Search Results (197)

Interferon-stimulated gene 15 (ISG15) is an interferon-induced ubiquitin-like protein that plays an important role in antiviral defense and inflammatory responses, primarily through the process of ISGylation, whereby ISG15 is covalently conjugated to target proteins. Beyond its intracellular functions, a portion of free unconjugated ISG15 is also released into the extracellular environment during infections and diseases such as cancer. Extracellular ISG15 is known to regulate immune cell activity and cytokine production. Despite its immune-modulatory role, how ISG15 is released from cells has remained unclear. In this study, we have identified a non-lytic mechanism by which human macrophages release ISG15. Using lipopolysaccharide (LPS) as a stimulus, we show that extracellular LPS triggers unconjugated ISG15 release by utilizing plasma membrane-localized Gasdermin D (GSDMD) pores. Mechanistically, LPS via the autocrine/paracrine action of type-I interferon (IFN) activates caspase-4 (Casp4) to cleave the N-terminal domain of GSDMD for the formation of cell surface GSDMD pores that permit the extracellular release of unconjugated ISG15 in the absence of lytic cell death. Together, our studies have identified the IFN-Casp4-GSDMD axis as a previously unrecognized non-classical pathway for unconjugated ISG15 release from cells. Full article

Impairment of the blood–nerve barrier (BNB) is associated with the pathogenesis of chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). This research analyzes the molecular mechanisms of immunoglobulin (Ig) G in patients with typical CIDP, CIDP variants (multifocal CIDP), and multifocal motor neuropathy in BNB-endothelial cells. IgG was purified from the sera of patients with typical CIDP (n = 15), multifocal CIDP (n = 14), multifocal motor neuropathy (MMN; n = 12), and healthy controls (HCs; n = 14). Molecular changes in the RNA-seq/high-content imaging system and permeability were evaluated after the incubation of human peripheral nerve microvascular endothelial cells (PnMECs) with IgG. RNA-seq and a pathway analysis using PnMECs showed that TNF-α, CCL20 (MIP-3α), and ICAM-1 were the centers of the upregulated gene pathways in patients with typical CIDP. TNF-α, VCAM-1, NF-κB, and CSF2 (GM-CSF) are important molecules in patients with multifocal CIDP. The high-content imaging system demonstrated that MIP-3, GM-CSF, and VCAM-1 increased after exposure to typical CIDP-IgG, claudin-5 decreased after exposure to IgG from patients with multifocal CIDP, and TNF-α and VCAM-1 increased after exposure to IgG from patients with MMN. The 10 kDa dextran permeability using coculture with PnMECs and pericytes increased after exposure to IgG from patients with typical CIDP and multifocal CIDP. This effect was reversed after incubation with GM-CSF neutralizing antibodies. Upregulation of MIP-3, GM-CSF, and VCAM-1 may contribute to the infiltration of leukocytes/lymphocytes/monocytes across the BNB into the PNS in typical CIDP. IgG from typical CIDP and multifocal CIDP may decrease barrier properties through autocrine GM-CSF from PnMECs. VCAM-1 upregulation through autocrine TNF secretion in PnMECs may induce lymphocyte entry across the BNB in MMN. Full article

Cutaneous melanoma is a highly aggressive skin cancer prone to relapse and metastasis. Surgery is often curative when combined with early screening and prevention. However, in recurrent or advanced disease, the development of new targeted and immune therapies has demonstrated promising clinical outcomes, although the acquisition of resistance limits their effectiveness. Thus, new therapeutic approaches are needed. Emerging data indicate that the Hedgehog (Hh) pathway, which is essential for embryonic development, is aberrantly reactivated in melanoma and may represent a promising therapeutic target. Here, we demonstrate its chronic up-modulation in a panel of patient-derived cell lines and, by investigating the underlying molecular mechanisms, we excluded mutations in the principal components of the pathway. We observed reduced PTCH1 and SUFU repressors expression and GLI2 upregulation as common melanoma features. At the same time, copious SHH release, the principal PTCH1 ligand, evidenced autocrine Hh signaling activation. Consistently, a tendency of greater level of this factor resulted higher in the blood of patients compared to controls, confirming the relevance of ligand-dependent trigger in melanoma. The therapeutic potential of inhibiting the Hh pathway is highlighted by the reduced proliferation and migration observed in the presence of clinically approved pharmacological Hh antagonists. Profiling inflammatory mediators revealed significant modulation upon treatment with SMO inhibitors, possibly affecting chemotactic and immune functions. Collectively, these findings provide deeper insight into the role of the Hh pathway in melanoma and support the potential repurposing of Hh inhibitors as therapeutic agents for melanoma. Full article

Adipose tissue and skeletal muscle are the foremost energy depots and locomotor organs; they orchestrate metabolic homeostasis through the secretion of cytokines via autocrine, paracrine, and endocrine pathways. This intricate interplay is pivotal in the pathogenesis of numerous metabolic disorders, encompassing obesity and muscle atrophy, as well as influencing meat quality in animal production. Despite its significance, unraveling the molecular mechanisms underlying muscle–adipose crosstalk remains a major challenge. Recent advancements in multi-omics technologies have facilitated the identification of a multitude of cytokines derived from adipose tissue and muscle, including adipokines, lipokines, myokines, and myogenic exosomes and adipose-derived exosomes containing various biomolecules. The functional roles of these cytokines have been elucidated through meticulous studies employing trans-well cultures and recombinant proteins. In this comprehensive review, we summarize the bidirectional roles of adipokines and myokines in key biological processes—such as muscle satellite cell differentiation, mitochondrial thermogenesis, insulin sensitivity, and lipid metabolism. By synthesizing these findings, we aim to provide novel insights into the treatment of metabolic diseases and the improvement of animal production. Full article

Thyrostimulin is a heterodimeric glycoprotein hormone composed of two subunits, GPA2 and GPB5, first identified in 2002. It is considered an ancestral member of the glycoprotein hormone family and is highly conserved across species, including vertebrates and invertebrates. Unlike classical pituitary glycoprotein hormones such as TSH, LH, and FSH, thyrostimulin appears to function predominantly through paracrine and autocrine mechanisms, with its expression reported in diverse tissues such as the pituitary, ovary, skin, and brain. In humans, thyrostimulin has been implicated in ovarian cancer cell proliferation, stem cell quiescence in the pituitary, and metabolic regulation. However, its role in metabolism remains unclear, with studies showing both beneficial and adverse effects such as weight loss in some models and elevated levels in polycystic ovary syndrome and metabolic syndrome patients. In Caenorhabditis elegans, orthologs of GPA2 and GPB5 have been shown to influence growth and intestinal function via a neuroendocrine pathway involving thyrotropin hormone-like peptides. These findings suggest that thyrostimulin has conserved multifunctional roles in development, metabolism, and endocrine signaling. The aim of this review is to summarize the structure–function relationships and the currently known roles of thyrostimulin and its subunits, GPA2/GPB5, particularly in the reproductive system, metabolic syndrome, skeletal development, and obesity. Full article

Insulin is a key anabolic hormone traditionally considered to be exclusively produced by pancreatic β-cells. Insulin exerts several systemic effects involved in glucose uptake and metabolism. In the retina, insulin signaling acts as a regulator of photoreceptor- retinal pigment epithelium (RPE) metabolic coupling as well as of neuronal survival via the PI3K/Akt and MAPK/ERK pathways. Impaired insulin signaling contributes to diabetic retinopathy, retinitis pigmentosa, and age-related degeneration by disrupting energy homeostasis and trophic support. However, growing evidence suggests that the retina, particularly RPE, locally synthesizes and secretes insulin. Although the role of local insulin production in the retina remains to be clarified, this discovery introduces a paradigm shift in retinal physiology, suggesting a self-sustaining insulin signaling system that supports glucose uptake, lipid metabolism, and neurovascular integrity. Emerging data indicate that RPE-derived insulin is stimulated by photoreceptor outer segment (POS) phagocytosis and may act through autocrine and paracrine mechanisms to maintain retinal function, even under conditions of systemic insulin deficiency. Understanding this extra-pancreatic insulin source opens new therapeutic perspectives aimed at enhancing local insulin signaling to preserve vision and prevent retinal degeneration. Thus, the objective of this review is to summarize current evidence on RPE-derived insulin and to discuss its potential implications for retinal homeostasis and disease. Full article

The carotid body is a peripheral chemoreceptor that consists of clusters of chemoreceptive type I cells, glia-like type II cells, afferent and efferent nerves, and sinusoidal capillaries and arterioles. Cells and nerves communicate through reciprocal chemical synapses and electrical coupling that form a “tripartite synapse,” which allows for the process of sensory stimuli within the carotid body involving neurotransmission, autocrine, and paracrine pathways. In this network there are a variety of neurotransmitters and neuromodulators including adenosine 5′-triphosphate (ATP). Carotid body cells and nerve fibre terminals express ATP receptors, i.e., purinergic receptors. Here we used double immunofluorescence associated with laser confocal microscopy to detect the ATP receptor P2X7 and pannexin 1 (an ATP permeable channel) in the human carotid body, as well as the petrosal and cervical sympathetic ganglia. Immunofluorescence for P2X7r and pannexin 1 forms a broad cellular network within the glomeruli of the carotid body, whose pattern corresponds to that of type II cells. Moreover, both P2X7r and pannexin 1 were also detected in nerve profiles. In the petrosal ganglion, the distribution of P2X7r was restricted to satellite glial cells, whereas in the cervical sympathetic ganglion, P2X7r was found in neurons and glial satellite cells. The role of this purinergic receptor in the carotid body, if any, remains to be elucidated, but it probably provides new evidence for gliotransmission. Full article

Thyroid hormones are fundamental regulators of cellular differentiation, development, and metabolism. Their receptors are expressed in reproductive tissues, including the ovary, and dysregulation of thyroid hormone homeostasis has been associated with menstrual disturbances, infertility, and adverse pregnancy outcomes. Bone morphogenetic protein (BMP) ligands and their receptors are functionally involved in gonadotropin-induced ovarian steroidogenesis in an autocrine or paracrine manner. In this study, we examined the effects of thyroid hormones on steroidogenesis and their interplay with BMP signaling by using human granulosa-like KGN cells and primary rat granulosa cells (GCs). In KGN cells, triiodothyronine (T3) enhanced forskolin-induced expression of key steroidogenic enzymes involved in both estradiol biosynthesis and progesterone synthesis/metabolism, whereas thyroxine (T4) exerted minimal effects. In rat GCs, T3 treatment increased follicle-stimulating hormone (FSH)-stimulated estradiol production without altering progesterone output. T3 pretreatment attenuated BMP-6-induced phosphorylation of Smad1/5/9 in KGN cells, accompanied by upregulation of inhibitory Smad6 and downregulation of the BMP type II receptor. Conversely, BMP-6 stimulation elevated thyroid hormone receptor β expression, indicating reciprocal regulatory interactions between thyroid hormone and BMP pathways. Collectively, these findings suggest that thyroid hormones modulate steroidogenesis, at least in part, through suppression of endogenous BMP-6 signaling in granulosa cells. Full article

Schwann cells (SCs) are central players in peripheral nerve repair, facilitating axonal regrowth, remyelination, and modulation of the regenerative microenvironment. A pivotal driver of these functions is intracellular Ca²⁺ signaling, regulated by both endogenous Ca²⁺-permeable ion channels and engineered optogenetic actuators. Recent developments in optogenetics, particularly the application of Ca²⁺-permeable channelrhodopsins such as CapChR2, have enabled precise, light-controlled activation of SCs, allowing for targeted investigation of Ca²⁺-dependent pathways in non-neuronal cells. This review synthesizes emerging evidence demonstrating that optogenetically or endogenously induced Ca²⁺ influx in SCs leads to the release of a diverse set of neurotrophic and regulatory factors. These Ca²⁺-triggered secretomes modulate SC phenotypes and surrounding neurons, orchestrating axon regeneration and myelin repair via autocrine and paracrine mechanisms. We further discuss the roles of key endogenous Ca²⁺ channels—including transient receptor potential (TRP) channels and store-operated Ca²⁺ entry (SOCE; STIM/Orai)—in orchestrating SC activation under physiological and injury-induced conditions. By integrating insights from optogenetic manipulation and intrinsic signaling biology, this review proposes a conceptual framework in which Ca²⁺-triggered SC secretomes act as structural and functional scaffolds for nerve repair. We highlight how SC-derived factors shape the regenerative niche, influence adjacent neurons and glia, and modulate repair processes in peripheral and autonomic nerves. Full article

Cancer-associated cachexia is a multifaceted wasting syndrome characterized by progressive loss of skeletal muscle mass, systemic inflammation, and metabolic dysfunction and is particularly prevalent in gastrointestinal cancers. Physical activity has emerged as a promising non-pharmacological intervention capable of attenuating key drivers of cachexia. Exercise modulates inflammatory signaling (e.g., IL-6/STAT3 and TNF-α/NF-κB), enhances anabolic pathways (e.g., IGF-1/Akt/mTOR), and preserves lean body mass and functional capacity. Exercise-induced signaling molecules, known as exerkines, are key mediators of these benefits, which are released during physical activity and act in an autocrine, paracrine, and endocrine manner. However, many of these molecules also exhibit context-dependent effects. While they exert protective, anti-inflammatory, or anabolic actions when transiently elevated after exercise, the same molecules may contribute to cachexia pathogenesis when chronically secreted by tumors or in systemic disease states. The biological effects of a given factor depend on its origin, timing, concentration, and physiological milieu. This review presents recent evidence from clinical and experimental studies to elucidate how physical activity and exerkines may be harnessed to mitigate cancer cachexia, with particular emphasis on gastrointestinal malignancies and their unique metabolic challenges. Full article

Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus that establishes lifelong latent infection in CD34⁺ haematopoietic stem and progenitor cells. A unique subset of viral genes is expressed during latency, which functions to modulate cellular mechanisms without supporting viral replication. One potential function of these genes is to regulate the differentiation state of latently infected CD34⁺ cells, thereby preventing their progression into antigen-presenting cells, e.g., dendritic cells. In this study, we first compared CD34⁺ cells that supported productive and latent infections using the RV-TB40-BAC_KL7-SE-EGFP virus. Over a seven-day time course, the proportion of latently infected CD34⁺ cell subsets within the myeloid progenitor population remained similar to that in the mock-infected control. However, starting from day 3 post-infection, there was an increase in the proportion of the early progenitor subsets, including haematopoietic stem cells (HSCs) and multipotent progenitors (MPPs). In contrast, productively infected cells, which constituted less than 1% of the population, only accounted for a small portion of the myeloid progenitors. Importantly, our data revealed that the innate immune STING/p-TBK1/p-IRF3 pathway was activated in latently infected CD34⁺ cells, yet type I interferon (IFN) expression was decreased. This decrease was attributed to impaired p-IRF3 nuclear translocation, limiting the induction of an autocrine type I IFN response. However, treatment with IFN-β could induce myelopoiesis in latently infected cells. In summary, HCMV modulates a key component of the STING pathway to inhibit antiviral immune responses by decreasing the type I IFN-mediated cell differentiation of CD34⁺ progenitor cells. This study uncovered a new mechanism of latent HCMV-mediated regulation of the host cell differentiation response. Full article

Androgenetic alopecia (AGA) is a common form of hair loss characterized by androgen-driven tissue remodeling, including progressive follicular miniaturization and dermal fibrosis, which is accompanied by low-grade immune activation. However, the molecular mechanisms underlying this fibroimmune dysfunction remain poorly understood. Dermal fibroblasts (DFs) have been suggested as androgen-responsive stromal cells and a potential source of CXCL12, a chemokine implicated in fibroimmune pathology, but their precise role in AGA has not been fully established. In this study, we performed single-cell transcriptomic profiling of a testosterone-induced mouse model of AGA, with or without treatment of CXCL12-neutralizing antibody, to elucidate the pathological role of CXCL12 in mediating stromal-immune interactions. Our analysis suggested that DFs are the primary androgen-responsive population driving CXCL12 expression. Autocrine CXCL12-ACKR3 signaling in DFs activated TGF-β pathways and promoted fibrotic extracellular matrix deposition. In parallel, paracrine CXCL12-CXCR4 signaling reprogrammed Sox2⁺Twist1⁺ dermal papilla cells (DPCs) and promoted the accumulation of pro-fibrotic Trem2⁺ macrophages, contributing to impaired hair follicle regeneration. Notably, CXCL12 blockade attenuated these stromal and immune alterations, restored the regenerative capacity of DPCs, reduced pro-fibrotic macrophage infiltration, and promoted hair regrowth. Together, these findings identify CXCL12 as a central mediator of androgen-induced fibroimmune remodeling and highlight its potential as a therapeutic target in AGA. Full article

The incidence of Hashimoto’s disease (HD) increases with age and in people who have other autoimmune diseases. It is characterized by lymphocytic infiltration, fibrosis, and atrophy of the thyroid parenchyma with the simultaneous presence of thyroid peroxidase antibodies (ATPO) and/or thyroglobulin antibodies (ATG). Eicosanoids are formed via the cyclooxygenase (COX), lipoxygenase (LOX), and monooxygenase (CYP450) pathways with arachidonic acid (ARA), resulting in the production of epoxyeicosatrienoic acids (EETs) or hydroxyeicosatetraenoic acids (HETEs). These eicosanoids can act in an autocrine or paracrine manner on target cells. This study aimed to examine whether a gluten-free diet (GFD) can modulate the enzymatic pathways of the pro-inflammatory ARA cascade. The study material consisted of serum samples from Caucasian female patients with HD aged 18–55 years. Participants were enrolled in the study based on the presence of an ultrasound characteristic of HD, and elevated serum levels of anti-thyroid peroxidase antibodies and anti-thyroglobulin antibodies. Patients with confirmed celiac disease did not participate in the study. A total of 78 samples were analyzed, with 39 collected after 3 months of following a GFD. Eicosanoids (thromboxane B2, prostaglandin E2, leukotriene B4, and 16R-hydroxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid (16-RS HETE)) were extracted using high-performance liquid chromatography. The contribution of leukotriene (LTB) was analyzed in the LOX pathway, prostaglandins (PGE2) and thromboxane (TXB2) were selected for the involvement of the COX pathway, and 16RS HETE was used for the CYP450 pathway. All parameters were analyzed before and after a 3-month dietary intervention that included a gluten-free diet. In the obtained results, only one mediator, leukotriene B4, was significant (p < 0.05). The mean level on the initial visit was 0.202 ± 0.11 (SD), while it was 0.421 ± 0.27 (SD) on the subsequent visit, indicating a significant increase in its level after implementing a GFD. Although there was a trend in the CYP 450 pathway of decreased 16-RS HETE, the presented correlations show that thromboxane B4 and 16RS-HETE were positively correlated with the body mass and body fat mass of the examined patients. There was a trend in the CYP 450 pathway of decreased 16-RS HETE after GFD. Thromboxane B4 and 16RS-HETE levels before GFD were positively correlated with the body mass and body fat mass of the examined patients. A gluten-free diet in HD does not suppress the synthetic pathways of LOX, COX, or cytochrome P450 (CYP450). The level of adipose tissue has a greater impact on the inflammatory processes in HD than a gluten-free diet. This study does not confirm the suppressive effect of a gluten-free diet on the pro-inflammatory arachidonic acid cascade in any of the three analyzed mediator synthesis LOX, COX, CYP450 pathways. Full article

One of the most common malignant tumors worldwide is lung cancer, and it is associated with the highest death rate among all cancers. Traditional treatment options for lung cancer include radiation, chemotherapy, targeted therapy, and surgical resection. However, the survival rate is low, and the outlook is still dreadfully dire. The pursuit of a paradigm change in treatment approaches is, therefore, imperative. Tyrosine kinases (TKs), a subclass of protein kinases, regulate vital cellular function by phosphorylating tyrosine residues in proteins. Mutations, overexpression, and autocrine paracrine stimulation can transform TKs into oncogenic drivers, causing cancer pathogenesis. Tyrosine kinase inhibitors (TKIs) have emerged as an attractive targeted therapy option, especially for non-small cell lung cancer (NSCLC). However, resistance to TKIs, and adverse cardiovascular effects such as heart failure, atrial fibrillation, hypertension, and sudden death, are among the most common adverse effects of TKIs. There is increasing interest in plant-derived natural products in the hunt for powerful chemosensitizer and pathway modulators for enhancing TKI activity and/or overcoming resistance mechanisms. This highlights the mechanism of TKs’ activation in cancer, the role of TKIs in NSCLC mechanisms, and the challenges posed by TKI-acquired resistance. Additionally, we explored various plant-derived natural products’ bioactive compounds with the chemosensitizer and pathway-modulating potential with TKs’ inhibitory and anticancer effects. Our review suggests that a combination of natural products with TKIs may provide a novel and promising strategy for overcoming resistance in lung cancer. In future, further preclinical and clinical studies are advised. Full article

The unique secondary messenger 2′3′-cGAMP, produced by cGAS in response to cytosolic dsDNA, plays a critical role in activating innate immunity by binding to and activating STING via cell-intrinsic, autocrine, or paracrine mechanisms. Recently, we identified Rab18 as a novel, STING-independent binder of 2′3′-cGAMP. Binding of 2′3′-cGAMP to Rab18 promotes Rab18 activation and induces cell migration. However, the downstream mechanisms by which 2′3′-cGAMP-induced Rab18 activation regulates cell migration remain largely unclear. Herein, using phospho-profiling analysis, we identify MAPK signaling as a key downstream effector of the 2′3′-cGAMP/Rab18 axis that promotes the expression of FosB2 and drives cell migration. Furthermore, we identify MMP3 as a major transcriptional target of FosB2, through which the 2′3′-cGAMP/Rab18/MAPK/FosB2 signaling pathway positively regulates cell migration. Together, our findings provide new mechanistic insights into how 2′3′-cGAMP signaling controls cell migration and suggest the potential of MAPK inhibitors to block 2′3′-cGAMP-induced migratory responses. Full article