Rationale: Reconstruction of hair follicles (HFs) and eccrine sweat glands (ESGs) is essential for functional skin regeneration. In skin reconstruction research, we found that foreskin-derived epidermal cells reconstructed HF organoids unidirectionally, but not ESG organoids. Methods: To investigate key genes and pathways influencing the fate of ESG and HF, a transcriptome profiling of ESG placode-containing skin and HF placode-containing skin was employed, and key DEGs were identified and validated by RT-qPCR and immunofluorescence staining in mice and rats. Subsequently, adult human epidermal cell-derived organoids were reconstructed to probe functional roles and mechanisms of FGF7 and FGF10 by series of approaches integrating RT-qPCR, immunofluorescence-staining, WB, apoptosis assay, and pathway interference assay. Results: All members of FGF7 subfamily were among the key DEGs screened, the differential expression of FGF7 and FGF10 and their receptors FGFR1/FGFR2 was verified between ESG placode-containing skin and HF placode-containing skin. In vivo and in vitro Matrigel plug models showed that both FGF7 and FGF10 promoted fate transition of human epidermal cell-derived organoids to ESG phenotype organoids, FGF7 and FGF10 had a synergistic effect, and mainly function through the FGFR1/2-MEK1/2-ERK1/2 pathway. Conclusions: Adult epidermal cells can be manipulated to reconstruct personalized HF and ESG to meet different needs.

Klotho, an anti-aging protein, plays a vital role in diverse biological functions, such as regulating calcium and vitamin D levels, preventing chronic fibrosis, acting as an antioxidant and anti-inflammatory agent, safeguarding against cardiovascular and neurodegenerative conditions, as well as exerting anti-apoptotic, anti-senescence effects. Additionally, it contributes to metabolic processes associated with diabetes and exhibits anti-cancer properties. This protein is commonly expressed in organs, such as kidneys, brain, pancreas, parathyroid glands, ovaries, and testes. Recent research has highlighted its significance in human fertility. This narrative review provides insight into the involvement of Klotho protein in male and female fertility, as well as its potential role in managing human infertility in the future. In this study, a search was conducted on literature spanning from November 1997 to June 2024 across multiple databases, including PUBMED, SCOPUS, and Google Scholar, focusing on Klotho proteins. The search utilized keywords, such as \"discovery of Klotho proteins,\" \"Biological functions of Klotho,\" \"Klotho in female fertility,\" \"Klotho and PCOS,\" \"Klotho and cryopreservation,\" and \"Klotho in male infertility.\" Inclusion criteria comprised full-length original or review articles, as well as abstracts, discussing the role of Klotho protein in human fertility, published in English in various peer-reviewed journals. Exclusion criteria involved articles published in languages other than English. Hence, due to its anti-aging characteristics, Klotho protein presents potential roles in male and female fertility and holds promising prospects for reproductive medicine. Further, it holds the potential to become a valuable asset in addressing infertility concerns for both males and females.

Fibroblast Growth Factors and their receptors (FGFRs) comprise a cell signaling module that can stimulate signaling by Ras and the kinases Raf, MEK, and ERK to regulate animal development and homeostatic functions. In Caenorhabditis elegans, the sole FGFR ortholog EGL-15 acts with the GRB2 ortholog SEM-5 to promote chemoattraction and migration by the sex myoblasts (SMs) and fluid homeostasis by the hypodermis (Hyp7). Cell-specific differences in EGL-15 signaling were suggested by the phenotypes caused by egl-15(n1457), an allele that removes a region of its C-terminal domain (CTD) known to bind SEM-5. To determine how mutations altered EGL-15 activity in the SMs and Hyp7, we used the kinase reporter ERK-KTR to measure activation of the ERK ortholog MPK-1. Consequences of egl-15(n1457) were cell-specific, resulting in loss of MPK-1 activity in the SMs and elevated activity in Hyp7. Previous studies of Hyp7 showed that loss of the CLR-1 phosphatase causes a fluid homeostasis defect termed \"Clear\" that is suppressed by reduction of EGL-15 signaling, a phenotype termed \"Suppressor of Clear\" (Soc). To identify mechanisms that permit EGL-15 signaling in Hyp7, we conducted a genetic screen for Soc mutants in the clr-1; egl-15(n1457) genotype. We report the identification of SOC-3, a protein with putative SEM-5-binding motifs and PH and PTB domains similar to DOK and IRS proteins. In combination with the egl-15(n1457) mutation, loss of either soc-3, the GAB1 ortholog soc-1, or the SHP2 ortholog ptp-2, reduced MPK-1 activation. We generated alleles of soc-3 to test the requirement for the SEM-5-binding motifs, finding that residue Tyr356 is required for function. We propose that EGL-15-mediated SM chemoattraction relies solely on the direct interaction between SEM-5 and the EGL-15 CTD. In Hyp7, EGL-15 signaling uses two mechanisms: the direct SEM-5 binding mechanism; and an alternative, CTD-independent mechanism involving SOC-3, SOC-1, and PTP-2. This work demonstrates that FGF signaling uses distinct, tissue-specific mechanisms in development, and identifies SOC-3 as a potential adaptor that facilitates Ras pathway activation by FGFR.

Background/Objectives: Fibroblast growth factor 21 (FGF21) is a protein hormone involved in physiological conditions in the regulation of energy expenditure and several metabolic processes. The aim of this present study was to analyze the effect of successful kidney transplantations on the plasma FGF21 concentration and to study the factors which may influence plasma FGF21 concentration in patients in long time after kidney transplantation. Methods: This study consisted of two independent parts. The first part was a prospective observation of CKD patients in stage 5 before and then on the 14th and 30th day and 6 months after kidney transplantation. The second part of this study was the cross-sectional study completed in patients at least one year after kidney transplantation and the control group. In CKD patients directly before and during the early period after KTx, plasma FGF21 concentrations were measured four times (immediately before and 14 and 30 days and 6 months after KTx). In patients long time after kidney transplantation and in healthy subjects, plasma FGF21 concentration was measured once. Results: Forty patients with chronic kidney disease (CKD) who were either directly before or within the early period after kidney transplantation (KTx), 184 patients longtime after KTx and 50 healthy subjects were enrolled into this study. In CKD patients at the stage directly before receiving a KTx, the mean plasma FGF21 concentration was significantly higher than in the healthy subjects [1013.0 pg/mL versus 239.5 pg/mL, p < 0.001]. At 14, 30 days, and 6 months after the KTx, a significant decrease of plasma FGF21 was observed, with values of 322.5 pg/mL; 355.0 pg/mL; and 344.0 pg/mL (p < 0.001), respectively]. In patients long time after KTx, a negative correlation was found between the plasma FGF21 concentration and the estimated glomerular filtration rate and a positive correlation was found between the plasma FGF21 concentration and the BMI, the serum concentration of triglycerides, insulin, interleukin-6, CRP, and cystatin C. Conclusions: The plasma FGF21 concentration in patients with end-stage renal disease is higher than in healthy subjects and significantly decreases after a successful KTx. The plasma FGF21 concentration measured by ELISA in patients long time after kidney transplantation seems to be related to the degree of kidney function impairment and their metabolic status. The kidneys appear to be one of the main organs involved in the biodegradation and/or elimination of FGF21.

Fibroblast growth factor 7 (FGF7), also known as keratinocyte growth factor (KGF), is an important member of the FGF family that is mainly expressed by cells of mesenchymal origin while affecting specifically epithelial cells. Thus, FGF7 is widely expressed in diverse tissues, especially in urinary system, gastrointestinal tract (GI-tract), respiratory system, skin, and reproductive system. By interacting specifically with FGFR2-IIIb, FGF7 activates several downstream signal pathways, including Ras, PI3K-Akt, and PLCs. Previous studies of FGF7 mutants also have implicated its roles in various biological processes including development of essential organs and tissue homeostasis in adults. Moreover, more publications have reported that FGF7 and/or FGF7/FGFR2-IIIb-associated signaling pathway are involved in the progression of various heritable or acquired human diseases: heritable conditions like autosomal dominant polycystic kidney disease (ADPKD) and non-syndromic cleft lip and palate (NS CLP), where it promotes cyst formation and affects craniofacial development, respectively; acquired non-malignant diseases such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), mucositis, osteoarticular disorders, and metabolic diseases, where it influences inflammation, repair, and metabolic control; and tumorigenesis and malignant diseases, including benign prostatic hyperplasia (BPH), prostate cancer, gastric cancer, and ovarian cancer, where it enhances cell proliferation, invasion, and chemotherapy resistance. Targeting FGF7 pathways holds therapeutic potential for managing these conditions, underscoring the need for further research to explore its clinical applications. Having more insights into the function and underlying molecular mechanisms of FGF7 is warranted to facilitate the development of effective treatments in the future. Here, we discuss FGF7 genomic structure, signal pathway, expression pattern during embryonic development and in adult organs and mutants along with phenotypes, as well as associated diseases.

Traumatic brain injury (TBI) and spinal cord injury (SCI) are neurological conditions that result from immediate mechanical injury, as well as delayed injury caused by local inflammation. Furthermore, TBI and SCI often lead to secondary complications, including pressure wounds of the skin, which can heal slowly and are prone to infection. Pressure wounds are localized areas of damaged tissue caused by prolonged pressure on the skin due to immobility and loss of neurological sensation. With the aim to ameliorate these symptoms, we investigated whether fibroblast growth factors 2 (FGF-2) could contribute to recovery. FGF-2 plays a significant role in both neurogenesis and skin wound healing. We developed a recombinant fusion protein containing FGF-2 linked to elastin-like polypeptides (FGF-ELP) that spontaneously self-assembles into nanoparticles at around 33 °C. The nanoparticle\'s size was ranging between 220 and 250 nm in diameter at 2 μM. We tested this construct for its ability to address neuronal and skin cell injuries. Hydrogen peroxide was used to induce oxidant-mediated injury on cultured neuronal cells to mimic the impact of reactive oxidants released during the inflammatory response in vivo. We found that FGF-ELP nanoparticles protected against hydrogen peroxide-mediated injury and promoted neurite outgrowth. In the skin cell models, cells were depleted from serum to mimic the reduced levels of nutrients and growth factors in chronic skin wounds. FGF-ELP increased the proliferation and migration of human keratinocytes, fibroblasts, and endothelial cells. FGF-ELP is, therefore, a potentially useful agent to provide both neuroprotection and promotion of cellular processes involved in skin wound healing.

BACKGROUND: To assess the safety and efficacy of repeated intravitreal injections of RC28-E, a novel bispecific antibody that simultaneously binds vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in patients with neovascular age-related macular degeneration (AMD). This was a prospective, multicenter, open-label clinical trial; 37 patients with choroidal neovascularization secondary to AMD and best-corrected visual acuity (BCVA) letter scores between 73 and 34 were enrolled.
METHODS: Treatment regimens consisted of a 3-month loading phase and a pro re nata (PRN) maintenance phase. This study included three treatment groups: the 0.5, 1.0, and 2.0 mg RC28-E groups, with escalating doses ranging from 0.5 to 2.0 mg. Patients were evaluated monthly for 48 weeks. Safety was assessed based on ocular and systemic adverse events (AEs), pharmacokinetic characteristics, and the presence of anti-RC28-E antibodies. Efficacy was assessed using the mean change in BCVA and central subfield thickness (CST) from baseline to week 48.
RESULTS: Most AEs were mild or moderate. The most common AE was a minor injection-related subconjunctival hemorrhage (16.2%). The AEs did not increase with dose or repeated injections. At week 48, mean improvements in BCVA from baseline in the 0.5, 1.0, and 2.0 mg groups were 6.1 ± 8.3, 9.9 ± 10.7, and 7.6 ± 9.38 letters, respectively; mean reductions in CST in the three groups were 112.1 ± 160.5, 175.1 ± 212.4, and 128.7 ± 145.8 μm, respectively. The serum RC28-E concentrations in 95% of the patients were below the quantification limit of the assay. No significant change from baseline was observed in the mean plasma concentrations of VEGF or FGF over the 48 weeks of treatment. Pre-treatment antibodies to RC28-E were detected in 1 of the 37 patients. Antibodies to RC28-E were detected in two patients after dosing with RC28-E for 48 weeks.
CONCLUSIONS: RC28-E was well tolerated and exhibited an overall favorable safety profile with evidence of improvements in BCVA and anatomical parameters.

The 18-kDa isoform of basic fibroblast growth factor (bFGF/FGF2) lacks a conventional signal peptide sequence and is exported by a novel membrane-associated transport pathway. Extracellular vesicles (EVs) are increasingly recognized as mediators of intercellular communication in the lung, and our prior work demonstrates that EVs carry cargo that contributes to hyperoxic lung injury and are biomarkers for bronchopulmonary dysplasia. We used primary human bronchial epithelial (HBE), pulmonary artery endothelial (HPAE), and fibroblast (HNF) cells to determine whether FGF2 was secreted in EVs. EVs were isolated by ultracentrifugation from HBE, HPAE, and HNF exposed to either normoxia or hyperoxia, followed by nanoparticle tracking analysis and electron microscopy. Hyperoxia exposure increased the total EV number. All three cell types released FGF2-18kDa both directly into the extracellular environment (secretome), as well as in EVs. HBE released more FGF2-18kDa in EVs during hyperoxia, and these were internalized and localized to both nuclei and cytoplasm of recipient cells. By co-immunoprecipitation, we identified potential binding partners of FGF2-18kDa in the nuclei, including histone 1.2 (H1.2) binding protein, that may mediate downstream effects that do not involve FGF2 binding to cell surface receptors. FGF2-18kDa interaction with H1.2 binding protein may indicate a mechanism by which FGF2 secreted in EVs modulates cellular processes. FGF2 was also found to increase angiogenesis by Matrigel assay. Further studies are necessary to determine the biological relevance of FGF2 in EVs as modulators of lung injury and disease.NEW & NOTEWORTHY We found that multiple lung cell types release basic fibroblast growth factor (FGF2)-18kDa both directly into the extracellular environment (secretome), as well as in extracellular vesicles (EVs). Bronchial epithelial cells released more FGF2-18kDa in EVs during hyperoxia, which could be internalized rapidly by recipient cells. We also identified potential binding partners of FGF2-18kDa in nuclei that may mediate downstream effects that do not involve FGF2 binding to cell surface receptors. We also confirmed a potential angiogenic role for FGF2-18kDa.

SSR128129E (SSR) is a unique small-molecule inhibitor of fibroblast growth factor receptors (FGFRs). SSR is a high-affinity allosteric binder that selectively blocks one of the two major FGFR-mediated pathways. The mechanisms of SSR activity were studied previously in much detail, allowing the identification of its binding site, located in the hydrophobic groove of the receptor D3 domain. The binding site overlaps with the position of an N-terminal helix, an element exclusive for the FGF8b growth factor, which could potentially convert SSR from an allosteric inhibitor into an orthosteric blocker for the particular FGFR/FGF8b system. In this regard, we report here on the structural and functional investigation of FGF8b/FGFR3c system and the effects imposed on it by SSR. We show that SSR is equally or more potent in inhibiting FGF8b-induced FGFR signaling compared to FGF2-induced activation. On the other hand, when studied in the context of separate extracellular domains of FGFR3c in solution with NMR spectroscopy, SSR is unable to displace the N-terminal helix of FGF8b from its binding site on FGFR3c and behaves as a weak orthosteric inhibitor. The substantial inconsistency between the results obtained with cell culture and for the individual water-soluble subdomains of the FGFR proteins points to the important role played by the cell membrane.

Fibroblast growth factor 21 (FGF21) belongs to the FGF19 subfamily and acts systemically, playing a key role in inter-organ crosstalk. Ranging from metabolism, reproduction, and immunity, FGF21 is a pleiotropic hormone which contributes to various physiological processes. Although most of its production across species stems from hepatic tissues, expression of FGF21 in mice has also been identified in adipose tissue, thymus, heart, pancreas, and skeletal muscle. Elevated FGF21 levels are affiliated with various diseases and conditions, such as obesity, type 2 diabetes, preeclampsia, as well as cancer. Murine knockout models are viable and show modest weight gain, while overexpression and gain-of-function models display resistance to weight gain, altered bone volume, and enhanced immunity. In addition, FGF21-based therapies are at the forefront of biopharmaceutical strategies aimed at treating metabolic dysfunction-associated steatotic liver disease.