Activins and Inhibins: Roles in Development, Physiology, and Disease

Sotatercept in pulmonary hypertension and beyond

Sotatercept binds free activins by mimicking the extracellular domain of the activin receptor type IIA (ACTRIIA). Additional ligands are BMP/TGF-beta, GDF8, GDF11 and BMP10. The binding with activins leads to the inhibition of the signalling pathway and the deactivation of the bone morphogenic protein (BMP) receptor type 2. In this way, sotatercept activates an antiproliferative signalling to the cells of the pulmonary arteries and arterioles with the aim of rebalancing the proliferative and antiproliferative pathway that characterizes the pulmonary arterial hypertension (PAH). Sotatercept is indicated for the treatment of group 1 PAH in combination with drugs that act through the endothelin receptor, nitric oxide or prostacyclin. Its effects, demonstrated in the STELLAR study, are the improvement of exercise capacity and the FC-WHO functional class, together with the reduction of the risk of clinical worsening events. In addition to its antiremodeling effects on the pulmonary circulation, sotatercept has several haematological effects that could suggest its use in the treatment of some blood disorders other than PAH. In this review, we will discuss the effects of the drug on PAH and in parallel provide an in-depth overview of its application in haematological disorders, focusing on clinical and preclinical studies.

Activin B improves glucose metabolism via induction of Fgf21 and hepatic glucagon resistance

Orchestrated hormonal interactions in response to feeding and fasting play a pivotal role in regulating glucose homeostasis. Here, we show that in obesity, the production of follistatin-like 3 (FSTL3), an endogenous inhibitor of Activin B, in adipose tissue is increased in both mice and humans. The knockdown of FSTL3 improves insulin sensitivity and glucose tolerance in diabetic obese db/db mice. Notably, the overexpression of Activin B, a member of the TGFβ superfamily that is induced in liver sinusoidal endothelial cells by fasting, exerts multiple metabolically beneficial effects, including improvement of insulin sensitivity, suppression of hepatic glucose production, and enhancement of glucose-stimulated insulin secretion, all of which are attenuated by the overexpression of FSTL3. Activin B increases insulin sensitivity and reduces fat by inducing fibroblast growth factor 21 (FGF21) while suppressing glucagon action in the liver by increasing phosphodiesterase 4 B (PDE4B), leading to hepatic glucagon resistance and resultant hyperglucagonemia. Activin B-induced hyperglucagonemia enhances glucose-stimulated insulin secretion by stimulating glucagon-like peptide-1 (GLP-1) receptor in pancreatic β-cells. Thus, enhancing the action of Activin B which improves multiple components of the pathogenesis of diabetes may be a promising strategy for diabetes treatment.

Retrograde mitochondrial signaling governs the identity and maturity of metabolic tissues

Mitochondrial damage is a hallmark of metabolic diseases, including diabetes, yet the consequences of compromised mitochondria in metabolic tissues are often unclear. In this work, we report that dysfunctional mitochondrial quality control engages a retrograde (mitonuclear) signaling program that impairs cellular identity and maturity in β cells, hepatocytes, and brown adipocytes. Targeted deficiency throughout the mitochondrial quality control pathway, including genome integrity, dynamics, or turnover, impaired the oxidative phosphorylation machinery, activating the mitochondrial integrated stress response, eliciting chromatin remodeling, and promoting cellular immaturity rather than apoptosis to yield metabolic dysfunction. Pharmacologic blockade of the integrated stress response in vivo restored β cell identity after the loss of mitochondrial quality control. Targeting mitochondrial retrograde signaling may therefore be promising in the treatment or prevention of metabolic disorders.

Skin microbiome influences the progression of cutaneous squamous cell carcinoma through the immune system

Cutaneous squamous cell carcinoma (cSCC) is a type of skin tumor that develops in the epithelial cells. This disease has the second highest incidence of human skin cancers, with a high metastatic rate. While ultraviolet radiation significantly contributes to the genomic changes that support cSCC development, the dysbiosis of the skin microbiome and influence of the immune system also play important roles in this process. In this review, we discuss the effects of skin microbes and their metabolites on the immune system, including innate immune cells, T cells, and cytokines. We also discuss how Staphylococcus aureus and human papillomavirus can affect cSCC by impacting the immune system. Furthermore, we explore the antagonism of symbiotic microorganisms with cSCC-associated pathogens and their potential as novel therapeutic modalities.

Deleterious variants in intolerant genes reveal new candidates for self-limited delayed puberty

OBJECTIVE

Self-limited delayed puberty (SLDP) is the most common cause of delayed puberty and exhibits high heritability, although few causal genes have been identified. This study aims to identify potential candidate genes associated with SLDP.

METHODS

Whole-exome sequencing was conducted in 71 children with SLDP, most of whom presented with short stature. Rare coding variants were prioritized through comprehensive bioinformatics analyses and classified as high-impact or moderate-impact based on predicted functional effects. Candidate genes were selected based on the absence of human phenotype data, recurrence within the cohort, intolerance to mutation, and prior identification in genome-wide association studies. Burden tests compared the frequency of rare high-impact variants in these candidate genes between SLDP patients and the gnomAD v2.0 control group. Gene-phenotype associations were further explored using UK Biobank data.

RESULTS

Fourteen high-impact and 7 moderate-impact variants were identified in 19 candidate genes, suggesting a potential role in SLDP. Variants in 8 candidate genes (GPS1, INHBB, SP3, NAMPT, ARID3B, NASP, FNBP1, PRDM2) were significantly enriched in cases compared to controls in the burden test analysis. INHBB was additionally linked to delayed menarche in UK Biobank data. Furthermore, 3 pathogenic variants (CDK13, GDF5, ANRKD11) and 6 likely pathogenic variants (TYMP, DPF2, KMT2C, TP63, MC3R, GHSR) previously associated with growth or pubertal human disorders were identified.

CONCLUSION

These findings suggest that SLDP involves both monogenic and polygenic mechanisms, with novel candidate genes contributing to its genetic basis. The association of INHBB with pubertal timing underscores its potential role in SLDP pathophysiology.

CellPhoneDB v5: inferring cell-cell communication from single-cell multiomics data

Cell-cell communication is essential for tissue development, function and regeneration. The revolution of single-cell genomics technologies offers an unprecedented opportunity to uncover how cells communicate in vivo within their tissue niches and how disruption of these niches can lead to diseases and developmental abnormalities. CellPhoneDB is a bioinformatics toolkit designed to infer cell-cell communication by combining a curated repository of bona fide ligand-receptor interactions with methods to integrate these interactions with single-cell genomics data. Here we present a protocol for the latest version of CellPhoneDB (v5), offering several new features. First, the repository has been expanded by one-third with the addition of new interactions, including ~1,000 interactions mediated by nonpeptidic ligands such as steroidogenic hormones, neurotransmitters and small G-protein-coupled receptor (GPCR)-binding ligands. Second, we outline a new way of using the database that allows users to tailor queries to their experimental designs. Third, the update incorporates novel strategies to prioritize specific cell-cell interactions, leveraging information from other modalities such as tissue microenvironments derived from spatial transcriptomics technologies or transcription factor activities derived from a single-cell assay for transposase accessible chromatin assays. Finally, we describe the new CellPhoneDBViz module to interactively visualize and share results. Altogether, CellPhoneDB v5 enhances the precision of cell-cell communication inference, offering new insights into tissue biology in physiological microenvironments. This protocol typically takes ~15 min and requires basic knowledge of python.

An Arrayed CRISPR Screen Identifies Knockout Combinations Improving Antibody Productivity in HEK293 Cells

Mammalian cells are used to express complex biologics, such as multispecific antibodies. While multispecifics enable promising new strategies for treating human disease, their production at high expression titer and purity can be challenging. To understand how cells respond to antibody and multispecific expression, five molecules were selected for bulk RNA sequencing (RNA-seq) early after the transfection of a human embryonic kidney 293 (HEK293) host. All five molecules shared a differential expression signature of secretory and protein folding stresses, but this signature was stronger for molecules with low titer. We then designed an arrayed CRISPR knockout screen of 206 differentially expressed target genes and 223 literature-motivated targets to identify knockouts that affect antibody productivity. Eight novel knockout targets were identified that increased expression titers by 20-80%. Notably, seven of these top eight hits were from the differentially expressed set of candidate-gene knockouts. The top knockout target, HIST2H3C, showed evidence for additivity with five other hits, including a knockout combination that increased the titer of a difficult-to-express antibody by up to 100%. Findings for both HIST2H3C and INHBE knockout targets generalized to an alternate HEK293 host expressing an additional antibody and a multispecific host with no meaningful impact on product purity. Thus, we propose HIST2H3C and INHBE disruption as a promising and novel strategy for host-cell engineering to improve antibody and multispecific productivity.

Activin a regulates vascular formation and stabilization in direct coculture of dental pulp stem cells and endothelial cells

AIM

Establishing functional circulation on time is crucial to dental pulp tissue regeneration. Mesenchymal stem cells (MSCs) could act as mural cells to stabilize newly formed blood vessels, accelerating anastomosis. Our preliminary study found that direct coculture of dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) significantly enhanced Activin A secretion. This study aimed to disclose the dynamic patterns of Activin A expression and its regulation on vascular formation and stabilization.

METHODOLOGY

DPSCs and HUVECs were cocultured directly at a ratio of 1:1 for 3 and 6 days. Activin A and Follistatin expression were evaluated by qRT-PCR and ELISA. HUVECs were exposed to 100 ng/mL Activin A or the conditioned medium (CM) generated from DPSC monoculture and DPSC-HUVEC coculture, respectively. HUVEC proliferation, migration, tube formation and angiogenic sprouting were assessed. In parallel, membrane-bound vascular endothelial growth factor receptors (mVEGFR1 and mVEGFR2) and soluble VEGFR1 (sVEGFR1) were analysed at days 3 and 6.

RESULTS

Activin A expression and secretion were elevated time-dependently during DPSC-HUVEC coculture. Follistatin expression decreased in DPSC-HUVEC coculture while the ratio of Activin A/Follinstain increased significantly. Activin A treatment did not promote DPSC towards smooth muscle cell (SMC)-specific differentiation, while Activin A and DPSC+HUVEC-CM suppressed HUVEC proliferation, migration, tube formation and sprouting. Activin A and DPSC+HUVEC-CM treatment markedly increased mVEGFR1 expression and sVEGFR1 secretion, suppressing HUVEC vascular formation. Activin A IgG partially reversed the effects of DPSC+HUVEC-CM on HUVECs by decreasing VEGFR1 expression and increasing vessel formation. Activin A pretreatment downregulated VEGF-triggered VEGFR2 phosphorylation of HUVECs. INHBA knockdown DPSCs disrupted the stabilization of the preformed HUVEC vascular tube network.

CONCLUSION

DPSC-HUVEC direct coculture upregulates Activin A secretion, interrupting VEGF receptors' balance in HUVECs to suppress HUVEC angiogenic sprouting and enhance vascular stabilization. These findings provide novel insights into the paracrine interactions on vascular stabilization of DPSC-HUVEC direct coculture.

Activin A Inhibitory Peptides Suppress Fibrotic Pathways by Targeting Epithelial-Mesenchymal Transition and Fibroblast-Myofibroblast Transformation in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and incurable chronic interstitial lung disease characterized by excessive fibrosis and impaired lung function. Current treatments, such as pirfenidone and nintedanib, slow disease progression but fail to halt or reverse fibrosis, highlighting the need for novel approaches. Activin A, which belongs to the TGF-β superfamily, is implicated in various fibrosis-related mechanisms, including epithelial-mesenchymal transition (EMT), a process where epithelial cells acquire mesenchymal characteristics, and fibroblast-myofibroblast transformation (FMT), in which fibroblasts differentiate into contractile myofibroblasts. It also promotes inflammatory cytokine release and extracellular matrix buildup. This study aimed to inhibit Activin A activity using synthetic peptides identified through phage display screening. Of the ten peptides isolated, A7, B9, and E10 demonstrated high binding affinity and inhibitory activity. Computational modeling confirmed that these peptides target the receptor-binding domain of Activin A, with peptide E10 exhibiting superior efficacy. Functional assays showed that E10 reduced cell migration, inhibited EMT in A549 cells, and suppressed FMT in fibroblast cultures, even under pro-fibrotic stimulation with TGF-β. These findings underscore the therapeutic potential of targeting Activin A with synthetic peptides, offering a promising avenue for IPF treatment and expanding the arsenal of anti-fibrotic strategies.

Expression and distribution of activin-follistatin-inhibin axis in the urinary bladder

The activin-follistatin-inhibin (AFI) axis plays a crucial role in sexual development and reproduction. Recently it was demonstrated that these proteins are also synthesized by many local tissues and regulate different biological activities, including tissue regeneration and cancer metastasis. However, little is known about the expression profile of the AFI axis in the bladder and its role in bladder function and dysfunction. We have examined the expression profile of 11 AFI family members in the mouse bladder. INHA, INHBA, and follistatin are the major ligand subunits detected among the six examined in the bladder. ACVR1, ACVR1B, and ACVR2B are the major receptor subunits detected among the five examined in the bladder. Immunolocalization studies reveal unique cellular distributions of these ligands and receptors within the bladder. The urothelial-localized ACVR2B/ACVR1B receptor complex suggests a role of activin signaling in urothelial function. The stimulatory activin A is present only in a subset of interstitial cells, separated from the urothelial activin receptor ACVR2B/ACVR1B by a basement membrane containing accumulated inhibitory ligand FST and by a layer of activin-negative myofibroblasts. This spatial information on AFI signal molecules suggests that activin A-positive interstitial cells might regulate urothelial cell function via paracrine signaling through activin A-ACVR2B/ACVR1B interaction. Further analysis of the human bladder confirmed the expression profile of the AFI axis, and revealed significantly upregulated expression of INHBA-ACVR2B in bladder cancer. These data suggest roles for these molecules in the growth and metastasis of bladder cancer, and highlight their potential as diagnostic and prognostic biomarkers.

Kallikrein-8 mediates furin-independent Activin-A precursor processing to stimulate tumor growth in melanoma

Receptor binding of TGF-β and related ligands such as Activin-A requires cleavage of a furin site in their dimeric precursor proteins. Melanoma cells cleave one Activin-A subunit independently of furin and related proprotein convertases, raising questions of how this half-processed intermediate is generated and whether it influences tumor growth. Here, an siRNA library screen for proteases mediating this furin-independent "hemicleavage" identifies kallikrein (Klk)-8. While a KLK8 cleavage site in proActivin-A overlaps with the furin recognition sequence, its exposure is limited and requires prior transient acidification. Therefore, only furin efficiently converts proActivin-A to fully mature form both in tumor cells and in cell-free cleavage assays. Moreover, knockdown of Klk8 in syngeneic melanoma grafts suppresses Activin-A induced tumor growth, demonstrating that cleavage by only furin is not sufficient. Besides elucidating how Activin-A processing is regulated, our findings show that KLK8 holds promise as a target to mitigate Activin-A induced tumor growth.

Roles of thyroid and leptin hormones and their crosstalk in male reproductive functions: an updated review

PURPOSE

This review aims to provide updated information regarding the role of thyroid and leptin hormones and their crosstalk in affecting the male reproductive function in hypothyroid and obesity conditions.

METHOD

A wide literature search was made using online search engines on published articles using keywords including thyroid hormone, hypothyroidism, leptin hormone, hyperleptinemia, obesity, the relationship between thyroid and leptin hormones and male reproduction, and hypothyroidism, obesity, and male reproduction.

RESULTS

All information pertaining thyroid and leptin hormone effects on male reproduction, hypothyroidism, hyperleptinemia, and obesity effect on male fertility as well as the related molecular mechanisms are obtained.

CONCLUSION

Thyroid and leptin hormones individually play a significant role in male reproduction. Alterations of these hormones' levels could adversely affect the male reproductive functions. PI3K/AKT signaling was found to be the major signaling pathway involved in mediating the effect of both hormones on male reproduction. Impaired crosstalk between the two hormones may occur in hypothyroidism with obesity which would contribute towards male reproductive dysfunction.

Structures of TGF-β with betaglycan and signaling receptors reveal mechanisms of complex assembly and signaling

Betaglycan (BG) is a transmembrane co-receptor of the transforming growth factor-β (TGF-β) family of signaling ligands. It is essential for embryonic development, tissue homeostasis and fertility in adults. It functions by enabling binding of the three TGF-β isoforms to their signaling receptors and is additionally required for inhibin A (InhA) activity. Despite its requirement for the functions of TGF-βs and InhA in vivo, structural information explaining BG ligand selectivity and its mechanism of action is lacking. Here, we determine the structure of TGF-β bound both to BG and the signaling receptors, TGFBR1 and TGFBR2. We identify key regions responsible for ligand engagement, which has revealed binding interfaces that differ from those described for the closely related co-receptor of the TGF-β family, endoglin, thus demonstrating remarkable evolutionary adaptation to enable ligand selectivity. Finally, we provide a structural explanation for the hand-off mechanism underlying TGF-β signal potentiation.

17β-estradiol and estrogen receptor alpha protect mouse ovarian follicle development by repressing atresia

Mice administered an inhibin antiserum, equine chorionic gonadotropin (eCG) mixture called CARD HyperOva (OVA)/human chorionic gonadotropin (hCG), ovulate more oocytes than those administered eCG/hCG. In this study, the mechanism by which more oocytes are ovulated was investigated. Apoptotic cells were not observed in ovaries 24 and 48 h after OVA injection, and INHBA expression was absent in the growing follicles with apoptotic cells, whereas granulosa cells in follicles expressing INHBA also expressed estrogen receptor α (ESR1). ESR1 and CYP19A1 expression and 17β-estradiol (E2) in sera significantly increased in OVA-injected mice. Esr1 and Cyp19a1 expression and E2 concentration increased in ovaries cultured with activin A. The ovulation number increased in mice administered diethylstilbestrol. Taken together, these results suggest that ESR1 and E2 are involved in the inhibition of follicular atresia, which increases ovulation and oocyte number. This study may provide valuable information on the molecular mechanisms underlying mouse follicle selection.

Activin E is a new guardian protecting against hepatic steatosis via inhibiting lipolysis in white adipose tissue

Hepatic endoplasmic reticulum (ER) stress is implicated in the development of steatosis and its progression to nonalcoholic steatohepatitis (NASH). The ER in the liver can sustain metabolic function by activating defense mechanisms that delay or prevent the progression of nonalcoholic fatty liver disease (NAFLD). However, the precise mechanisms by which the ER stress response protects against NAFLD remain largely unknown. Recently, activin E has been linked to metabolic diseases such as insulin resistance and NAFLD. However, the physiological conditions and regulatory mechanisms driving hepatic Inhbe expression (which encodes activin E) as well as the metabolic role of activin E in NAFLD require further investigation. Here we found that hepatic Inhbe expression increased under prolonged fasting and ER stress conditions, which was mediated by ATF4, as determined by promoter analysis in a mouse model. Consistently, a positive correlation between INHBE and ATF4 expression levels in relation to NAFLD status was confirmed using public human NAFLD datasets. To investigate the role of activin E in hepatic steatosis, we assessed the fluxes of the lipid metabolism in an Inhbe-knockout mouse model. These mice displayed a lean phenotype but developed severe hepatic steatosis under a high-fat diet. The deficiency of Inhbe resulted in increased lipolysis in adipose tissue, leading to increased fatty acid influx into the liver. Conversely, hepatic overexpression of Inhbe ameliorated hepatic steatosis by suppressing lipolysis in adipose tissue through ALK7-Smad signaling. In conclusion, activin E serves as a regulatory hepatokine that prevents fatty acid influx into the liver, thereby protecting against NAFLD.

INHBA promotes tumor growth and induces resistance to PD-L1 blockade by suppressing IFN-γ signaling

Inhibin beta A (INHBA) and its homodimer activin A have pleiotropic effects on modulation of immune responses and tumor progression, but it remains uncertain whether tumors may release activin A to regulate anti-tumor immunity. In this study we investigated the effects and mechanisms of tumor intrinsic INHBA on carcinogenesis, tumor immunity and PD-L1 blockade. Bioinformatic analysis on the TCGA database revealed that INHBA expression levels were elevated in 33 cancer types, including breast cancer (BRCA) and colon adenocarcinoma (COAD). In addition, survival analysis also corroborated that INHBA expression was negatively correlated with the prognosis of many types of cancer patients. We demonstrated that gain or loss function of Inhba did not alter in vitro growth of colorectal cancer CT26 cells, but had striking impact on mouse tumor models including CT26, MC38, B16 and 4T1 models. By using the TIMER 2.0 tool, we figured out that in most cancer types, Inhba expression in tumors was inversely associated with the infiltration of CD4+ T and CD8+ T cells. In CT26 tumor-bearing mice, overexpression of tumor INHBA eliminated the anti-tumor effect of the PD-L1 antibody atezolizumab, whereas INHBA deficiency enhanced the efficacy of atezolizumab. We revealed that tumor INHBA significantly downregulated the interferon-γ (IFN-γ) signaling pathway. Tumor INHBA overexpression led to lower expression of PD-L1 induced by IFN-γ, resulting in poor responsiveness to anti-PD-L1 treatment. On the other hand, decreased secretion of IFN-γ-stimulated chemokines, including C-X-C motif chemokine 9 (CXCL9) and 10 (CXCL10), impaired the infiltration of effector T cells into the tumor microenvironment (TME). Furthermore, the activin A-specific antibody garetosmab improved anti-tumor immunity and its combination with the anti-PD-L1 antibody atezolizumab showed a superior therapeutic effect to monotherapy with garetosmab or atezolizumab. We demonstrate that INHBA and activin A are involved in anti-tumor immunity by inhibiting the IFN-γ signaling pathway, which can be considered as potential targets to improve the responsive rate of PD-1/PD-L1 blockade.

Associations between accurate measures of adiposity and fitness, blood proteins, and insulin sensitivity among South Asians and Europeans

Objective

South Asians (SAs) may possess a unique predisposition to insulin resistance (IR). We explored this possibility by investigating the relationship between 'gold standard' measures of adiposity, fitness, selected proteomic biomarkers, and insulin sensitivity among a cohort of SAs and Europeans (EURs).

Methods

A total of 46 SAs and 41 EURs completed 'conventional' (lifestyle questionnaires, standard physical exam) as well as 'gold standard' (dual energy X-ray absorptiometry scan, cardiopulmonary exercise test, and insulin suppression test) assessments of adiposity, fitness, and insulin sensitivity. In a subset of 28 SAs and 36 EURs, we also measured the blood-levels of eleven IR-related proteins. We conducted Spearman correlation to identify correlates of steady-state plasma glucose (SSPG) derived from the insulin suppression test, followed by multivariable linear regression analyses of SSPG, adjusting for age, sex and ancestral group.

Results

Sixteen of 30 measures significantly associated with SSPG, including one conventional and eight gold standard measures of adiposity, one conventional and one gold standard measure of fitness, and five proteins. Multivariable regressions revealed that gold standard measures and plasma proteins attenuated ancestral group differences in IR, suggesting their potential utility in assessing IR, especially among SAs.

Conclusion

Ancestral group differences in IR may be explained by accurate measures of adiposity and fitness, with specific proteins possibly serving as useful surrogates for these measures, particularly for SAs.

A Machine Learning Computational Framework Develops a Multiple Programmed Cell Death Index for Improving Clinical Outcomes in Bladder Cancer

Comprehensive action patterns of programmed cell death (PCD) in bladder cancer (BLCA) have not yet been thoroughly investigated. Here, we collected 19 different PCD patterns, including 1911 PCD-related genes, and developed a multiple programmed cell death index (MPCDI) based on a machine learning computational framework. We found that in the TCGA-BLCA training cohort and the independently validated GSE13507 cohort, the patients with high-MPCDI had a worse prognosis, whereas patients with low-MPCDI had a better prognosis. By combining clinical characteristics with the MPCDI, we constructed a nomogram. The C-index demonstrated that the nomogram was significantly more accurate compared to other variables, including MPCDI, age, gender, and clinical stage. The results of the decision curve analysis demonstrated that the nomogram had a better net clinical benefit compared to other clinical variables. Subsequently, we revealed the heterogeneity of BLCA patients, with significant differences in terms of overall immune infiltration abundance, immunotherapeutic response, and drug sensitivity in the two MPCDI groups. Encouragingly, the high-MPCDI patients showed better efficacy for commonly used chemotherapeutic drugs than the low-MPCDI patients, which suggests that MPCDI scores have a guiding role in chemotherapy for BLCA patients. In conclusion, the MPCDI developed and verified in this study is not only an emerging clinical classifier for BLCA patients, but it also serves as a reliable forecaster for both chemotherapy and immunotherapy, which can guide clinical management and clinical decision-making for BLCA patients.

The impact of weight loss on fat-free mass, muscle, bone and hematopoiesis health: Implications for emerging pharmacotherapies aiming at fat reduction and lean mass preservation

Similar to bariatric surgery, incretin receptor agonists have revolutionized the treatment of obesity, achieving up to 15-25 % weight loss in many patients, i.e., at a rate approaching that achieved with bariatric surgery. However, over 25 % of total weight lost from both surgery and pharmacotherapy typically comes from fat-free mass, including skeletal muscle mass, which is often overlooked and can impair metabolic health and increase the risk of subsequent sarcopenic obesity. Loss of muscle and bone as well as anemia can compromise physical function, metabolic rate, and overall health, especially in older adults. The myostatin-activin-follistatin-inhibin system, originally implicated in reproductive function and subsequently muscle regulation, appears to be crucial for muscle and bone maintenance during weight loss. Activins and myostatin promote muscle degradation, while follistatins inhibit their activity in states of negative energy balance, thereby preserving lean mass. Novel compounds in the pipeline, such as Bimagrumab, Trevogrumab, and Garetosmab-which inhibit activin and myostatin signaling-have demonstrated promise in preventing muscle loss while promoting fat loss. Either alone or combined with incretin receptor agonists, these medications may enhance fat loss while preserving or even increasing muscle and bone mass, offering a potential solution for improving body composition and metabolic health during significant weight loss. Since this dual therapeutic approach could help address the challenges of muscle and bone loss during weight loss, well-designed studies are needed to optimize these strategies and assess long-term benefits. For the time being, considerations like advanced age and prefrailty may affect the choice of suitable candidates in clinical practice for current and emerging anti-obesity medications due to the associated risk of sarcopenia.

Expression of the apelin system in the porcine pituitary during the oestrous cycle and early pregnancy and the effect of apelin on LH and FSH secretion

Reproductive success requires considerable energy investment. Research has shown that some adipokines, i.e. the hormones produced in adipose tissue, affect reproductive functions by influencing all structures of the hypothalamic-pituitary-ovarian axis. Apelin is a recently identified member of the adipokine family. To the best of the authors' knowledge, this is the first study to investigate the gene and protein expression of the apelin system (the apelin hormone and the apelin receptor, APJ) in the anterior (AP) and posterior (PP) pituitary lobes of the domestic pig during different phases of the oestrous cycle (days 2 to 3, 10 to 12, 14 to 16, and 17 to 19) and in early pregnancy (days 10 to 11, 12 to 13, 15 to 16, and 27 to 28). It was also assumed that apelin participates in the regulation of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion and influences Akt, MAPK/Erk1/2, and AMPK signalling pathways in the AP during the oestrous cycle. Apelin, APJ mRNAs and proteins were detected in both pituitary lobes. Apelin was identified in gonadotropes, somatotropes, lactotropes, and thyrotropes. The study also revealed that apelin and APJ mRNA/protein levels fluctuate during the oestrous cycle and early gestation. Apelin affects basal, GnRH- and/or insulin-stimulated gonadotropin secretion in some phases of the cycle, as well as the phosphorylation of Akt, MAPK/Erk1/2, and AMPK proteins in AP cells. These findings suggest that apelin may be produced locally in the pituitary and that this gland is receptive to apelin's action. The study also suggest that apelin may influence female reproductive functions by controlling the release of LH and FSH from AP cells, and that it affects Akt, MAPK/Erk1/2, and AMPK signalling pathways.

Activins and Inhibins in Cardiovascular Pathophysiology

Activins and inhibins, members of the transforming growth factor β (TGFβ) superfamily, were initially recognized for their opposing effects on the secretion of follicle-stimulating hormone. Subsequent research has demonstrated their broader biological roles across various tissue types. Primarily, activins and inhibins function through the classical TGFβ SMAD signaling pathway, but studies suggest that they also act through other pathways, with their specific signaling being complex and context-dependent. Recent research has identified significant roles for activins and inhibins in the cardiovascular system. Their actions in other systems and their signaling pathways show strong correlations with the development and progression of cardiovascular diseases, indicating potential broader roles in the cardiovascular system. This review summarizes the progress in research on the biological functions and mechanisms of activins and inhibins and their signaling pathways in cardiovascular diseases, offering new insights for the prevention and treatment of cardiovascular diseases.

Defects of WFS1-mediated peptide hormones secretion contribute to the manifestations of Wolfram syndrome

AIMS

The study aims to investigate whether WFS1 is involved in the regulation of the exportation and secretion of other peptide hormones, as well as to elucidate the precise molecular mechanisms underlying WS caused by pathogenic mutations in the WFS1 gene.

MATERIALS AND METHODS

The plasma proteome from the WS patients (n = 2, male) and WFS1-deficient mice (n = 5, male) were analyzed using liquid-chromatography tandem mass spectrometry (LC-MS/MS), while age- and gender-matched healthy individuals and wildtype (WT) mice serve as controls. WFS1-deficient mice were intraperitoneally injected with IGF1 starting from 4 weeks of age. Body weight was monitored every 2 days, fasting blood glucose and glucose tolerance test were performed on the day 30 and day 40 after injection of IGF1, respectively. BiFC (bimolecular fluorescence complementation) and Co-immunoprecipitation (IP) were used to analyze the interaction between WFS1 and peptide hormones. Confocal microscopy was employed to analyze the colocalization of IGF1 with ER and Golgi.

KEY FINDINGS

Peptide hormones are deficient in both the plasma of WS patients and WFS1-deficient mice. WFS1 binds to and mediates the secretion of these peptide hormones, suggesting that WFS1 serves as a general COPII vesicular receptor for sorting peptide hormones. Interestingly, the WFS1 pathogenic mutations significantly disrupt its interaction with these peptide hormones. Furthermore, intraperitoneal administration of IGF1 partially attenuates high blood glucose levels in WFS1-deficient male mice.

SIGNIFICANCE

This study suggests that WS is characterized by defective peptide hormone secretion and proposes administration of these deficient peptide hormones as a promising treatment regimen for WS.

Investigating the potential effect of Holothuria scabra extract on osteogenic differentiation in preosteoblast MC3T3-E1 cells

The present medical treatments of osteoporosis come with adverse effects. It leads to the exploration of natural products as safer alternative medical prevention and treatment. The sea cucumber, Holothuria scabra, has commercial significance in Asian countries with rising awareness of its properties as a functional food. This study aims to investigate the effects of the inner wall (IW) extract isolated from H. scabra on extracellular matrix maturation, mineralization, and osteogenic signaling pathways on MC3T3-E1 preosteoblasts. The IW showed the expression of several growth factors. Molecular docking revealed that H. scabra BMP2/4 binds specifically to mammal BMP2 type I receptor (BMPR-IA). After osteogenic induction, the viability of cells treated with IW extract was assessed and designated with treatment of 0.1, 0.5, 1, and 5 µg/ml of IW extract for 21 consecutive days. On days 14 and 21, treatments with IW extract at 1 and 5 µg/ml showed increased alkaline phosphatase (ALP) activity and calcium deposit levels in a dose-dependent manner compared to the control group. Moreover, the transcriptomic analysis of total RNA of cells treated with 5 µg/ml of IW extract exhibited upregulation of TGF-β, PI3K/Akt, MAPK, Wnt and PTH signaling pathways at days 14. This study suggests that IW extract from H. scabra exhibits the potential to enhance osteogenic differentiation and mineralization of MC3T3-E1 preosteoblasts through TGF-β, PI3K/Akt, MAPK, Wnt and PTH signaling pathways. Further investigation into the molecular mechanisms underlying the effect of IW extract on osteogenesis is crucial to support its application as a naturally derived supplement for prevention or treatment of osteoporosis.

Stepwise release of Activin-A from its inhibitory prodomain is modulated by cysteines and requires furin coexpression to promote melanoma growth

The Activin-A precursor dimer can be cleaved by furin, but how this proteolytic maturation is regulated in vivo and how it facilitates access to signaling receptors is unclear. Here, analysis in a syngeneic melanoma grafting model shows that without furin coexpression, Activin-A failed to accelerate tumor growth, correlating with failure of one or both subunits to undergo cleavage in signal-sending cells, even though compensatory processing by host cells nonetheless sustained elevated circulating Activin-A levels. In reporter assays, furin-independent cleavage of one subunit enabled juxtacrine Activin-A signaling, whereas completion of proteolytic maturation by coexpressed furin or by recipient cells stimulated contact-independent activity, crosstalk with BMP receptors, and signal inhibition by follistatin. Mechanistically, Activin-A processing was modulated by allosteric disulfide bonds flanking the furin site. Disruption of these disulfide linkages with the prodomain enabled Activin-A binding to cognate type II receptors independently of proteolytic maturation. Stepwise proteolytic maturation is a novel mechanism to control Activin-A protein interactions and signaling.

Oxidative Stress-induced Hormonal Disruption in Male Reproduction

Research into the impacts of oxidative stress (OS), and hormonal balance on reproductive potential has increased over the last 40 years possibly due to rising male infertility. Decreased antioxidant levels and increased OS in tissues result from hormonal imbalance, which in turn leads to male infertility. Increased reactive oxygen species (ROS) generation in seminal plasma has been linked to many lifestyle factors such as alcohol and tobacco use, toxicant exposure, obesity, varicocele, stress, and aging. This article provides an overview of the crosslink between OS and gonadal hormone disruption, as well as a potential mode of action in male infertility. Disrupting the equilibrium between ROS generation and the antioxidant defense mechanism in the male reproductive system may affect key hormonal regulators of male reproductive activities. Unchecked ROS production may cause direct injury on reproductive tissues or could disrupt normal regulatory mechanisms of the hypothalamic-pituitary-gonadal (HPG) axis and its interaction with other endocrine axes, both of which have negative effects on male reproductive health and can lead to male infertility.

Single cell RNA sequencing of human eosinophils from nasal polyps reveals eosinophil heterogeneity in chronic rhinosinusitis tissue

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by type 2 inflammation in the United States, but the actual roles that eosinophils play in CRSwNP remain largely unclear.

OBJECTIVE

To reveal the roles and heterogeneity of eosinophils in nasal polyp (NP) tissue, we performed single cell RNA sequencing (scRNA-Seq) analysis of NP tissue.

METHODS

Sinonasal tissues (NP and control sinus tissue) and patient matched peripheral blood (PB) samples were obtained from 5 control patients and 5 patients with CRSwNP. Eosinophils were enriched before processing for scRNA-Seq. The gene expression profiles in eosinophils were determined by microwell-based scRNA-Seq technology (BD Rhapsody platform). We predicted the overall function of NP eosinophils by Gene Ontology (geneontology.org) enrichment and pathway analyses and confirmed expression of selected genes by flow cytometry.

RESULTS

After filtering out contaminating cells, we detected 5,542 eosinophils from control PB, 3,883 eosinophils from CRSwNP PB, 101 eosinophils from control sinus tissues (not included in further analyses), and 9,727 eosinophils from NPs by scRNA-Seq. We found that 204 genes were downregulated and 354 genes upregulated in NP eosinophils compared to all PB eosinophils (>1.5-fold, Padj < .05). Upregulated genes in NP eosinophils were associated with activation, cytokine-mediated signaling, growth factor activity, NF-κB signaling, and antiapoptotic molecules. NP eosinophils displayed 4 clusters revealing potential heterogeneity of eosinophils in NP tissue.

CONCLUSIONS

Elevated eosinophils in NP tissue appear to exist in several subtypes that may play important pathogenic roles in CRSwNP, in part by controlling inflammation and hyperproliferation of other cells.

Relative Energy Deficiency in Sport (REDs): Endocrine Manifestations, Pathophysiology and Treatments

Research on lean, energy-deficient athletic and military cohorts has broadened the concept of the Female Athlete Triad into the Relative Energy Deficiency in Sport (REDs) syndrome. REDs represents a spectrum of abnormalities induced by low energy availability (LEA), which serves as the underlying cause of all symptoms described within the REDs concept, affecting exercising populations of either biological sex. Both short- and long-term LEA, in conjunction with other moderating factors, may produce a multitude of maladaptive changes that impair various physiological systems and adversely affect health, well-being, and sport performance. Consequently, the comprehensive definition of REDs encompasses a broad spectrum of physiological sequelae and adverse clinical outcomes related to LEA, such as neuroendocrine, bone, immune, and hematological effects, ultimately resulting in compromised health and performance. In this review, we discuss the pathophysiology of REDs and associated disorders. We briefly examine current treatment recommendations for REDs, primarily focusing on nonpharmacological, behavioral, and lifestyle modifications that target its underlying cause-energy deficit. We also discuss treatment approaches aimed at managing symptoms, such as menstrual dysfunction and bone stress injuries, and explore potential novel treatments that target the underlying physiology, emphasizing the roles of leptin and the activin-follistatin-inhibin axis, the roles of which remain to be fully elucidated, in the pathophysiology and management of REDs. In the near future, novel therapies leveraging our emerging understanding of molecules and physiological axes underlying energy availability or lack thereof may restore LEA-related abnormalities, thus preventing and/or treating REDs-related health complications, such as stress fractures, and improving performance.

Associations between accurate measures of adiposity and fitness, blood proteins, and insulin sensitivity among South Asians and Europeans

Objective

South Asians (SAs) may possess a unique predisposition to insulin resistance (IR). We explored this possibility by investigating the relationship between 'gold standard' measures of adiposity, fitness, selected proteomic biomarkers, and insulin sensitivity among a cohort of SAs and Europeans (EURs).

Methods

A total of 46 SAs and 41 EURs completed 'conventional' (lifestyle questionnaires, standard physical exam) as well as 'gold standard' (dual energy X-ray absorptiometry scan, cardiopulmonary exercise test, and insulin suppression test) assessments of adiposity, fitness, and insulin sensitivity. In a subset of 28 SAs and 36 EURs, we also measured the blood-levels of eleven IR-related proteins. We conducted Spearman correlation to identify correlates of steady-state plasma glucose (SSPG) derived from the insulin suppression test, followed by multivariable linear regression analyses of SSPG, adjusting for age, sex and ancestral group.

Results

Sixteen of 30 measures significantly associated with SSPG, including one conventional and eight gold standard measures of adiposity, one conventional and one gold standard measure of fitness, and five proteins. Multivariable regressions revealed that gold standard measures and plasma proteins attenuated ancestral group differences in IR, suggesting their potential utility in assessing IR, especially among SAs.

Conclusion

Ancestral group differences in IR may be explained by accurate measures of adiposity and fitness, with specific proteins possibly serving as useful surrogates for these measures, particularly for SAs.

Association and causality between diabetes and activin A: a two-sample Mendelian randomization study

Activin A, a cytokine belonging to the transforming growth factor-beta (TGF-β) superfamily, mediates a multifunctional signaling pathway that is essential for embryonic development, cell differentiation, metabolic regulation, and physiological equilibrium. Biomedical research using diabetes-based model organisms and cellular cultures reports evidence of different activin A levels between diabetic and control groups. Activin A is highly conserved across species and universally expressed among disparate tissues. A systematic review of published literatures on human populations reveals association of plasma activin A levels with diabetic patients in some (7) but not in others (5) of the studies. With summarized data from publicly available genome-wide association studies (GWASs), a two-sample Mendelian randomization (TSMR) analysis is conducted on the causality between the exposure and the outcome. Wald ratio estimates from single instruments are predominantly non-significant. In contrast to positive controls between diabetes and plasma cholesterol levels, inverse-variance-weighted (IVW), Egger, weighted median, and weighted mode MR methods all lead to no observed causal link between diabetes (type 1 and type 2) and plasma activin A levels. Unavailability of strong instruments prevents the reversal MR analysis of activin A on diabetes. In summary, further research is needed to confirm or deny the potential association between diabetes and plasma activin A, and to elucidate the temporal incidence of these traits in human populations. At this stage, no causality has been found between diabetes and plasma activin A based on TSMR analysis.

Unraveling the interplay: exploring signaling pathways in pancreatic cancer in the context of pancreatic embryogenesis

Pancreatic cancer continues to be a deadly disease because of its delayed diagnosis and aggressive tumor biology. Oncogenes and risk factors are being reported to influence the signaling pathways involved in pancreatic embryogenesis leading to pancreatic cancer genesis. Although studies using rodent models have yielded insightful information, the scarcity of human pancreatic tissue has made it difficult to comprehend how the human pancreas develops. Transcription factors like IPF1/PDX1, HLXB9, PBX1, MEIS, Islet-1, and signaling pathways, including Hedgehog, TGF-β, and Notch, are directing pancreatic organogenesis. Any derangements in the above pathways may lead to pancreatic cancer. TP53: and CDKN2A are tumor suppressor genes, and the mutations in TP53 and somatic loss of CDKN2A are the drivers of pancreatic cancer. This review clarifies the complex signaling mechanism involved in pancreatic cancer, the same signaling pathways in pancreas development, the current therapeutic approach targeting signaling molecules, and the mechanism of action of risk factors in promoting pancreatic cancer.

KIT in oocytes: a key factor for oocyte survival and reproductive lifespan

BACKGROUND

The KITL-KIT interaction is known as an important initiator in oocyte activation through the downstream pathway of PI3K-AKT-FOXO3 signalling. Previous studies utilising germ cell-specific Kit mutant knockin and kinase domain knockout models with Vasa-Cre suggested the crucial role of KIT in oocyte activation at the primordial follicle stage.

METHODS

We utilised mice with complete postnatal deletion of KIT expression in oocytes via Gdf9-iCre and conducted analyses on ovarian follicle development, specific markers, hormone assays, and fertility outcomes.

FINDINGS

Our findings reveal contrasting phenotypes compared to previous mouse models with prenatal deletion of Kit. Specifically, postnatal deletion of Kit exhibit no defects in germ cell nest breakdown, follicle activation, and folliculogenesis during development. Remarkably, upon reaching full maturity, mice with postnatal deletion of Kit experience a complete loss of ovarian reserve, growing follicles, and ovarian function. Furthermore, mice display smaller ovarian size and weight, delayed folliculogenesis, and phenotypes indicative of primary ovarian insufficiency (POI), including elevated serum levels of FSH, reduced AMH, and absence of ovarian follicles, ultimately resulting in infertility. Additionally, the ovaries exhibit randomly distributed expression of granulosa and theca cell markers such as Inhibin α, ACVR2B, and LHR. Notably, there is the uncontrolled expression of p-SMAD3 and Ki67 throughout the ovarian sections, along with the widespread presence of luteinised stroma cells and cleaved Caspase-3-positive dying cells.

INTERPRETATION

These genetic studies underscore the indispensable role of KIT in oocytes for maintaining the survival of ovarian follicles and ensuring the reproductive lifespan.

FUNDING

This work was supported by National Institutes of Health grant R01HD096042 and startup funds from UNMC (S.Y.K.).

Structures of TGF-β with betaglycan and the signaling receptors reveal the mechanism whereby betaglycan potentiates receptor complex assembly and signaling

Betaglycan (BG) is a transmembrane co-receptor of the transforming growth factor-β (TGF-β) family of signaling ligands. It is essential for embryonic development and tissue homeostasis and fertility in adults. It functions by enabling binding of the three TGF-β isoforms to their signaling receptors and is additionally required for inhibin A (InhA) activity. Despite its requirement for the functions of TGF-βs and InhA in vivo, structural information explaining BG ligand selectivity and its mechanism of action is lacking. Here, we determine the structure of TGF-β bound both to BG and the signaling receptors, TGFBR1 and TGFBR2. We identify key regions responsible for ligand engagement, which has revealed novel binding interfaces that differ from those described for the closely related co-receptor of the TGF-β family, endoglin, thus demonstrating remarkable evolutionary adaptation to enable ligand selectivity. Finally, we provide a structural explanation for the hand-off mechanism underlying TGF-β signal potentiation.

TGFβ signalling: a nexus between inflammation, placental health and preeclampsia throughout pregnancy

BACKGROUND

The placenta is a unique and pivotal organ in reproduction, controlling crucial growth and cell differentiation processes that ensure a successful pregnancy. Placental development is a tightly regulated and dynamic process, in which the transforming growth factor beta (TGFβ) superfamily plays a central role. This family of pleiotropic growth factors is heavily involved in regulating various aspects of reproductive biology, particularly in trophoblast differentiation during the first trimester of pregnancy. TGFβ signalling precisely regulates trophoblast invasion and the cell transition from cytotrophoblasts to extravillous trophoblasts, which is an epithelial-to-mesenchymal transition-like process. Later in pregnancy, TGFβ signalling ensures proper vascularization and angiogenesis in placental endothelial cells. Beyond its role in trophoblasts and endothelial cells, TGFβ signalling contributes to the polarization and function of placental and decidual macrophages by promoting maternal tolerance of the semi-allogeneic foetus. Disturbances in early placental development have been associated with several pregnancy complications, including preeclampsia (PE) which is one of the severe complications. Emerging evidence suggests that TGFβ is involved in the pathogenesis of PE, thereby offering a potential target for intervention in the human placenta.

OBJECTIVE AND RATIONALE

This comprehensive review aims to explore and elucidate the roles of the major members of the TGFβ superfamily, including TGFβs, bone morphogenetic proteins (BMPs), activins, inhibins, nodals, and growth differentiation factors (GDFs), in the context of placental development and function. The review focusses on their interactions within the major cell types of the placenta, namely trophoblasts, endothelial cells, and immune cells, in both normal pregnancies and pregnancies complicated by PE throughout pregnancy.

SEARCH METHODS

A literature search was carried out using PubMed and Google Scholar, searching terms: 'TGF signalling preeclampsia', 'pregnancy TGF signalling', 'preeclampsia tgfβ', 'preeclampsia bmp', 'preeclampsia gdf', 'preeclampsia activin', 'endoglin preeclampsia', 'endoglin pregnancy', 'tgfβ signalling pregnancy', 'bmp signalling pregnancy', 'gdf signalling pregnancy', 'activin signalling pregnancy', 'Hofbauer cell tgfβ signalling', 'placental macrophages tgfβ', 'endothelial cells tgfβ', 'endothelium tgfβ signalling', 'trophoblast invasion tgfβ signalling', 'trophoblast invasion Smad', 'trophoblast invasion bmp', 'trophoblast invasion tgfβ', 'tgfβ preeclampsia', 'tgfβ placental development', 'TGFβ placental function', 'endothelial dysfunction preeclampsia tgfβ signalling', 'vascular remodelling placenta TGFβ', 'inflammation pregnancy tgfβ', 'immune response pregnancy tgfβ', 'immune tolerance pregnancy tgfβ', 'TGFβ pregnancy NK cells', 'bmp pregnancy NK cells', 'bmp pregnancy tregs', 'tgfβ pregnancy tregs', 'TGFβ placenta NK cells', 'TGFβ placenta tregs', 'NK cells preeclampsia', 'Tregs preeclampsia'. Only articles published in English until 2023 were used.

OUTCOMES

A comprehensive understanding of TGFβ signalling and its role in regulating interconnected cell functions of the main placental cell types provides valuable insights into the processes essential for successful placental development and growth of the foetus during pregnancy. By orchestrating trophoblast invasion, vascularization, immune tolerance, and tissue remodelling, TGFβ ligands contribute to the proper functioning of a healthy maternal-foetal interface. However, dysregulation of TGFβ signalling has been implicated in the pathogenesis of PE, where the shallow trophoblast invasion, defective vascular remodelling, decreased uteroplacental perfusion, and endothelial cell and immune dysfunction observed in PE, are all affected by an altered TGFβ signalling.

WIDER IMPLICATIONS

The dysregulation of TGFβ signalling in PE has important implications for research and clinical practice. Further investigation is required to understand the underlying mechanisms, including the role of different ligands and their regulation under pathophysiological conditions, in order to discover new therapeutic targets. Distinguishing between clinically manifested subtypes of PE and studying TGFβ signalling in different placental cell types holistically is an important first step. To put this knowledge into practice, pre-clinical animal models combined with new technologies are needed. This may also lead to improved human research models and identify potential therapeutic targets, ultimately improving outcomes for affected pregnancies and reducing the burden of PE.

Spemann-Mangold organizer and mesoderm induction

The discovery of the Spemann-Mangold organizer strongly influenced subsequent research on embryonic induction, with research aiming to elucidate the molecular characteristics of organizer activity being currently underway. Herein, we review the history of research on embryonic induction, and describe how the mechanisms of induction phenomena and developmental processes have been investigated. Classical experiments investigating the differentiation capacity and inductive activity of various embryonic regions were conducted by many researchers, and important theories of region-specific induction and the concept for chain of induction were proposed. The transition from experimental embryology to developmental biology has enabled us to understand the mechanisms of embryonic induction at the molecular level. Consequently, many inducing substances and molecules such as transcriptional factors and peptide growth factors involved in the organizer formation were identified. One of peptide growth factors, activin, acts as a mesoderm- and endoderm-inducing substance. Activin induces several tissues and organs from the undifferentiated cell mass of amphibian embryos in a concentration-dependent manner. We review the extent to which we can control in vitro organogenesis from undifferentiated cells, and discuss the application to stem cell-based regenerative medicine based on insights gained from animal experiments, such as in amphibians.

Inhibition of activin receptor 2 signalling ameliorates metabolic dysfunction-associated steatotic liver disease in western diet/L-NAME induced cardiometabolic disease

OBJECTIVE

Blockade of activin 2 receptor (ACVR2) signaling has been shown to improve insulin sensitivity and aid in weight loss. Inhibition of ACVR2 signaling restores cardiac function in multiple heart failure models. However, its potential in the treatment of obesity-related cardiometabolic disease remains unknown. Here, we investigated targeting ACVR2 signaling in cardiometabolic disease manifested with metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

Mice were fed a high-fat, high-sugar diet combined with the administration of nitric oxide synthase inhibitor L-NAME in drinking water, which causes hypertensive stress. For the last eight weeks, the mice were treated with the soluble ACVR2B decoy receptor (sACVR2B-Fc).

RESULTS

sACVR2B-Fc protected against the development of comorbidities associated with cardiometabolic disease. This was most pronounced in the liver where ACVR2 blockade attenuated the development of MASLD including cessation of pro-fibrotic activation. It also significantly reduced total plasma cholesterol levels, impeded brown adipose tissue whitening, and improved cardiac diastolic function. In vitro, ACVR2 ligands activin A, activin B and GDF11 induced profibrotic signaling and the proliferation of human cardiac fibroblasts.

CONCLUSIONS

Blockade of ACVR2B exerts broad beneficial effects for therapy of cardiometabolic disease. By reducing obesity, ameliorating cardiovascular deterioration and restraining MASLD, blockade of ACVR2B signaling proves a potential target in MASLD and its comorbidities.

Maternal TGF-β ligand Panda breaks the radial symmetry of the sea urchin embryo by antagonizing the Nodal type II receptor ACVRII

In the highly regulative embryo of the sea urchin Paracentrotus lividus, establishment of the dorsal-ventral (D/V) axis critically depends on the zygotic expression of the TGF-β nodal in the ventral ectoderm. nodal expression is first induced ubiquitously in the 32-cell embryo and becomes progressively restricted to the presumptive ventral ectoderm by the early blastula stage. This early spatial restriction of nodal expression is independent of Lefty, and instead relies on the activity of Panda, a maternally expressed TGF-β ligand related to Lefty and Inhibins, which is required maternally for D/V axis specification. However, the mechanism by which Panda restricts the early nodal expression has remained enigmatic and it is not known if Panda works like a BMP ligand by opposing Nodal and antagonizing Smad2/3 signaling, or if it works like Lefty by sequestering an essential component of the Nodal signaling pathway. In this study, we report that Panda functions as an antagonist of the TGF-β type II receptor ACVRII (Activin receptor type II), which is the only type II receptor for Nodal signaling in the sea urchin and is also a type II receptor for BMP ligands. Inhibiting translation of acvrII mRNA disrupted D/V patterning across all 3 germ layers and caused acvrII morphants to develop with a typical Nodal loss-of-function phenotype. In contrast, embryos overexpressing acvrII displayed strong ectopic Smad1/5/8 signaling at blastula stages and developed as dorsalized larvae, a phenotype very similar to that caused by over activation of BMP signaling. Remarkably, embryos co-injected with acvrII mRNA and panda mRNA did not show ectopic Smad1/5/8 signaling and developed with a largely normal dorsal-ventral polarity. Furthermore, using an axis induction assay, we found that Panda blocks the ability of ACVRII to orient the D/V axis when overexpressed locally. Using co-immunoprecipitation, we showed that Panda physically interacts with ACVRII, as well as with the Nodal co-receptor Cripto, and with TBR3 (Betaglycan), which is a non-signaling receptor for Inhibins in mammals. At the molecular level, we have traced back the antagonistic activity of Panda to the presence of a single proline residue, conserved with all the Lefty factors, in the ACVRII binding motif of Panda, instead of a serine as in most of TGF-β ligands. Conversion of this proline to a serine converted Panda from an antagonist that opposed Nodal signaling and promoted dorsalization to an agonist that promoted Nodal signaling and triggered ventralization when overexpressed. Finally, using phylogenomics, we analyzed the emergence of the agonist and antagonist form of Panda in the course of evolution. Our data are consistent with the idea that the presence of a serine at that position, like in most TGF-β, was the ancestral condition and that the initial function of Panda was possibly in promoting and not in antagonizing Nodal signaling. These results highlight the existence of key functional and structural elements conserved between Panda and Lefty, allow to draw an intriguing parallel between sea urchin Panda and mammalian Inhibin α and raise the unexpected possibility that the original function of Panda may have been in activation of the Nodal pathway rather than in its inhibition.

Single-cell transcriptomic profiling of the neonatal oviduct and uterus reveals new insights into upper Müllerian duct regionalization

The upper Müllerian duct (MD) is patterned and specified into two morphologically and functionally distinct organs, the oviduct and uterus. It is known that this regionalization process is instructed by inductive signals from the adjacent mesenchyme. However, the interaction landscape between epithelium and mesenchyme during upper MD development remains largely unknown. Here, we performed single-cell transcriptomic profiling of mouse neonatal oviducts and uteri at the initiation of MD epithelial differentiation (postnatal day 3). We identified major cell types including epithelium, mesenchyme, pericytes, mesothelium, endothelium, and immune cells in both organs with established markers. Moreover, we uncovered region-specific epithelial and mesenchymal subpopulations and then deduced region-specific ligand-receptor pairs mediating mesenchymal-epithelial interactions along the craniocaudal axis. Unexpectedly, we discovered a mesenchymal subpopulation marked by neurofilaments with specific localizations at the mesometrial pole of both the neonatal oviduct and uterus. Lastly, we analyzed and revealed organ-specific signature genes of pericytes and mesothelial cells. Taken together, our study enriches our knowledge of upper MD development, and provides a manageable list of potential genes, pathways, and region-specific cell subtypes for future functional studies.

Gonadotropin elevation is ootoxic to ovulatory oocytes and inhibits oocyte maturation, and activin decoy receptor ActRIIB:Fc therapeutically restores maturation

BACKGROUND

Elevated FSH often occurs in women of advanced maternal age (AMA, age ≥ 35) and in infertility patients undergoing controlled ovarian stimulation (COS). There is controversy on whether high endogenous FSH contributes to infertility and whether high exogenous FSH adversely impacts patient pregnancy rates.

METHODS

The senescence-accelerated mouse-prone-8 (SAMP8) model of female reproductive aging was employed to assess the separate impacts of age and high FSH activity on the percentages (%) of viable and mature ovulated oocytes recovered after gonadotropin treatment. Young and midlife mice were treated with the FSH analog equine chorionic gonadotropin (eCG) to model both endogenous FSH elevation and exogenous FSH elevation. Previously we showed the activin inhibitor ActRIIB:Fc increases oocyte quality by preventing chromosome and spindle misalignments. Therefore, ActRIIB:Fc treatment was performed in an effort to increase % oocyte viability and % oocyte maturation.

RESULTS

The high FSH activity of eCG is ootoxic to ovulatory oocytes, with greater decreases in % viable oocytes in midlife than young mice. High FSH activity of eCG potently inhibits oocyte maturation, decreasing the % of mature oocytes to similar degrees in young and midlife mice. ActRIIB:Fc treatment does not prevent eCG ootoxicity, but it restores most oocyte maturation impeded by eCG.

CONCLUSIONS

FSH ootoxicity to ovulatory oocytes and FSH maturation inhibition pose a paradox given the well-known pro-growth and pro-maturation activities of FSH in the earlier stages of oocyte growth. We propose the FOOT Hypothesis ("FSH OoToxicity Hypothesis), that FSH ootoxicity to ovulatory oocytes comprises a new driver of infertility and low pregnancy success rates in DOR women attempting spontaneous pregnancy and in COS/IUI patients, especially AMA women. We speculate that endogenous FSH elevation also contributes to reduced fecundity in these DOR and COS/IUI patients. Restoration of oocyte maturation by ActRIB:Fc suggests that activin suppresses oocyte maturation in vivo. This contrasts with prior studies showing activin A promotes oocyte maturation in vitro. Improved oocyte maturation with agents that decrease endogenous activin activity with high specificity may have therapeutic benefit for COS/IVF patients, COS/IUI patients, and DOR patients attempting spontaneous pregnancies.

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.

Activin E is a transforming growth factor β ligand that signals specifically through activin receptor-like kinase 7

Activins are one of the three distinct subclasses within the greater Transforming growth factor β (TGFβ) superfamily. First discovered for their critical roles in reproductive biology, activins have since been shown to alter cellular differentiation and proliferation. At present, members of the activin subclass include activin A (ActA), ActB, ActC, ActE, and the more distant members myostatin and GDF11. While the biological roles and signaling mechanisms of most activins class members have been well-studied, the signaling potential of ActE has remained largely unknown. Here, we characterized the signaling capacity of homodimeric ActE. Molecular modeling of the ligand:receptor complexes showed that ActC and ActE shared high similarity in both the type I and type II receptor binding epitopes. ActE signaled specifically through ALK7, utilized the canonical activin type II receptors, ActRIIA and ActRIIB, and was resistant to the extracellular antagonists follistatin and WFIKKN. In mature murine adipocytes, ActE invoked a SMAD2/3 response via ALK7, like ActC. Collectively, our results establish ActE as a specific signaling ligand which activates the type I receptor, ALK7.

Inhibin A contributes to the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated m6A modification

BACKGROUND

Inhibin A and N6-methyladenosine methylation modifications participate in oral squamous cell carcinoma development. However, the N6-methyladenosine modification of Inhibin A in oral squamous cell carcinoma has not been revealed. This study reveals a key gene "Inhibin A" that may affect the tumorigenesis of oral squamous cell carcinoma and its molecular mechanisms on N6-methyladenosine methyltransferase KIAA1429-mediated N6-methyladenosine methylation modification.

METHODS

Bioinformatics analysis and quantitative real-time polymerase chain reaction identified the potential regulatory genes in oral squamous cell carcinoma. We examined the changes in the proliferation (Cell Counting Kit-8 assay), migration (transwell migration assay), and invasion (transwell invasion assays) of oral squamous cell carcinoma cells. We performed a xenograft tumor experiment to validate the role of Inhibin A in oral squamous cell carcinoma in vivo. The interactions between Inhibin A and KIAA1429 were analyzed using bioinformatics, methylated RNA immunoprecipitation-qPCR, quantitative real-time polymerase chain reaction, and Western blotting experiments.

RESULTS

Inhibin A had the highest expression in patients with oral squamous cell carcinoma. Inhibin A silencing impaired the ability of oral squamous cell carcinoma cells to proliferate, migrate, and invade, as well as limited the tumorous growth of oral squamous cell carcinoma cells in vivo. Bioinformatics analysis showed that Inhibin A expression positively interacted with KIAA1429 expression in The Cancer Genome Atlas database. The levels were also upregulated in our clinical samples. Furthermore, KIAA1429 silencing repressed the N6-methyladenosine level of Inhibin A in oral squamous cell carcinoma.

CONCLUSIONS

Inhibin A promotes the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated N6-methyladenosine modification. This study adds to our current knowledge of the molecular mechanisms underlying oral squamous cell carcinoma malignancy.

Stable and Oscillatory Hypoxia Differentially Regulate Invasibility of Breast Cancer Associated Fibroblasts

As local regions in the tumor outstrip their oxygen supply, hypoxia can develop, affecting not only the cancer cells, but also other cells in the microenvironment, including cancer associated fibroblasts (CAFs). Hypoxia is also not necessarily stable over time, and can fluctuate or oscillate. Hypoxia Inducible Factor-1 is the master regulator of cellular response to hypoxia, and can also exhibit oscillations in its activity. To understand how stable, and fluctuating hypoxia influence breast CAFs, we measured changes in gene expression in CAFs in normoxia, hypoxia, and oscillatory hypoxia, as well as measured change in their capacity to resist, or assist breast cancer invasion. We show that hypoxia has a profound effect on breast CAFs causing activation of key pathways associated with fibroblast activation, but reduce myofibroblast activation and traction force generation. We also found that oscillatory hypoxia, while expectedly resulted in a "sub-hypoxic" response in gene expression, it resulted in specific activation of pathways associated with actin polymerization and actomyosin maturation. Using traction force microscopy, and a nanopatterned stromal invasion assay, we show that oscillatory hypoxia increases contractile force generation vs stable hypoxia, and increases heterogeneity in force generation response, while also additively enhancing invasibility of CAFs to MDA-MB-231 invasion. Our data show that stable and unstable hypoxia can regulate many mechnobiological characteristics of CAFs, and can contribute to transformation of CAFs to assist cancer dissemination and onset of metastasis.

Direct male development in chromosomally ZZ zebrafish

The genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish (Danio rerio), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males. To understand mechanisms of gonad development in NA zebrafish, we studied histology and single cell transcriptomics in developing ZZ and ZW fish. ZW fish developed oocytes by 22 days post-fertilization (dpf) but ZZ fish directly formed testes, avoiding a juvenile ovary phase. Gonads of some ZW and WW fish, however, developed oocytes that died as the gonad became a testis, mimicking AB fish, suggesting that the gynogenetically derived AB strain is chromosomally WW. Single-cell RNA-seq of 19dpf gonads showed similar cell types in ZZ and ZW fish, including germ cells, precursors of gonadal support cells, steroidogenic cells, interstitial/stromal cells, and immune cells, consistent with a bipotential juvenile gonad. In contrast, scRNA-seq of 30dpf gonads revealed that cells in ZZ gonads had transcriptomes characteristic of testicular Sertoli, Leydig, and germ cells while ZW gonads had granulosa cells, theca cells, and developing oocytes. Hematopoietic and vascular cells were similar in both sex genotypes. These results show that juvenile NA zebrafish initially develop a bipotential gonad; that a factor on the NA W chromosome, or fewer than two Z chromosomes, is essential to initiate oocyte development; and without the W factor, or with two Z doses, NA gonads develop directly into testes without passing through the juvenile ovary stage. Sex determination in AB and TU strains mimics NA ZW and WW zebrafish, suggesting loss of the Z chromosome during domestication. Genetic analysis of the NA strain will facilitate our understanding of the evolution of sex determination mechanisms.

The TGF-β superfamily as potential therapeutic targets in pancreatic cancer

The transforming growth factor (TGF)-β superfamily has important physiologic roles and is dysregulated in many pathologic processes, including pancreatic cancer. Pancreatic cancer is one of the most lethal cancer diagnoses, and current therapies are largely ineffective due to tumor resistance and late-stage diagnosis with poor prognosis. Recent efforts are focused on the potential of immunotherapies in improving therapeutic results for patients with pancreatic cancer, among which TGF-β has been identified as a promising target. This review focuses on the role of TGF-β in the diseased pancreas and pancreatic cancer. It also aims to summarize the current status of therapies targeting the TGF-β superfamily and postulate potential future directions in targeting the TGF-β signaling pathways.

Bariatric surgery, through beneficial effects on underlying mechanisms, improves cardiorenal and liver metabolic risk over an average of ten years of observation: A longitudinal and a case-control study

BACKGROUND

Bariatric surgery has long-term beneficial effects on body weight and metabolic status, but there is an apparent lack of comprehensive cardiometabolic, renal, liver, and metabolomic/lipidomic panels, whereas the underlying mechanisms driving the observed postoperative ameliorations are still poorly investigated. We aimed to study the long-term effects of bariatric surgery on metabolic profile, cardiorenal and liver outcomes in association with underlying postoperative gut hormone adaptations.

METHODS

28 individuals who underwent bariatric surgery [17 sleeve gastrectomy (SG), 11 Roux-en-Y gastric bypass (RYGB)] were followed up 3, 6 and 12 and at 10 years following surgery. Participants at 10 years were cross-sectionally compared with an age-, sex- and adiposity-matched group of non-operated individuals (n = 9) and an age-matched pilot group of normal-weight individuals (n = 4).

RESULTS

There were durable effects of surgery on body weight and composition, with an increase of lean mass percentage persisting despite some weight regain 10 years postoperatively. The improvements in metabolic and lipoprotein profiles, cardiometabolic risk markers, echocardiographic and cardiorenal outcomes persisted over the ten-year observation period. The robust improvements in insulin resistance, adipokines, activin/follistatin components and postprandial gastrointestinal peptide levels persisted 10 years postoperatively. These effects were largely independent of surgery type, except for a lasting reduction of ghrelin in the SG subgroup, and more pronounced increases in proglucagon products, mainly glicentin and oxyntomodulin, and in the cardiovascular risk marker Trimethylamine-N-oxide (TMAO) within the RYGB subgroup. Despite similar demographic and clinical features, participants 10 years after surgery showed a more favorable metabolic profile compared with the control group, in conjunction with a dramatic increase of postprandial proglucagon product secretion.

CONCLUSIONS

We demonstrate that cardiorenal and metabolic benefits of bariatric surgery remain robust and largely unchanged ten years postoperatively and are associated with durable effects on gastrointestinal- muscle- and adipose tissue-secreted hormones.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04170010.

Neutrophil-derived Activin-A moderates their pro-NETotic activity and attenuates collateral tissue damage caused by Influenza A virus infection

Background

Pre-neutrophils, while developing in the bone marrow, transcribe the Inhba gene and synthesize Activin-A protein, which they store and release at the earliest stage of their activation in the periphery. However, the role of neutrophil-derived Activin-A is not completely understood.

Methods

To address this issue, we developed a neutrophil-specific Activin-A-deficient animal model (S100a8-Cre/Inhba fl/fl mice) and analyzed the immune response to Influenza A virus (IAV) infection. More specifically, evaluation of body weight and lung mechanics, molecular and cellular analyses of bronchoalveolar lavage fluids, flow cytometry and cell sorting of lung cells, as well as histopathological analysis of lung tissues, were performed in PBS-treated and IAV-infected transgenic animals.

Results

We found that neutrophil-specific Activin-A deficiency led to exacerbated pulmonary inflammation and widespread hemorrhagic histopathology in the lungs of IAV-infected animals that was associated with an exuberant production of neutrophil extracellular traps (NETs). Moreover, deletion of the Activin-A receptor ALK4/ACVR1B in neutrophils exacerbated IAV-induced pathology as well, suggesting that neutrophils themselves are potential targets of Activin-A-mediated signaling. The pro-NETotic tendency of Activin-A-deficient neutrophils was further verified in the context of thioglycollate-induced peritonitis, a model characterized by robust peritoneal neutrophilia. Of importance, transcriptome analysis of Activin-A-deficient neutrophils revealed alterations consistent with a predisposition for NET release.

Conclusion

Collectively, our data demonstrate that Activin-A, secreted by neutrophils upon their activation in the periphery, acts as a feedback mechanism to moderate their pro-NETotic tendency and limit the collateral tissue damage caused by neutrophil excess activation during the inflammatory response.

T Cell Immunity in Human Papillomavirus-Related Cutaneous Squamous Cell Carcinoma-A Systematic Review

Cutaneous squamous cell carcinoma (cSCC) is an invasive malignancy that disproportionately afflicts immunosuppressed individuals. The close associations of cSCC with immunosuppression and human papillomavirus (HPV) infection beget the question of how these three entities are intertwined in carcinogenesis. By exploring the role of T cell immunity in HPV-related cSCC based on the existing literature, we found that the loss of T cell immunity in the background of β-HPV infection promotes cSCC initiation following exposure to environmental carcinogens or chronic trauma. This highlights the potential of developing T-cell centred therapeutic and preventive strategies for populations with increased cSCC risk.

Genetic influences on circulating retinol and its relationship to human health

Retinol is a fat-soluble vitamin that plays an essential role in many biological processes throughout the human lifespan. Here, we perform the largest genome-wide association study (GWAS) of retinol to date in up to 22,274 participants. We identify eight common variant loci associated with retinol, as well as a rare-variant signal. An integrative gene prioritisation pipeline supports novel retinol-associated genes outside of the main retinol transport complex (RBP4:TTR) related to lipid biology, energy homoeostasis, and endocrine signalling. Genetic proxies of circulating retinol were then used to estimate causal relationships with almost 20,000 clinical phenotypes via a phenome-wide Mendelian randomisation study (MR-pheWAS). The MR-pheWAS suggests that retinol may exert causal effects on inflammation, adiposity, ocular measures, the microbiome, and MRI-derived brain phenotypes, amongst several others. Conversely, circulating retinol may be causally influenced by factors including lipids and serum creatinine. Finally, we demonstrate how a retinol polygenic score could identify individuals more likely to fall outside of the normative range of circulating retinol for a given age. In summary, this study provides a comprehensive evaluation of the genetics of circulating retinol, as well as revealing traits which should be prioritised for further investigation with respect to retinol related therapies or nutritional intervention.

Current Insights in Prolactin Signaling and Ovulatory Function

Prolactin (PRL) is a pleiotropic hormone released from lactotrophic cells of the anterior pituitary gland that also originates from extrapituitary sources and plays an important role in regulating lactation in mammals, as well as other actions. Acting in an endocrine and paracrine/autocrine manner, PRL regulates the hypothalamic-pituitary-ovarian axis, thus influencing the maturation of ovarian follicles and ovulation. This review provides a detailed discussion of the current knowledge on the role of PRL in the context of ovulation and ovulatory disorders, particularly with regard to hyperprolactinemia, which is one of the most common causes of infertility in women. Much attention has been given to the PRL structure and the PRL receptor (PRLR), as well as the diverse functions of PRLR signaling under normal and pathological conditions. The hormonal regulation of the menstrual cycle in connection with folliculogenesis and ovulation, as well as the current classifications of ovulation disorders, are also described. Finally, the state of knowledge regarding the importance of TIDA (tuberoinfundibular dopamine), KNDγ (kisspeptin/neurokinin B/dynorphin), and GnRH (gonadotropin-releasing hormone) neurons in PRL- and kisspeptin (KP)-dependent regulation of the hypothalamic-pituitary-gonadal (HPG) axis in women is reviewed. Based on this review, a rationale for influencing PRL signaling pathways in therapeutic activities accompanying ovulation disorders is presented.

Insights into How Plant-Derived Extracts and Compounds Can Help in the Prevention and Treatment of Keloid Disease: Established and Emerging Therapeutic Targets

Keloid is a disease in which fibroblasts abnormally proliferate and synthesize excessive amounts of extracellular matrix, including collagen and fibronectin, during the healing process of skin wounds, causing larger scars that exceed the boundaries of the original wound. Currently, surgical excision, cryotherapy, radiation, laser treatment, photodynamic therapy, pressure therapy, silicone gel sheeting, and pharmacotherapy are used alone or in combinations to treat this disease, but the outcomes are usually unsatisfactory. The purpose of this review is to examine whether natural products can help treat keloid disease. I introduce well-established therapeutic targets for this disease and various other emerging therapeutic targets that have been proposed based on the phenotypic difference between keloid-derived fibroblasts (KFs) and normal epidermal fibroblasts (NFs). We then present recent studies on the biological effects of various plant-derived extracts and compounds on KFs and NFs. Associated ex vivo, in vivo, and clinical studies are also presented. Finally, we discuss the mechanisms of action of the plant-derived extracts and compounds, the pros and cons, and the future tasks for natural product-based therapy for keloid disease, as compared with existing other therapies. Extracts of Astragalus membranaceus, Salvia miltiorrhiza, Aneilema keisak, Galla Chinensis, Lycium chinense, Physalis angulate, Allium sepa, and Camellia sinensis appear to modulate cell proliferation, migration, and/or extracellular matrix (ECM) production in KFs, supporting their therapeutic potential. Various phenolic compounds, terpenoids, alkaloids, and other plant-derived compounds could modulate different cell signaling pathways associated with the pathogenesis of keloids. For now, many studies are limited to in vitro experiments; additional research and development are needed to proceed to clinical trials. Many emerging therapeutic targets could accelerate the discovery of plant-derived substances for the prevention and treatment of keloid disease. I hope that this review will bridge past, present, and future research on this subject and provide insight into new therapeutic targets and pharmaceuticals, aiming for effective keloid treatment.