Immunological Investigations最新文献

Introduction: Cathepsin K (CTSK) is a lysosomal cysteine protease of the papain superfamily. The enzyme plays a key role in bone homeostasis. Immune cells such as dendritic cells, macrophages, and T cells all express CTSK. It modulates inflammation and immunity through NF-κB, TLR, and the RANKL/RANK/OPG axis. Overexpression or underexpression of CTSK appears in rheumatoid arthritis, periodontitis, tumors, and inflammatory bowel disease. Targeted inhibitors and monoclonal antibodies against CTSK are now emerging therapies.

Methods: Systematic literature search and critical review of experimental and clinical studies examining CTSK expression, genetic modulation, and targeted inhibition in inflammatory and immune-mediated disease models.

Results: Elevated CTSK correlates with disease activity and bone destruction; its inhibition reduces inflammatory cytokines, immune-cell infiltration, and extracellular-matrix degradation. Small-molecule inhibitors (odanacatib, MIV-711, ONO-5334) and biologics attenuate pathology in arthritis, periodontitis, and atherosclerosis.

Discussion: CTSK is a promising diagnostic biomarker and therapeutic target, yet its promise hinges on inhibitors that act only where needed, sparing other tissues. Next steps must therefore craft more selective allosteric compounds and test ways to confine them to diseased sites.

Background: Klebsiella pneumoniae (Kp) is a bacterial pathogen that results in diverse infections. NLRP12, one of the NLR family members, acts as an inflammasome in response to specific infections. Herein, the role and mechanisms of NLRP12 involving in severe Kp pneumonia were investigated.

Methods: SD rats were infected with Kp and manipulated with shNLRP12 lentivirus, macrophage M1 polarization inhibitor (abietic acid), and autophagy activator (rapamycin). Hematoxylin and eosin (HE) staining, bacterial load in lung tissue, and ELISA were used to assess lung tissue injury and inflammation in rats. NLRP12 and autophagy proteins LC3B II/I and p62 in lung tissues were detected by immunohistochemistry and western blot. Flow cytometric analyses were followed to calculate the proportion of M1 and M2 macrophages in BALF.

Results: In addition, NLRP12 was upregulated in lung tissue of rats with Kp infection-caused severe pneumonia, while NLRP12 knockdown enhanced Kp-induced M1 polarization of macrophages and exacerbated lung injury and inflammatory response. NLRP12 attenuated inflammation caused by Kp infection by reducing macrophage M1 polarization. Kp infection induced autophagy deficiency in rat lung tissues, while activation of autophagy could ameliorate Kp-induced lung injury and inflammation.

Conclusion: NLRP12 facilitates autophagy to affect macrophage M1 polarization and drives host defense against Kp infection.

Background: Extracellular vesicles (EVs) have been linked with cytokine transportation and shown promising therapeutic and diagnostic potential in sepsis. Therefore, this study investigates the levels of cytokines associated with sepsis EVs and explores their therapeutic and diagnostic values.

Research design and methods: Twenty sepsis patients and ten healthy controls were included in this study. Plasma samples were used to isolate EVs using the Invitrogen Total Exosome Isolation Kit. EVs were fully characterized, and the cytoprotective activity and cytokine profile were determined using MTT and multiplex assays.

Results: Sepsis significantly increased the release, size, poly dispersion index, cellular proliferative and cytoprotective effects of isolated EVs, as well as altering the contents of their cytokines/chemokines and growth factors. Seven proteins were detected in EVs isolated from sepsis, but not healthy control patients. Two factors, IL-10 and basic FGF, were detected at significantly different levels in EV samples from sepsis vs. healthy control group.

Conclusion: These findings indicate that the enrichment of IL-15, IL-10 and G-CSF in sepsis circulating EVs represents a biologically active protein signature with potential to both modulate the immune response and serve as a novel diagnostic biomarker.

Background: In multiple myeloma (MM), immune checkpoint blockade is being explored as a treatment strategy. However, the role of inhibitory checkpoint receptors on myeloid cells remains poorly understood. The aim of our study was to investigate the expression of PD-1 and TIM-3 on monocytes and monocytic myeloid-derived suppressor cells (M-MDSCs) and their contribution to early immune reconstitution.

Methods: The count of monocytic cells and expression of PD-1 and TIM-3 was assessed by flow cytometry.

Results: At the engraftment, monocyte subsets counts were similar to pre-transplant values, while the relative content of M-MDSCs was significantly higher. The frequencies of TIM-3-positive cells among intermediate and non-classical monocytes were significantly increased. Incubation of mononuclear cells of MM patients in remission with homeostatic cytokines led to a significant increase in intermediate monocytes and a trend to an increase in the M-MDSCs count and stimulated the expression of PD-1 and TIM-3. PD-1 and TIM-3 expression on monocytes and M-MDSCs inversely correlated with lymphocyte count at the engraftment. TIM-3 expression on monocytic cells was associated with regulatory T-cell count. After auto-HSCT, PD-1/TIM-3-expressing cells exhibited significantly elevated IL-10 production (with decreased TNFα production).

Conclusion: PD-1 and TIM-3 on monocytic cells may play a significant role in immune reconstitution.

Background: Primary biliary cholangitis (PBC) fundamentally manifests as an immune-mediated disorder where T cell-driven autoreactivity persists as the principal pathogenic mechanism. Despite this understanding, immunosuppressive therapies have failed to halt PBC. This underscores the imperative to identify novel mechanisms for immunoregulation in PBC treatment. Here, we investigated the activity and role of autophagy in liver-infiltrating T lymphocytes of PBC.

Methods: Liver tissues from PBC patients and a well-established PBC mouse model (dnTGFβRII, Tg) were analyzed by immunohistochemistry and immunofluorescence. Hepatic and splenic mononuclear cells and CD8⁺ T cells were isolated from Tg and wild-type mice. LC3BII, p62, and phospho-mTOR was detected by western blotting. Autophagic activity was assessed using CytoID staining and LC3BII turnover assay. Mitochondrial reactive oxygen species (mROS), T cell activation (IFN-γ, Granzyme B), and cell apoptosis were evaluated using flow cytometry.

Results: Our findings revealed the elevated expression of autophagic marker LC3B in hepatic-infiltrating T lymphocytes, particularly CD8⁺ T lymphocytes, from PBC patients and PBC mice. We observed a significant increase of autophagic flux in liver-infiltrating T lymphocytes, suggesting the functional activation of autophagy. Furthermore, we found that autophagy activation exhibits an inverse correlation with mROS generation. The mTOR signaling disruption may contribute to autophagy upregulation in liver-infiltrating T lymphocytes of PBC. Pharmacological inhibition of T lymphocyte autophagy yielded three principal outcomes: substantial attenuation of pro-inflammatory cytokine production, decreased CD8⁺ effector differentiation, and concomitant induction of mROS-mediated apoptosis.

Conclusion: Our study indicates autophagy is a critical survival mechanism for intrahepatic T lymphocytes such as CD8⁺ T cells, functioning through mROS quenching to maintain cellular viability and sustains liver inflammation. This evidence suggests that modulation of T lymphocyte autophagic processes within the hepatic microenvironment may disrupt immune activation, potentially decelerating PBC progression.

Background: The skin contains a complex immune network involving keratinocytes, Langerhans cells, tissue-resident memory T cells, regulatory T cells, and B cells that collectively maintain immune surveillance and homeostasis.

Methods: This review synthesizes current findings on the dual role of skin immunity in cancer, focusing on mechanisms of immune surveillance, evasion, and therapeutic restoration.

Results: Keratinocytes detect pathogens through pattern-recognition receptors and secrete cytokines such as IL-1, IL-6, IL-10, and TGF-β to balance inflammation. Langerhans cells capture antigens and activate T lymphocytes, while NK cells and cytotoxic T cells eliminate transformed cells. However, ultraviolet radiation and oncogenic viruses (e.g., β-HPVs) induce DNA mutations and immunosuppressive mediators that impair local immunity. Tumor cells further evade immune attack by upregulating checkpoint ligands (PD-L1, CTLA-4), secreting TGF-β and IL-10, and reprogramming metabolism to promote a hypoxic, tumor-supportive microenvironment.

Conclusion: Understanding how immune surveillance shifts toward immune escape remains a major challenge. Therapies targeting these mechanisms, checkpoint inhibitors, adoptive cell therapy, oncolytic viruses, microbiome modulation, and nanotechnology-based delivery, represent promising strategies to restore effective antitumor immunity in the skin.

Background: Multiple sclerosis (MS) is a neuroinflammatory, demyelinating disease with Epstein-Barr virus (EBV) suggested as a prerequisite for disease development. EBV expresses 44 microRNAs (miRNAs) with largely unknown functions, but they have been implicated in EBV-infected cell proliferation and immune evasion.

Objectives: This study investigates EBV miRNAs levels in whole blood and plasma exosomes at baseline and after treatment, and in relation to disease activity based on age-adjusted NfL ratios, in 50 newly diagnosed patients with relapsing-remitting MS (RRMS).

Methods: EBV miRNAs purified from whole blood and isolated plasma exosomes were measured by qPCR, using TaqMan Array Cards, and correlated to mRNA of GZMA, GZMH, IFN-γ, TNF-α, IL-10, IL-1B, and IL-1R1 in whole blood, measured by qPCR. Serum neurofilament light chain (NfL) and IL-6, plasma anti-EBNA1 antibody titers, occludin, and zonula occludens-1 were measured by various immunoassays.

Results: The miRNA profiling of whole blood revealed expression of BHRF1 miRNAs in most patients, indicating that EBV is in lytic phase or latency phase III. Higher levels of miR-BART14-3p were observed in patients classified with high disease activity. EBV miRNA levels correlated with anti-EBNA1 antibody titers, biomarkers of inflammation and tight junction proteins.

Objective: This study aimed to investigate the protective effects and underlying mechanisms of pachymic acid (PA), a natural triterpenoid compound, in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis (UC).

Methods: Disease severity was assessed using the disease activity index (DAI). Histological changes and mucus layer integrity were evaluated via hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining. Inflammatory cytokines and oxidative stress markers were measured using ELISA and biochemical assays. DNA damage was assessed by γH2AX immunofluorescence. Protein expression levels of tight junction markers, apoptosis regulators, and NF-κB signaling components were analyzed by Western blotting.

Results: PA administration significantly alleviated colitis symptoms, as indicated by reduced DAI scores, mitigation of colon shortening, preservation of colon histoarchitecture, and restoration of mucus secretion. PA suppressed the expression of pro-inflammatory cytokines and oxidative stress markers, enhanced endogenous antioxidant activity, and decreased γH2AX levels, indicating reduced DNA damage. Moreover, PA restored tight junction protein expression, improved the Bax/Bcl-2 ratio, and inhibited activation of the NF-κB signaling pathway.

Conclusion: PA effectively ameliorates colonic inflammation and epithelial barrier dysfunction in DSS-induced colitis, suggesting its potential as a therapeutic candidate for ulcerative colitis.

Objective: This study aims to elucidate how butyrate, a short-chain fatty acid, regulates the Treg/Th17 balance in ulcerative colitis (UC) via the cAMP-PKA/mTOR signaling pathway, offering novel treatment strategies.

Methods: Dextran sulfate sodium (DSS) was used to induce ulcerative colitis in a mouse model. Various butyrate dosages were administered to the mice. The mice's body weight, colon length, spleen index (SI), and disease activity index (DAI) were all assessed.HE staining and Masson staining were used for histopathological evaluation. Immunohistochemistry and RT-qPCR were applied to detect fibrosis markers. Flow cytometry, RT-qPCR, and ELISA were employed to analyze immune cell subsets and cytokines. RT-qPCR and Western blotting were utilized to explore the cAMP-PKA/mTOR signaling pathway. Specific inhibitors were used to further confirm the mechanism of its action.

Results: Butyrate treatmentreduced DAI and SI, and reversed pathological changes (weight loss, colon shortening, splenomegaly) in DSS-induced UC model mice, with the high-dose group showing the best recovery. It inhibited colon fibrosis,and decreased fibrosis markers. By regulating the regulatory T cell (Treg)/T helper 17 cell (Th17) balance, butyrate restored immune homeostasis. Flow cytometry showed DSS-induced immune imbalance was reversed in a dose-dependent manner. Additionally, butyrate modulated the cAMP-PKA/mTOR signaling pathway, reversing DSS-induced gene and protein expression changes. Specific inhibitor experiments confirmed that butyrate exerted its therapeutic effects via this pathway.

Conclusion: Butyrate can markedly alleviate acute UC intestinal inflammation and block chronic fibrosis progression. The bidirectional regulation of the cAMP-PKA/mTOR signaling pathway is the key mechanism for butyrate to restore immune homeostasis.

Background: Multiple sclerosis (MS) is an autoimmune disorder driven by myelin autoantigen-specific autoreactive T cells, yet the most effective disease-modifying therapies (DMTs) target B cells. The mechanism underlying this paradox remains unclear. Here, we identify dual-expressor cells (DEs) -a novel lymphocyte population with hybrid T and B cell characteristics, including co-expression of the T cell receptors (TCRαβ) and surface B cell receptors (BCRs), primarily IgM-as potential contributors to MS pathogenesis and inadvertent targets of anti-CD20 DMTs.

Methods: DEs were examined in the peripheral blood and cerebrospinal fluid (CSF) of patients with relapsing-remitting MS (RRMS) compared to healthy controls. Their phenotype and functional properties were characterized, including responses to myelin autoantigens and susceptibility to depletion in a pilot cohort of seven RRMS patients treated with ocrelizumab.

Results: DEs were found at significantly higher frequencies in the peripheral blood of patients with RRMS compared to healthy controls and were further enriched in CSF, where up to 95% expressed CD20, versus ~60% in blood. Furthermore, most of DEs in CSF express CXCR3, indicating involvement of CXCR3-CCL-9, 10 and 11 in their recruiting and maintenance in the CSF of MS patients. Functionally, DEs exhibited robust responses to myelin autoantigens, supporting their relevance in disease. In a pilot cohort of seven RRMS patients, ocrelizumab significantly reduced circulating DE frequencies, confirming their susceptibility to CD20-mediated depletion.

Conclusions: These findings implicate DEs in MS and provide insight into the efficacy of anti-CD20 therapies in a traditionally T cell-driven disease.