Search Results (175)

Sarcoidosis is a multisystem granulomatous disorder of uncertain origin which still presents major therapeutic dilemmas. Longstanding dependence on corticosteroids, while effective for acute inflammation, carries considerable adverse effects over time. Advances in deciphering sarcoidosis pathobiology—including aberrant Janus kinase (JAK)- signal transducer and activator of transcription (STAT) signaling, mechanistic target of rapamycin (mTOR)-driven metabolic shifts, Th1/Th17.1 immune skewing, effector T-cell exhaustion, and granuloma-centered cytokine circuits—have revealed several targets for intervention. The treatment options are rapidly changing: the SARCORT trial showed that low-dose prednisolone is non-inferior to higher prednisolone doses; the pivotal PREDMETH trial validated methotrexate as a feasible first-line steroid-sparing option; efzofitimod, a novel immunomodulator targeting neuropilin-2, produced steroid-reducing effects in Phase IIbut not in Phase III trials; and JAK inhibitors are accumulating evidence across cutaneous and systemic presentations. The 2025 World Association for Sarcoidosis and Other Granulomatoses (WASOG) statement supports a move toward earlier steroid-sparing approaches. This review methodically connects sarcoidosis molecular and pathophysiological mechanisms to new targeted treatments, examines clinical trial evidence, and proposes future directions toward biomarker-driven individualized care. Full article

Semaphorin 3A (Sema3A), a known axon chemorepulsive protein during development, is localised in perineuronal nets (PNNs) in the adult brain. PNNs are condensed aggregates of extracellular matrix molecules surrounding specific types of neurons, which regulate neuroplasticity and memory. However, the role of PNN-associated Sema3A in these processes remains unclear. To address this topic, we investigated the contribution of Sema3A to cerebellum-dependent learning and memory in adult mice using the eyeblink conditioning (EBC) paradigm. We interfered with Sema3A signalling by employing: (i) a molecular approach, in which secreted Sema3A receptors (neuropilin-1 bodies) were expressed in the anterior interposed nuclei (AIN) via viral vector injection; and (ii) a genetic approach, using mutant mice with impaired Sema3A signalling (K108N mice). Mice expressing neuropilin-1 bodies showed reduced EBC performance at the beginning of the memory retention phase. However, increased inflammation was found in the AIN of these mice, challenging the interpretation of these findings. K108N mice showed enhanced EBC performance at the beginning of the memory retention phase. No synaptic structural changes were detected in the AIN of K108N mice at the end of the EBC paradigm. Based on our findings in K108N mice, constitutively altered Sema3A signalling is associated with subtle improvement in cerebellar memory. Full article

Semaphorins are a large family of proteins originally identified for their roles in axon guidance during neural development. Recent findings have established the importance of semaphorins members in modulating diverse immune responses of T cells in vitro and in vivo. Class 3 semaphorins, typified by Sema3A, signal through Neuropilin-1 and Plexin-A receptors in an activation-dependent manner, suppressing effector proliferation while promoting regulatory T cell stability and shaping cytokine profiles in autoimmunity and cancer. Sema3E and Sema3F similarly fine-tune host defense and inflammation by directing Th1/Th17 responses or restraining aberrant chemotaxis. Class 4 members, such as Sema4A and Sema4D, engage Plexin-B1, Plexin-D1, and CD72 to deliver both “forward” co-stimulatory and “reverse” signals: they amplify CD4⁺ and CD8⁺ effector functions, support T helper-B cell crosstalk, and influence tumor immunity via receptor shedding and bidirectional signaling. Finally, although less well defined, class 7 Sema7A operates indirectly—through APCs and Tregs—to regulate inflammatory recall responses and Th1/Th17 driven pathology. Together, these semaphorin-mediated pathways underscore a complex, context-dependent network that balances protective immunity against immunopathology, offering novel therapeutic targets in autoimmunity, infection, and cancer. Full article

Mitochondrial dysfunction drives persistent inflammation in severe asthma, yet its upstream metabolic regulation remains unclear. Induced sputum from patients with severe asthma was analyzed and integrated with transcriptomic datasets from independent cohorts. Two mouse models (C57BL/6J) were used for in vivo validation with multi-omics profiling, and mechanistic studies were performed in air–liquid interface-cultured primary human airway epithelial cells. Glutathione reduced form (GSHr) was markedly depleted in sputum and associated with poor disease control and mixed granulocytic inflammation in patients with severe asthma. Multi-omics analyses revealed coordinated disruption of glutathione (GSH) metabolism, including oxidized GSH accumulation, reduced synthesis and glutathione-S-transferase activity, and impaired mitochondrial GSH transport. GSH supplementation alleviated airway inflammation, oxidative stress, and mitochondrial dysfunction, whereas pharmacological inhibition of GST exacerbated these effects. Mitochondrial analyses identified suppressed SLC25A39 expression as a key mediator of defective GSH transport and redox imbalance. Transcriptomic profiling of airway biopsies showed upregulation of Neuropilin-1 (Nrp1), closely associated with altered glutathione pathways. Targeting the Nrp1 b1 domain restored mitochondrial GSH metabolism and attenuated airway inflammation. These findings identify an Nrp-centered metabolic pathway that disrupts mitochondrial homeostasis and drives inflammatory amplification, highlighting mitochondria-targeted therapeutic strategies for severe asthma. Full article

Background: We investigated whether a water extract of Lilii bulbus (Lilium lancifolium Thunberg; WELB) could modulate inhibitory synaptic organization in a mouse model of pentylenetetrazol (PTZ)-induced kindling. Methods: Starting 14 days prior to the initial PTZ challenge, WELB (500 mg/kg) was delivered via oral gavage once daily. This treatment regimen was maintained for a total of 40 days, spanning the entire period until the animals reached the fully kindled state. Results: Behavioral assessments revealed that WELB treatment significantly reduced seizure severity and Racine scores, prolonged the latency to clonic seizures, and shortened seizure duration, demonstrating potent anticonvulsant activity. Two-photon calcium imaging further showed that WELB markedly suppressed PTZ-induced neuronal hyperexcitability in the posterior parietal cortex, accompanied by decreased expression of neuronal activation markers, including c-fos, phosphorylated-calcium/calmodulin-dependent protein kinase IIα (p-CaMKIIα), and N-methyl-D-aspartate receptor 1 (NR1). In the hippocampus, WELB modulated the expression of GABAergic interneuron markers [glutamate decarboxylase 67 (GAD67), vesicular GABA transporter (VGAT), parvalbumin (PV), somatostatin (SOM)] and upregulated GABAergic gene transcripts [GABA-A receptor α1 subunit (Gabra1), GABA-A receptor α2 subunit (Gabra2), GABA transporter 1 (Gat1), GABA transporter 3 (Gat3), PV, SOM, cholecystokinin (CCK)] that were downregulated by PTZ kindling. Moreover, WELB enhanced the expression of GABAergic synaptic organization-related proteins (gephyrin, collybistin, neurexin-1β, neuroligin-2, and neuropilin-2), indicating its regulatory effect on inhibitory synaptic integrity. Conclusions: Collectively, these findings suggest that WELB may exert its anticonvulsant effects by functionally remodeling GABAergic synaptic organization-related factors, thereby restoring inhibitory circuit integrity and providing a mechanism-based therapeutic strategy for epilepsy and seizure-related neurological disorders. Full article

Background/Objectives: Olfactory dysfunction and dysgeusia are common neurosensory manifestations of Coronavirus Disease 2019 (COVID-19), affecting approximately 60% of patients. These symptoms have been mechanistically linked to receptors involved in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) cell entry, including angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), furin, and neuropilin-1 (NRP1), which are highly expressed in the olfactory epithelium. Nevertheless, clinical evidence supporting a direct association between receptor expression and sensory impairment remains inconsistent. Methods: We conducted a multicenter, observational, cross-sectional study including 104 adults with polymerase chain reaction–confirmed SARS-CoV-2 infection during the first and second pandemic waves. Approximately 75 days after diagnosis, nasal and/or pharyngeal samples were obtained to quantify gene expression levels of ACE2, TMPRSS2, furin, and NRP1 using quantitative polymerase chain reaction. Olfactory dysfunction and dysgeusia were recorded as dichotomous variables. Logistic regression analyses were performed with adjustment for age, sex, and race, considering receptor expression as continuous variables and as tertiles. Missing data were addressed using multiple imputation methods. Results: Olfactory dysfunction was reported by 37.5% of participants, and dysgeusia by 36.5%. No statistically significant associations were observed between baseline expression levels of ACE2, TMPRSS2, furin, or NRP1 and the presence of olfactory dysfunction or dysgeusia in either adjusted continuous or categorical models. Although these associations did not reach statistical significance, higher ACE2 and furin expression showed a nonsignificant trend toward an increased probability of sensory alterations, whereas intermediate NRP1 levels were associated with lower disease severity. Conclusions: COVID-19-related olfactory dysfunction and dysgeusia do not appear to be directly determined by isolated baseline expression of SARS-CoV-2 entry receptors. These findings support a multifactorial and dynamic pathophysiological model involving temporal receptor regulation, inflammatory processes, and host-related factors, highlighting the need for longitudinal and interventional studies. Full article

Although the SARS-CoV-2 pandemic no longer poses a global emergency, the virus continues to diversify and acquire immunoevasive properties. Understanding the molecular pathways that shape SARS-CoV-2 pathogenesis has become essential. In this paper, we summarize the most recent current evidence on how the spike protein structurally evolves, on changes in key non-structural proteins, such as nsp14, and on host factors, such as TMPRSS2 and neuropilin-1. These changes, together, shape viral entry, replication fidelity and interferon antagonism. Given the emerging Omicron variants of SARS-CoV-2, recent articles in the literature, cryo-EM analyses, and artificial intelligence-assisted mutational modeling were analyzed to infer and contextualize mutation-driven mechanisms. It is through these changes that the virus adapts and evolves, such as optimizing angiotensin-converting enzyme binding, modifying antigenic surfaces, and accumulating mutations that affect CD8⁺ T-cell recognition. Multi-omics data studies further support SARS-CoV-2 pathogenesis through convergent evidence linking viral adaptation to host immune and metabolic reprogramming, as occurs in myocarditis, liver injury, and acute kidney injury. By integrating proteomic, transcriptomic, and structural findings, this work presents how the virus persists and dictates disease severity through interferon antagonism (ORF6, ORF9b, and nsp1), adaptive immune evasion, and metabolic rewiring. All these insights underscore the need for next-generation interventions that provide a multidimensional framework for understanding the evolution of SARS-CoV-2 and guiding future antiviral strategies. Full article

(1) Background: Ulcerative colitis (UC) is a persistent inflammatory condition of the intestine, characterized by dysregulated T cell-mediated immune responses. Curcumin (CUR), a common food additive and health supplement, is noted for possessing anti-inflammatory and immunomodulatory properties. Nevertheless, the molecular mechanisms underlying its therapeutic effects remain incompletely elucidated. This research aims to investigate the therapeutic mechanisms of CUR in UC, focusing on its role in restoring T cell homeostasis by modulating TIGIT and Neuropilin-1 (NRP1). (2) Methods: We employed a DSS-induced murine colitis model, combined with network pharmacology, molecular docking, protein–protein interaction docking, molecular dynamics simulations, and invitro assays with Jurkat T cells. (3) Results: CUR markedly ameliorated clinical manifestations and histopathology in DSS-treated mice, restoring the balance of T cell and memory T cell subsets. Computational predictions and experimental validation showed that CUR downregulated TIGIT and NRP1 expression in inflamed colonic tissue and directly inhibited their expression in activated T cells invitro. (4) Conclusions: This study reveals a novel immunoregulatory mechanism of this natural compound. These findings suggest CUR modulates TIGIT/NRP1 to inhibit excessive T cell activation and restore immune homeostasis in UC. Full article

Liposomes modified with slightly acidic pH-sensitive peptides (SAPSp-lipo) are effectively delivered to tumor tissues, followed by cellular uptake in the tumor microenvironment. Although SAPSp-lipo can penetrate tumor tissues via the interspace route between cancer cells and the extracellular matrix (ECM), penetration needs to be enhanced to deliver liposomes into tumor cores comprising malignant cancer cells. To enhance the intratumoral penetration of SAPSp-lipo, we focused on the internalizing RGD peptide (iRGD), which can penetrate tumor tissue, differing from the penetration mechanism of SAPSp. In this study, we developed liposomes modified with iRGD-conjugated SAPSp (SAPSp-iRGD-lipo). Compared with SAPSp-lipo, SAPSp-iRGD-lipo was delivered to deeper regions within both spheroids and tumor tissues. The enhanced penetration was suppressed by a co-treatment with a Neuropilin-1 inhibitor, and the fluorescence signals from intratumorally injected SAPSp-iRGD-lipo were localized in Neuropilin-1-expressing regions, indicating a Neuropilin-1-mediated tumor penetration. Moreover, SAPSp-iRGD-lipo reduced F-actin formation in monolayered cells and was not localized in F-actin-rich regions in tumors, suggesting that SAPSp-iRGD-lipo facilitates tumor penetration through actin depolymerization. In addition, anticancer siRNA delivered by SAPSp-iRGD-lipid nanoparticles effectively induced apoptosis in cells under slightly acidic conditions. Taken together, SAPSp-iRGD-modified nanoparticles represent a novel class of tumor-penetrable and microenvironment-responsive drug carriers capable of efficient intratumoral delivery and therapeutic activity. Full article

Myocardial infarction (MI) remains a leading cause of mortality worldwide, yet effective cardioprotective strategies remain limited in clinical settings. Vascular endothelial growth factor B (VEGFB) has emerged as a promising therapeutic candidate in MI, but the role of its co-receptor, Neuropilin-1 (NRP1), in cardiomyocyte (CM) survival under ischemic stress remains poorly understood. Here, we investigated VEGFB-NRP1 signaling using an in vivo zebrafish model of cardiac injury as well as in vitro hypoxia models in CMs. We demonstrated that VEGFB overexpression conferred protection against ischemic injury and enhanced cardiac regeneration in the zebrafish heart. Mechanistically, we showed that VEGFB treatment enhances CM viability through reducing reactive oxygen species (ROS), ferroptosis activation, and preserving mitochondrial integrity. We also demonstrated that NRP1 knockdown in the CMs abolished the VEGFB-mediated protective effects, indicating the significant role of NRP1 signaling in VEGFB-induced cardioprotective effects in MI. Lastly, using transcriptome analysis, we confirmed that VEGFB induces anti-apoptotic and anti-ferroptosis gene programs in CMs in response to hypoxic stress. Collectively, our findings provide mechanistic insight into cell death activation pathways, including ferroptosis, in response to ischemic stress and further validate the therapeutic potential of VEGFB in promoting CM survival in ischemic heart disease. Full article

CD9 protein belongs to a family of proteins called tetraspanins, so named for their four-transmembrane-spanning architectures. These proteins are located in domains in the plasmatic membrane, called tetraspanin-enriched microdomains (TEMs). Several proteases and cellular receptors for virus entry cluster into TEMs, suggesting that TEMs are preferred virus entry portals. Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein mediates virus attachment and entry into cells by binding to human angiotensin-converting enzyme 2 (ACE-2). In addition, the secretory, type-I membrane-bound SARS-CoV-2 S protein is synthesized as a precursor (proS) that undergoes posttranslational cleavages by host cell proteases, such as furin and TMPRSS2. Moreover, it has been shown that neuropilin-1 (NRP1), which is known to bind furin-cleaved substrates, potentiates SARS-CoV-2 infectivity. Our results indicate that CD9 facilitates SARS-CoV-2 infection. In addition, we show how knocking out CD9 leads to a decrease in the expression of NRP1, a protein that improves SARS-CoV-2 infection. Furthermore, we show that CD9 colocalizes with ACE-2, NRP1, furin, and TMPRSS2 at the plasma membrane; that the absence of CD9 decreases the expression of these proteins on the plasma membrane CD9-enriched microdomains, and that CD9 interacts with ACE2. In conclusion, our data suggest that CD9 facilitates SARS-CoV-2 infection and that CD9 brings together different host proteins involved in SARS-CoV-2 attachment and entry into host cells, such as ACE2, NRP1, furin, and TMPRSS2. Importantly, the fact that a blocking antibody targeting CD9 can effectively reduce SARS-CoV-2 titers highlights not only the mechanistic role of CD9 in viral entry but also offers translational potential, suggesting that tetraspanin-targeting antibodies could be developed as therapeutic agents against SARS-CoV-2 and possibly other coronaviruses, with meaningful implications for clinical intervention. Full article

Background/Objectives: Medulloblastoma (MB) is the second leading cause of cancer-related death in children. Its tumor microenvironment (TME) includes endothelial, glial, and immune cells that influence tumor architecture and progression. Neuropilin-1 (NRP1), a co-receptor for semaphorins and vascular endothelial growth factor (VEGF), is expressed in various cell types during oncogenesis, yet its role in MB progression remains unclear. This study aimed to evaluate the expression and localization of NRP1 and glial fibrillary acidic protein (GFAP) in MB tissue. Methods: We analyzed MB tissue samples using immunohistochemistry, immunofluorescence, and quantitative PCR. Samples were stratified by molecular subgroup (WNT, SHH, non-WNT/non-SHH). We assessed NRP1 expression in tumor-associated microglia/macrophages (TAMs) and endothelial cells, as well as GFAP expression in astrocytes and tumor cells. Histopathological correlations and survival analyses were also conducted. Results: NRP1 was consistently expressed by TAMs across all MB molecular subgroups. Tumor vasculature showed strong endothelial NRP1 expression, while perivascular astrocytic coverage was frequently absent. Astrocytic processes exhibited spatial differences according to tumor histology. In SHH-MBs, a subset of tumor cells showed aberrant GFAP expression, which correlated with tumor recurrence or progression. Conclusions: NRP1 and GFAP display distinct expression patterns within the MB microenvironment, reflecting subgroup-specific biological behavior. Endothelial NRP1 positivity combined with limited vascular-astrocytic interaction and aberrant GFAP expression in SHH-MB may contribute to dysregulated angiogenesis and tumor progression. These findings warrant further investigation to explore their prognostic and therapeutic implications. Full article

Sepsis causes millions of deaths each year. Rapid, targeted therapy can reduce mortality rates. Both bacterial and viral pathogens can trigger sepsis, but the utility of commonly used inflammatory markers for differentiation remains controversial. Moreover, little is known about the time courses of alternative inflammatory parameters. The aim of this prospective, two-center observational study was to investigate the differences in the course of soluble Neuropilin-1 (sNRP-1) levels between bacterial and viral sepsis over a 7-day period. To be included, adult patients had to meet the SEPSIS-3 criteria and be diagnosed with either a bacterial or viral pathogen. Immunosuppressed patients were excluded. While IL-6, PCT, and CRP levels decreased consistently over time, sNRP-1 levels remained elevated in the bacterial group throughout the entire ICU stay. PCT (p < 0.001) and CRP (p = 0.016) levels were significantly associated with the course of sNRP-1. The AUC of sNRP-1 was 0.777 for discriminating between bacterial and viral infections on day 1. sNRP-1 remained stable and significantly higher in bacterial than in viral infections. Furthermore, the AUC values for discrimination ranged from acceptable to good, depending on the day of the ICU stay. sNRP-1 may serve as a potential tool to differentiate between bacterial and viral pathogens in sepsis. Full article

Background/Objectives: Neuropilin-1 (NRP1) is a key co-receptor for SARS-CoV-2, complementing the ACE2 receptor. Several investigations have documented highly conserved sequences in this receptor, supporting the implication of NRP1 as a key mediator in SARS-CoV-2 cellular entry mechanisms. Methods: To investigate this hypothesis, we examined 104,737 SARS-CoV-2 genome fastas from GISAID genomic data, corresponding to isolates collected between 2020 and 2025 in Mexico. Specifically, we focused on the RRAR motif, a known furin-binding site for NRP-1 and the binding site for ACE2 with the spike protein. Our analysis revealed high conservation (>98%) of the RRAR domain compared to a rapidly diminishing ACE2-binding domain. A complementary analysis, using Data from Gene Expression Omnibus (GEO, GSE150316), showed that NRP1 expression in lung tissue remains relatively stable, whereas ACE2 displayed high inter-individual variability and lower abundance compared to NRP1. Based on this evidence, we designed two humans–rats NRP1 siRNAs that were tested in vivo using a melittin-induced lung injury model. Results: The RT-PCR assays confirmed an effective NRP1 knockdown, and the siRNA-treated group showed a significant reduction in the lesions severity. These findings highlight NRP1 as a stable and relevant therapeutic target and suggest the protective potential of siRNA-mediated gene silencing. Conclusions: The evidence presented here supports the rational design of NRP1-directed therapies for multiple circulating SARS-CoV-2 variants in Mexico. Full article

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus responsible for Coronavirus Disease 2019 (COVID-19), utilizes its spike protein to infect host cells. In addition to angiotensin-converting enzyme 2 (ACE2) and neuropilin-1 (NRP1), AXL acts as a spike protein receptor and mediates infection, especially in respiratory cells with low ACE2 expression. Angiotensin II (1–8) can be cleaved into shorter peptides within the biological system. Antibody-based binding assays showed that angiotensin II causes a two-fold increase in the binding between the spike protein and AXL, but not ACE2 or NRP1. While a longer peptide, angiotensin I (1–10), did not affect the spike–AXL binding, shorter lengths of angiotensin peptides exhibited enhancing effects. The C-terminal deletions of angiotensin II to angiotensin (1–7) or angiotensin (1–6) resulted in peptides with enhanced activity toward spike–AXL binding with a similar capacity as angiotensin II. In contrast, the N-terminal deletions of angiotensin II to angiotensin III (2–8) or angiotensin IV (3–8) as well as the N-terminal deletions of angiotensin (1–7) to angiotensin (2–7) or angiotensin (5–7) produced peptides with a more potent ability to enhance spike–AXL binding (2.7-fold increase with angiotensin IV). When valine was substituted for tyrosine at position 4 in angiotensin II or when tyrosine at position 4 was phosphorylated, spike–AXL binding was increased, suggesting that modifications to tyrosine trigger enhancement. Angiotensin IV also enhances spike protein binding to ACE2 and NRP1. Thus, angiotensin peptides may contribute to COVID-19 pathogenesis by enhancing spike protein binding and thus serve as therapeutic targets. Full article