develop cognitive deficits in old age or when submitted to comorbid cardiovascular risk factors for dementia. We characterized the cerebrovascular proteome of TGF mice using mass spectrometry (MS)-based quantitative proteomics. Cerebral arteries were surgically removed from 6-month-old-TGF and wild-type mice, and proteins were extracted and analyzed by gel-free nanoLC-MS/MS. We identified 3602 proteins in brain vessels, with 20 demonstrating significantly altered levels in TGF mice. For total and/or differentially expressed proteins (p ≤ 0.01, ≥ 2-fold change), using multiple databases, we (a) performed protein characterization, (b) demonstrated the presence of their RNA transcripts in both mouse and human cerebrovascular cells, and (c) demonstrated that several of these proteins were present in human extracellular vesicles (EVs) circulating in blood. Finally, using human plasma, we demonstrated the presence of several of these proteins in plasma and plasma EVs. Dysregulated proteins point to perturbed brain vessel vasomotricity, remodeling, and inflammation. Given that blood-isolated EVs are novel, attractive, and a minimally invasive biomarker discovery platform for age-related dementias, several proteins identified in this study can potentially serve as VCID markers in humans.

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.

CXCR4 Enriched T Regulatory Cells Preferentially Home to Bone Marrow and Decrease Inflammation

Background and aim Adoptive therapy with T regulatory cells (Tregs) is emerging as an important therapeutic strategy for several autoimmune and inflammatory diseases. Optimal homing and payload delivery of these anti-inflammatory cells remain a cornerstone of optimizing their therapeutic efficacy. CXCR4 cell surface expression has been shown to be critical for homing of hematopoietic cells to the bone marrow (BM). Also, CXCR4/CXCL12 axis plays a major role in the pathogenesis of BM inflammatory disorders including myelofibrosis. We hypothesize that enrichment of CXCR4 on the Tregs cell surface will enable their trafficking to BM and ensure a homogenous delivery. Methods/results/conclusion Magnetic enrichment of CD25 + cells was performed on umbilical cord blood on day 0, followed by dual enrichment on CXCR4 using CRANE TM (cord blood Tregs, activated and enriched) process on day 3 or 4 (Fig 1A). The enrichment process led to increased number of Tregs expressing CXCR4 on their cell surface (Fig 1B; Treg CXCR4) as well as a CXCR4 hi Treg cells when compared to Treg control (Fig 1C, p<0.0001; n=16). In a Transwell TM system, a higher number of Treg CXCR4 migrated to the bottom well in chemotactic response to SDF1α at 15 minutes as compared to the Treg control cells. Such migration was inhibited by CXCR4 antagonist, AMD3100 (Fig 1D). The migration superiority of Treg CXCR4 was maintained at 30 and 60 min (Fig 1E). In order to understand in vivo transit kinetics, Treg cells were injected into NSG mice and organs were harvested at 12 and 24 hours (Fig 1F). Treg CXCR4 showed preferential homing to BM (Fig 1G), where a higher expression of CXCR4 and CXCL12 than control, was observed (Fig 1H). Other markers including CD62L (homing and suppression), CD39 & CD73 (conversion of ATP to immunosuppressive adenosine), and CXCR5 (Follicular Treg) were also increased in Treg CXCR4 recipients. A decrease in biomarkers including TGFα and TNFβ (inflammation), IL-13 (fibrosis) (Fig 1I) with an increase in GM-CSF (increase Treg potency) (Fig 1J), was observed in Treg CXCR4 recipients with a corresponding decrease in TGFβ family (hematopoietic suppressor) (Fig 1K). We conclude that Treg CXCR4 shows superior homing to BM and is currently being studied in a clinical setting to treat myelofibrosis with suboptimal response to ruxolitinib (NCT05423691).

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.

Genome-wide characterization of the TGF-β gene family and their expression in different tissues during tail regeneration in the Schlegel's Japanese gecko Gekko japonicus

The transforming growth factor-β (TGF-β) gene family is unique to animals and is involved in various important processes including tissue regeneration. Here, we identified 52 TGF-β family genes based on genome sequences of the gecko (Gekko japonicus), compared TGF-β genes between G. japonicus and other four reptilian species, and evaluated the expression of 14 randomly selected genes in muscle, kidney, liver, heart, and brain during tail regeneration to investigate whether their expression was tissue-dependent. We detected 23 conserved domains, 13 in the TGF-β ligand subfamily, and 10 in the receptor subfamily. The pattern of higher genetic variation in the ligand subfamily than in the receptor subfamily in vertebrates might result from the precise localization of agonists and antagonists in the cell surface and intracellular compartment. TGF-β genes were unevenly distributed across 15 chromosomes in G. japonicus, presumably resulting from gene losses and gains during evolution. Genes in the TGF-β receptor subfamily (ACVR2A, ACVR2B, ACVR1, BMPR1A, ACVRL1, BMPR2 and TGFBR1) played a vital role in the TGF-β signal pathway. The expression of all 14 randomly selected TGF-β genes was tissue-specific. Our study supports the speculation that some TGF-β family genes are involved in the early stages of tail regeneration.

Myostatin as a Prognostic Biomarker in Hepatic Cirrhosis Patients with Sarcopenia

Cirrhosis represents the advanced stage of numerous chronic liver conditions. Sarcopenia is a frequently overlooked complication in cirrhotic patients, resulting from factors such as insufficient protein intake, malabsorption, diminished muscle growth, and increased muscle breakdown. Sarcopenia is a multifaceted, chronic condition associated with elevated risks of morbidity and mortality. In the field of hepatology, sarcopenia is typically described as a phenotypic indication of muscle mass loss, affecting approximately 30-70% of liver cirrhosis patients. Sarcopenia has been scientifically linked to an increased risk of falls, reduced quality of life, the emergence of acute decompensated liver failure, and mortality in cirrhotic patients. Myostatin, classified as a cytokine within the transforming growth factor beta (TGF-β) family, is recognized for its role in disrupting protein synthesis. It functions as a negative regulator of muscle growth, inhibiting myogenesisand is linked to the onset of sarcopenia. Extensive literature supports the prognostic importance of sarcopenia in cirrhosis, and serum myostatin levels have the potential to serve as a valuable biomarker. Elevated myostatin concentrations have been linked to the presence of sarcopenia and decreased survival rates in individuals diagnosed with liver cirrhosis.

Endometrial TGFβ signaling fosters early pregnancy development by remodeling the fetomaternal interface.

The endometrium is a unique and highly regenerative tissue with crucial roles during the reproductive lifespan of a woman. As the first site of contact between mother and embryo, the endometrium, and its critical processes of decidualization and immune cell recruitment, play a leading role in the establishment of pregnancy, embryonic development, and reproductive capacity. These integral processes are achieved by the concerted actions of steroid hormones and a myriad of growth factor signaling pathways. This review focuses on the roles of the transforming growth factor β (TGFβ) pathway in the endometrium during the earliest stages of pregnancy through the lens of immune cell regulation and function. We discuss how key ligands in the TGFβ family signal through downstream SMAD transcription factors and ultimately remodel the endometrium into a state suitable for embryo implantation and development. We also focus on the key roles of the TGFβ signaling pathway in recruiting uterine natural killer cells and their collective remodeling of the decidua and spiral arteries. By providing key details about immune cell populations and TGFβ signaling within the endometrium, it is our goal to shed light on the intricate remodeling that is required to achieve a successful pregnancy.

MicroRNA Expression Patterns Reveal a Role of the TGF-β Family Signaling in AML Chemo-Resistance.

Resistance to chemotherapy is ultimately responsible for the majority of AML-related deaths, making the identification of resistance pathways a high priority. Transcriptomics approaches can be used to identify genes regulated at the level of transcription or mRNA stability but miss microRNA-mediated changes in translation, which are known to play a role in chemo-resistance. To address this, we compared miRNA profiles in paired chemo-sensitive and chemo-resistant subclones of HL60 cells and used a bioinformatics approach to predict affected pathways. From a total of 38 KEGG pathways implicated, TGF-β/activin family signaling was selected for further study. Chemo-resistant HL60 cells showed an increased TGF-β response but were not rendered chemo-sensitive by specific inhibitors. Differential pathway expression in primary AML samples was then investigated at the RNA level using publically available gene expression data in the TGCA database and by longitudinal analysis of pre- and post-resistance samples available from a limited number of patients. This confirmed differential expression and activity of the TGF-β family signaling pathway upon relapse and revealed that the expression of TGF-β and activin signaling genes at diagnosis was associated with overall survival. Our focus on a matched pair of cytarabine sensitive and resistant sublines to identify miRNAs that are associated specifically with resistance, coupled with the use of pathway analysis to rank predicted targets, has thus identified the activin/TGF-β signaling cascade as a potential target for overcoming resistance in AML.

Weak response of bovine hepcidin induction to iron through decreased expression of Smad4.

Hepcidin negatively regulates systemic iron levels by inhibiting iron entry into the circulation. Hepcidin production is increased in response to an increase in systemic iron via the activation of the bone morphogenetic protein (BMP) pathway. Regulation of hepcidin expression by iron status has been proposed on the basis of evidence mainly from rodents and humans. We evaluated the effect of iron administration on plasma hepcidin concentrations in calves and the expression of bovine hepcidin by the BMP pathway in a cell culture study. Hematocrit as well as levels of blood hemoglobin and plasma iron were lower than the reference level in calves aged 1-4 weeks. Although intramuscular administration of iron increased iron-related parameters, plasma hepcidin concentrations were unaffected. Treatment with BMP6 increased hepcidin expression in human liver-derived cells but not in bovine liver-derived cells. A luciferase-based reporter assay revealed that Smad4 was required for hepcidin reporter transcription induced by Smad1. The reporter activity of hepcidin was lower in the cells transfected with bovine Smad4 than in those transfected with murine Smad4. The lower expression levels of bovine Smad4 were responsible for the lower activity of the hepcidin reporter, which might be due to the instability of bovine Smad4 mRNA. In fact, the endogenous Smad4 protein levels were lower in bovine cells than in human and murine cells. Smad4 also confers TGF-β/activin-mediated signaling. Induction of TGF-β-responsive genes was also lower after treatment with TGF-β1 in bovine hepatocytes than in human hepatoma cells. We revealed the unique regulation of bovine hepcidin expression and the characteristic TGF-β family signaling mediated by bovine Smad4. The present study suggests that knowledge of the regulatory expression of hepcidin as well as TGF-β family signaling obtained in murine and human cells is not always applicable to bovine cells.

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.

SAT662 Bone Morphogenetic Protein 7 Induces Transdifferentiation Of Human White Preadipocytes Into Thermogenic Beige Adipocytes

Abstract Disclosure: S.L. Ali: None. J. Katz: None. A.M. Cypess: None. Chronic treatment of women with mirabegron, which activates the β3-adrenergic receptor, increases the mass and energy expenditure of thermogenic adipocytes and leads to metabolic benefits including improvement of glucose and lipid homeostasis. In humans, thermogenic adipose tissue is composed of brown and beige/brite (from “brown-in-white”) cells that have different lineages and potentially different functions. Beige cells are of therapeutic interest because they are derived from white adipose tissue, which is present at a considerably higher volume compared to brown adipose tissue. Identifying processes that can transdifferentiate white into beige cells could lead to treatments for obesity-related metabolic disease. We hypothesized that short-term treatment with bone morphogenetic protein 7 (BMP7), a member of the transforming growth factor-β (TGF-β) family of cell regulatory proteins, prior to differentiation could be sufficient to induce white to beige transition in human white preadipocytes. We established paired clonal immortalized human white and brown preadipocyte lines and differentiated the white adipocytes ± BMP7 (3.3 nM) for 7 days prior to differentiation. Cells were collected at d0 (undifferentiated) and d30 (fully mature adipocytes) for gene expression analyses. Short-term exposure to BMP7 in white preadipocytes significantly decreased the expression of white-specific markers TCF21 and HOXC8. The beige-specific markers TBX1 and TMEM26, and the thermogenic marker UCP1 were significantly higher in BMP7-treated white adipocytes. However, long term, 30-day exposure to BMP7 treatment reversed the thermogenic transdifferentiation both human white and brown adipocytes. Basal and drug-induced maximal respiration measured via Seahorse XFe96 Analyzer were significantly higher in short-term BMP7-treated white adipocytes. Our data indicate that BMP7 is capable of transdifferentiating human white preadipocytes into thermogenic beige adipocytes. Given that extended treatment reduced the impact of BMP7 indicates that precise timing of interventions will be needed to utilize white-to-beige transdifferentiation to treat obesity-associated metabolic disease. Presentation: Saturday, June 17, 2023

SAT267 BMP4, GDF11 And TGFβ2 Repress Adrenal Cell Cortisol Production By Blocking CYP17A1 And CYP11B1 Expression

Abstract Disclosure: E.C. Fischbach: None. A. Lopez: None. M. Ullenbruch: None. J. Rege: None. W.E. Rainey: None. Introduction: The adrenal cortex is responsible for the biosynthesis of multiple steroid hormones that regulate electrolyte and carbohydrate balance. Cortisol, the principal glucocorticoid in humans, is primarily produced in the middle zone of the cortex known as the zona fasciculata (ZF). The enzymes responsible for cortisol biosynthesis include cytochrome P450c17 (17α-hydroxylase), encoded by CYP17A1 and cytochrome P450c11 (11β-hydroxylase), encoded by CYP11B1. Several paracrine/autocrine regulators, including members of the transforming growth factor beta (TGFβ) superfamily, have been implicated in controlling adrenocortical cell homeostasis and steroid hormone production. Previously, we reported a bone morphogenetic protein 4 (BMP4) expression gradient in the adrenal cortex with higher levels in the zona glomerulosa (ZG) and outer ZF compared to the zona reticularis (ZR). In this study, we sought to compare adrenal expression of members of the TGFβ family including BMP4, growth differentiation factor 11 (GDF11), and transforming growth factor beta 2 (TGFβ2), and determine their effect on adrenal cell cortisol biosynthesis. Methods: Growth factor mRNA levels were studied using microarray analysis of laser captured ZG, ZF and ZR from human adrenals. The adrenal cell line, HAC15 was used to determine the effects of the TGFβ family members alone and in combination. Output measures included cell cortisol production and mRNA levels of steroidogenic enzymes using ELISA and quantitative RT-PCR, respectively. Results: Microarray analysis indicated higher mRNA levels of BMP4, GDF11 and TGFβ2 in the ZG compared with the ZF and ZR regions of the adrenal. Treatment of HAC15 cells with either BMP4 (50 ng/mL), GDF11 (50 ng/mL) or TGFβ2 (10 ng/mL) significantly inhibited cortisol production, as well as CYP11B1 and CYP17A1 mRNA levels. The inhibition was observed under basal and forskolin-stimulated conditions. Furthermore, the inhibitory effects on cortisol production and enzyme expression were additive when factors were added together. Summary: Overall, our findings suggest that the human adrenal has a gradient of multiple members of the TGFβ family. The additive action of these growth factors on adrenal cell differentiation may explain, in part, the inability of the ZG to produce cortisol and its low expression of CYP11B1 and CYP17A1. Presentation: Saturday, June 17, 2023

OR09-03 Loss of Inhibin Negative Feedback In The Pituitary Leads To Enhanced Ovulation But Pregnancy Failure In Mice

Abstract Disclosure: Y. Lin: None. E. Brule: None. M. Cowan: None. U. Boehm: None. D.J. Bernard: None. Loss of inhibin negative feedback in the pituitary leads to enhanced ovulation but pregnancy failure in mice Follicle-stimulating hormone (FSH) is an essential regulator of gonadal function, particularly in females. Inhibins are TGFβ family ligands made in the gonads that suppress FSH synthesis. Inhibins require a co-receptor, betaglycan or TGFBR3L, to mediate their actions in pituitary gonadotrope cells. Female mice with a gonadotrope-specific knockout of betaglycan or global deletion of Tgfbr3l exhibit increased ovarian follicle development, numbers of ovulated eggs, and litter sizes compared to controls. Females with both co-receptors knocked out (hereafter dKO) show dramatic increases in FSH levels, numbers of antral follicles and corpora lutea, serum progesterone levels, and ovarian aromatase expression. They ovulate 3-4 times as many eggs in natural cycles compared to control females. dKO females can become pregnant and show an increased number of implanted embryos at 7.5 days post coitum (7.5 dpc). Nevertheless, dKO females do not give birth to live offspring. By 10.5 dpc, the weight of the fetoplacental unit is decreased in dKO females, and many embryos display morphological abnormalities. By 14.5 dpc, most embryos in dKO females are either dead or resorbing. Wild-type surrogates give birth to live young following transplantation of embryos from control or dKO females. Conversely, control but not dKO females carry wild-type embryos to term. These data suggest that the maternal environment in dKO mice cannot support full-term pregnancies. Based on the hormonal profile of the cycling females, we suspected a deleterious effect of elevated estrogens. Consistent with this idea, treatment with the aromatase inhibitor anastrozole increased fetal survival in some dKO mice, suggesting a role for estrogens in embryo death. We are currently more thoroughly characterizing the maternal hormonal environment throughout gestation and investigating placental structure/function to gain more insight into the precise nature of the pregnancy failure. Our results will show how loss of inhibin action in the pituitary impede embryo survival and whether pregnancy loss is linked to increases in FSH. Presentation: Friday, June 16, 2023

Genome-wide analysis of BMP/GDF family and DAP-seq of YY1 suggest their roles in Cynoglossus semilaevis sexual size dimorphism

Sexual size dimorphism (SSD) characterized by different body size between females and males have been reported in various animals. Gonadectomy experiments have implied important regulatory roles of the gonad in SSD. Among multiple factors from the gonad, TGF-β superfamily (especially BMP/GDF family) attracted our interest due to its pleiotropy in growth and reproduction regulations. Thus, whether BMP/GDF family members serve as crucial regulators for SSD was studied in a typically female-biased SSD flatfish named Chinese tongue sole (Cynoglossus semilaevis). Firstly, a total of 26 BMP/GDF family members were identified. The PPI network analysis showed that they may interact with ACVR2a, ACVR2b, ACVR1, BMPR2, SMAD3, BMPR1a, and other proteins. Subsequently, DAP-seq was employed to reveal the binding sites for yin yang 1 (yy1), a transcription factor involved in gonad function and cell growth partly by regulating TGF-β superfamily. The results revealed that two yy1 homologues yy1a and yy1b in C. semilaevis could regulate Hippo signaling pathway, mTOR signaling pathway, and AMPK signaling pathway. Moreover, BMP/GDF family genes including bmp2, bmp4, bmp5, gdf6a, and gdf6b were important components of Hippo pathway. In future, the crosstalk among yy1a, yy1b, and TGF-β family would provide more insight into sexual size dimorphism in C. semilaevis.

Circulating Growth Differentiation Factor 15 as a Biomarker in Patients with Unresected Locally Advanced Non-Small Cell Lung Cancer Treated with Chemo-Radiotherapy with or without Metformin

Growth differentiation factor 15 (GDF15) is a member of the TGFβ family suggested to have prognostic value in cancer. Plasma GDF15 levels are elevated in humans during cellular stress, chronic diseases, and cancer and in response to cytotoxic (chemotherapy and radiation) or metabolic (metformin) therapies. Currently, the effect of combined metformin and cytotoxic treatment on circulating GDF15 is not known, and it is unclear whether GDF15 can serve as a biomarker in patients receiving such therapy. To examine this question, we analyzed circulating GDF15 levels in stage IIIA or IIIB NSCLC patients that participated in the randomized phase II clinical trial OCOG-ALMERA (NCT02115464). In OCOG-ALMERA patients were randomized to treatment with concurrent platinum-based chemotherapy and chest radiotherapy (60-66 Gy), with or without consolidation chemotherapy (CRT) or the same treatment plus metformin (2000mg/d). Dosimetric parameters and survival outcomes were collected by the trial. EDTA Plasma was collected from patients at baseline, 2 weeks into CRT treatment, at completion of CRT and 6 months after treatment initiation and assayed for GDF15 using an ELISA method. Statistical analyses were conducted to explore potential associations between plasma GDF15 with survival and dosimetric parameters. Fifteen patients from the metformin arm and 18 from the control arms provided EDTA plasma for this analysis. Average baseline GDF15 levels for all participants were elevated compared to those reported for healthy individuals. Baseline plasma GDF15 was statistically prognostic for RFS and OS (hazard ratio = 1.19, 95% CI = 1.06 to 1.34, p = 0.005). GDF15 levels increased during CRT treatment reaching the highest value at the end of cytotoxic therapy. Addition of metformin to CRT treatment was associated with further increase in circulating GDF15 (p<0.001). Plasma GDF15 levels at 2 weeks of CRT were positively correlated with size of the radiotherapy clinical target volume and volumes of esophagus and heart receiving high dose radiotherapy. This work suggests that GDF15 may be a promising prognostic marker to predict response to standard chemoradiation therapy in NSCLC. Future studies should aim to validate these results in larger datasets and examine whether GDF15 may have value as early biomarker of radiation toxicity in lung cancer patients.

Tonic activin signaling shapes cellular and synaptic properties of CA1 neurons mainly in dorsal hippocampus

Dorsal and ventral hippocampus serve different functions in cognition and affective behavior, but the underpinnings of this diversity at the cellular and synaptic level are not well understood. We found that the basal level of activin A, a member of the TGF-β family, which regulates hippocampal circuits in a behaviorally relevant fashion, is much higher in dorsal than in ventral hippocampus. Using transgenic mice with a forebrain-specific disruption of activin receptor signaling, we identified the pronounced dorsal-ventral gradient of activin A as a major factor determining the distinct neurophysiologic signatures of dorsal and ventral hippocampus, ranging from pyramidal cell firing, tuning of frequency-dependent synaptic facilitation, to long-term potentiation (LTP), long-term depression (LTD), and de-potentiation. Thus, the strong activin A tone in dorsal hippocampus appears crucial to establish cellular and synaptic phenotypes that are tailored specifically to the respective network operations in dorsal and ventral hippocampus.

Ligand-specific regulation of transforming growth factor beta superfamily factors by leucine-rich repeats and immunoglobulin-like domains proteins.

Leucine-rich repeats and immunoglobulin-like domains (LRIG) are transmembrane proteins shown to promote bone morphogenetic protein (BMP) signaling in Caenorhabditis elegans, Drosophila melanogaster, and mammals. BMPs comprise a subfamily of the transforming growth factor beta (TGFβ) superfamily, or TGFβ family, of ligands. In mammals, LRIG1 and LRIG3 promote BMP4 signaling. BMP6 signaling, but not BMP9 signaling, is also regulated by LRIG proteins, although the specific contributions of LRIG1, LRIG2, and LRIG3 have not been investigated, nor is it known whether other mammalian TGFβ family members are regulated by LRIG proteins. To address these questions, we took advantage of Lrig-null mouse embryonic fibroblasts (MEFs) with doxycycline-inducible LRIG1, LRIG2, and LRIG3 alleles, which were stimulated with ligands representing all the major TGFβ family subgroups. By analyzing the signal mediators pSmad1/5 and pSmad3, as well as the induction of Id1 expression, we showed that LRIG1 promoted BMP2, BMP4, and BMP6 signaling and suppressed GDF7 signaling; LRIG2 promoted BMP2 and BMP4 signaling; and LRIG3 promoted BMP2, BMP4, BMP6, and GDF7 signaling. BMP9 and BMP10 signaling was not regulated by individual LRIG proteins, however, it was enhanced in Lrig-null cells. LRIG proteins did not regulate TGFβ1-induced pSmad1/5 signaling, or GDF11- or TGFβ1-induced pSmad3 signaling. Taken together, our results show that some, but not all, TGFβ family ligands are regulated by LRIG proteins and that the three LRIG proteins display differential regulatory effects. LRIG proteins thereby provide regulatory means for the cell to further diversify the signaling outcomes generated by a limited number of TGFβ family ligands and receptors.

Context-dependent TGFβ family signalling in cell fate regulation.

The transforming growth factor-β (TGFβ) family are a large group of evolutionarily conserved cytokines whose signalling modulates cell fate decision-making across varying cellular contexts at different stages of life. Here we discuss new findings in early embryos that reveal how, in contrast to our original understanding of morphogen interpretation, robust cell fate specification can originate from a noisy combination of signalling inputs and a broad range of signalling levels. We compare this evidence with novel findings on the roles of TGFβ family signalling in tissue maintenance and homeostasis during juvenile and adult life, spanning the skeletal, haemopoietic and immune systems. From these comparisons, it emerges that in contrast to robust developing systems, relatively small perturbations in TGFβ family signalling have detrimental effects at later stages in life, leading to aberrant cell fate specification and disease, for example in cancer or congenital disorders. Finally, we highlight novel strategies to target and amend dysfunction in signalling and discuss how gleaning knowledge from different fields of biology can help in the development of therapeutics for aberrant TGFβ family signalling in disease.

The projection-specific signals that establish functionally segregated dopaminergic synapses

Dopaminergic projections regulate various brain functions and are implicated in many neuropsychiatric disorders. There are two anatomically and functionally distinct dopaminergic projections connecting the midbrain to striatum: nigrostriatal, which controls movement, and mesolimbic, which regulates motivation. However, how these discrete dopaminergic synaptic connections are established is unknown. Through an unbiased search, we identify that two groups of antagonistic TGF-β family members, bone morphogenetic protein (BMP)6/BMP2 and transforming growth factor (TGF)-β2, regulate dopaminergic synapse development of nigrostriatal and mesolimbic neurons, respectively. Projection-preferential expression of their receptors contributes to specific synapse development. Downstream, Smad1 and Smad2 are specifically activated and required for dopaminergic synapse development and function in nigrostriatal vs. mesolimbic projections. Remarkably, Smad1 mutant mice show motor defects, whereas Smad2 mutant mice show lack of motivation. These results uncover the molecular logic underlying the proper establishment of functionally segregated dopaminergic synapses and may provide strategies to treat relevant, projection-specific disease symptoms by targeting specific BMPs/TGF-β and/or Smads.