Molecular immunology最新文献

Objective

Dihydroartemisinin (DHA) plays a very important role in various diseases. However, the precise involvement of DHA in systemic lupus erythematosus (SLE), relation to the equilibrium between M1 and M2 cells, remains uncertain. Therefore, we aimed to investigate the role of DHA in SLE and its effect on the M1/M2 cells balance.

Methods

SLE mice model was established by pristane induction. Flow cytometry was employed to measure the abundance of M1 and M2 cells within the peripheral blood of individuals diagnosed with SLE. The concentrations of various cytokines, namely TNF-α, IL-1β, IL-4, IL-6, and IL-10, within the serum of SLE patients or SLE mice were assessed via ELISA. Immunofluorescence staining was utilized to detect the deposition of IgG and complement C3 in renal tissues of the mice. We conducted immunohistochemistry analysis to assess the expression levels of Collagen-I, a collagen protein, and α-SMA, a fibrosis marker protein, in the renal tissues of mice. Hematoxylin-eosin staining, Masson’s trichrome staining, and Periodic acid Schiff staining were used to examine histological alterations. In this study, we employed qPCR and western blot techniques to assess the expression levels of key molecular markers, namely CD80 and CD86 for M1 cells, as well as CD206 and Arg-1 for M2 cells, within kidney tissue. Additionally, we investigated the involvement of the MAPK signaling pathway. The Venny 2.1 online software tool was employed to identify shared drug-disease targets, and subsequently, the Cytoscape 3.9.2 software was utilized to construct the “disease-target-ingredient” network diagram. Protein-protein interactions of the target proteins were analyzed using the String database, and the network proteins underwent enrichment analysis for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways.

Results

The results showed that an increase in M1 cells and a decrease in M2 cells within the peripheral blood of individuals diagnosed with SLE. Further analysis revealed that prednisone (PDN) combined with DHA can alleviate kidney damage and regulate the balance of M1 and M2 cells in both glomerular mesangial cells (GMC) and kidney. The MAPK signaling pathway was found to be involved in SLE kidney damage and M1/M2 balance in the kidney. Furthermore, PDN and/or DHA were found to inhibit the MAPK signaling pathway in GMC and kidney.

Conclusion

We demonstrated that PDN combined with DHA attenuates SLE by regulating M1/M2 balance through MAPK signaling pathway. These findings propose that the combination of PDN and DHA could serve as a promising therapeutic strategy for SLE, as it has the potential to mitigate kidney damage and reinstate the equilibrium of M1 and M2 cells.

Mammalian reovirus (MRV) is a non-enveloped, gene segmented double-stranded RNA (dsRNA) virus. It is an important zoonotic pathogen that infects many mammals and vertebrates that act as natural hosts and causes respiratory and digestive tract diseases. Studies have reported that RIG-I and MDA5 in the innate immune cytoplasmic RNA-sensing RIG-like receptor (RLR) signaling pathway can recognize dsRNA from MRV and promote antiviral type I interferon (IFN) responses. However, the mechanism by which many MRV-encoded proteins evade the host innate immune response remains unclear. Here, we show that exogenous μ1 protein promoted the proliferation of MRV in vitro, while knockdown of MRV μ1 protein expression by shRNA could impair MRV proliferation. Specifically, μ1 protein inhibited MRV or poly(I:C)-induced IFN-β expression, and attenuated RIG-I/MDA5-mediated signaling axis transduction during MRV infection. Importantly, we found that μ1 protein significantly decreased IFN-β mRNA expression induced by MDA5, RIG-I, MAVS, TBK1, IRF3(5D), and degraded the protein expression of exogenous MDA5, RIG-I, MAVS, TBK1 and IRF3 via the proteasomal and lysosomal pathways. Additionally, we show that μ1 protein can physically interact with MDA5, RIG-I, MAVS, TBK1, and IRF3 and attenuate the RIG-I/MDA5-mediated signaling cascades by blocking the phosphorylation and nuclear translocation of IRF3. In conclusion, our findings reveal that MRV outer capsid protein μ1 is a key factor in antagonizing RLRs signaling cascades and provide new strategies for effective prevention and treatment of MRV infection.

Background

Endothelial cell injury and dysfunction lead to cholesterol and lipid accumulation and atherosclerotic plaque formation in the arterial wall during atherosclerosis (AS) progression, Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), a DNA methylation regulator, was strongly upregulated in atherosclerotic plaque lesions in mice. This study aimed to investigate the precise biological functions and regulatory mechanisms of UHRF1 on endothelial dysfunction during AS development.

Methods

UHRF1 levels in the atherosclerotic plaque tissues and normal arterial intima from AS patients were tested with Western blot analysis and immunohistochemistry assays. Human umbilical vein endothelial cells (HUVECs) were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce an injury model and then transfected with short hairpin RNA targeting UHRF1 (sh-UHRF1). Cell proliferation, migration, apoptosis, the levels of inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and the protein levels adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured. Moreover, co-immunoprecipitation assay was used to determine the interactions between UHRF1 and DNA methyltransferases 1 (DNMT1), As well as mothers against DPP homolog 7 (SMAD7) and yes-associated protein 1 (YAP1). SMAD7 promoter methylation was examined with methylation-specific PCR. In addition, we established an AS mouse model to determine the in vivo effects of UHRF1 on AS progression.

Results

UHRF1 was upregulated in atherosclerotic plaque tissues and ox-LDL-treated HUVECs. UHRF1 knockdown mitigated ox-LDL-induced proliferation and migration inhibition, apoptosis and the production of TNF-α, IL-6, VCAM-1, and ICAM-1 in HUVECs. Mechanistically, UHRF1 promoted DNMT1-mediated SMAD7 promoter methylation and inhibited its expression. SMAD7 knockdown abolished the protective effects of UHRF1 knockdown on ox-LDL-induced HUVEC injury. Moreover, SMAD7 interacted with YAP1 and inhibited YAP1 expression by promoting YAP1 protein ubiquitination-independent degradation in HUVECs. YAP1 overexpression abrogated SMAD7 overexpression-mediated protective effects on ox-LDL-induced HUVEC injury. Finally, UHRF1 knockdown alleviated atherosclerotic plaque deposition and arterial lesions in AS mice.

Conclusion

UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates AS progression in mice by regulating the SMAD7/YAP1 axis

Sepsis is a systemic inflammatory response syndrome caused by trauma or infection, which can lead to multiple organ dysfunction. In severe cases, sepsis can also progress to septic shock and even death. Effective treatments for sepsis are still under development. This study aimed to determine if targeting the PI3K/Akt signaling with CAL-101, a PI3K p110δ inhibitor, could alleviate lipopolysaccharide (LPS)-induced sepsis and contribute to immune tolerance. Our findings indicated that CAL-101 treatment improved survival rates and alleviated the progression of LPS-induced sepsis. Compared to antibiotics, CAL-101 not only restored the Th17/regulatory T cells (Treg) balance but also enhanced Treg cell function. Additionally, CAL-101 promoted type 2 macrophage (M2) polarization, inhibited TNF-α secretion, and increased IL-10 secretion. Moreover, CAL-101 treatment reduced pyroptosis in peritoneal macrophages by inhibiting caspase-1/gasdermin D (GSDMD) activation. This study provides a mechanistic basis for future clinical exploration of targeted therapeutics and immunomodulatory strategies in the treatment of sepsis.

The pathogenesis of neuropathic pain (NP) is complex, and there are various pathological processes. Previous studies have suggested that lncRNA PCAT19 is abnormally expressed in NP conduction and affects the occurrence and development of pain. The aim of this study is to analyze the role and mechanism of PCAT19 in NP induced by chronic compressive nerve injury (CCI) in mice. In this study, C57BL/6 mice were applied to establish the CCI model. sh-PCAT19 was intrathecally injected once a day for 5 consecutive days from the second day after surgery. We discovered that PCat19 level was gradually up-regulated with the passage of modeling time. Downregulation of Iba-1-positive expression, M1/M2 ratio of microglia, and pro-inflammatory factors in the spinal cords of CCI-mice after PCat19 knock-downed was observed. Mechanically, the expression of miR-378a-3p was negatively correlated with KDM3A and PCat19. Deletion of KDM3A prevented H3K9me2 demethylation of BDNF promoter and suppressed BDNF expression. Further, KDM3A promotes CCI-induced neuroinflammation and microglia activation by mediating Brain-derived neurotrophic factor (BDNF) demethylation. Together, the results suggest that PCat19 may be involved in the development of NP and that PCat19 shRNA injection can attenuate microglia-induced neuroinflammation by blocking KDM3A-mediated demethylation of BDNF and BDNF release.

Macrophage polarization towards the M1 phenotype under bacterial product-related exposure (LPS) requires a rapid change in gene expression patterns and cytokine production along with a metabolic rewiring. Metabolic pathways and redox reactions are such tightly connected, giving rise to an area of research referred to as immunometabolism. A role in this context has been paid to the master redox-sensitive regulator Nuclear factor erythroid 2-related factor 2 (Nrf2) and to the 5’-ectonucleotidase CD73, a marker related to macrophage metabolism rearrangement under pro-inflammatory conditions. In this light, a cell model of LPS-stimulated macrophages has been established and nine 4,7-dihydro-4-ethylpyrazolo[l,5-a]pyrimidin-7-ones with a potential anti-inflammatory effect have been administered. Our data highlight that two selected compounds (namely, 5 and 8) inhibit the LPS-induced Nrf2 nuclear translocation and ameliorate the activity rate of the antioxidant enzyme catalase. Additionally, the pyridine-containing compound (8) promotes the shift from the pro-inflammatory immunophenotype M1 to the pro-resolving M2 one, by downregulating CD80 and iNOS and by enhancing CD163 and TGFβ1 expression. Most importantly, CD73 is modulated by these compounds as well as the lactate production. Our data demonstrate that pyrazolo[l,5-a]pyrimidine derivatives are effective as anti-inflammatory compounds. Furthermore, these pyrazolo[l,5-a]pyrimidines exert their action via CD73-related signaling and modulation of cell metabolism of activated macrophages.

Peroxiredoxins are antioxidant proteins that detoxify peroxynitrite, hydrogen peroxide, and organic hydroperoxides, impacting various physiological processes such as immune responses, apoptosis, cellular homeostasis, and so on. In the present study, we identified and characterized peroxiredoxin 1 from Antheraea pernyi (thereafter designated as ApPrx-1) that encodes a predicted 195 amino acid residue protein with a 21.8 kDa molecular weight. Quantitative real-time PCR analysis revealed that the mRNA level of ApPrx-1 was highest in the hemocyte, fat body, and midgut. Immune-challenged larval fat bodies and hemocytes showed increased ApPrx-1 transcript. Moreover, ApPrx-1 expression was induced in hemocytes and the whole body of A. pernyi following exogenous H₂O₂ administration. A DNA cleavage assay performed using recombinant ApPrx-1 protein showed that rApPrx-1 protein manifests the ability to protect supercoiled DNA damage from oxidative stress. To test the rApPrx-1 protein antioxidant activity, the ability of the rApPrx-1 protein to remove H₂O₂ was assessed in vitro using rApPrx-1 protein and DTT, while BSA + DDT served as a control group. The results revealed that ApPrx-1 can efficiently remove H₂O₂ in vitro. In the loss of function analysis, we found that ApPrx-1 significantly increased the levels of H₂O₂ in ApPrx-1-depleted larvae compared to the control group. We also found a significantly lower survival rate in the larvae in which ApPrx-1 was knocked down. Interestingly, the antibacterial activity was significantly higher in the ApPrx-1 depleted larvae, compared to the control. Collectively, evidence strongly suggests that ApPrx-1 may regulate physiological activities and provides a reference for further studies to validate the utility of the key genes involved in reliving oxidative stress conditions and regulating the immune responses of insects.

Liver diseases caused by viral infections, alcoholism, drugs, or chemical poisons are a significant health problem: Liver diseases are a leading contributor to mortality, with approximately 2 million deaths per year worldwide. Liver fibrosis, as a common liver disease characterized by excessive collagen deposition, is associated with high morbidity and mortality, and there is no effective treatment. Numerous studies have shown that the accumulation of mast cells (MCs) in the liver is closely associated with liver injury caused by a variety of factors. This study investigated the relationship between MCs and carbon tetrachloride (CCl4)-induced liver fibrosis in rats and the effects of the MC stabilizers sodium cromoglycate (SGC) and ketotifen (KET) on CCl4-induced liver fibrosis. The results showed that MCs were recruited or activated during CCl4-induced liver fibrosis. Coadministration of SCG or KET alleviated the liver fibrosis by decreasing SCF/c-kit expression, inhibiting the TGF-β1/Smad2/3 pathway, depressing the HIF-1a/VEGF pathway, activating Nrf2/HO-1 pathway, and increasing the hepatic levels of GSH, GSH-Px, and GR, thereby reducing hepatic oxidative stress. Collectively, recruitment or activation of MCs is linked to liver fibrosis and the stabilization of MCs may provide a new approach to the prevention of liver fibrosis.

Neuroplastin, a paralog of CD147/Basigin, is known as a neuronal cell adhesion molecule and as an auxiliary subunit of plasma membrane calcium ATPases in both neurons and adaptive immune cells. Recently, an interesting study by Ren et al. (2022) provided evidence for an important role of neuroplastin in macrophages during bacterial infection. Here, we critically discuss one aspect of this study, the assignment of this role to Np65 as one of two prominent splice variants of neuroplastin.

Peritoneal B cells can be divided into B1 cells (CD11b⁺CD19⁺) and B2 cells (CD11b^-CD19⁺) based on CD11b expression. B1 cells play a crucial role in the innate immune response by producing natural antibodies and cytokines. B2 cells share similar traits with B1 cells, influenced by the peritoneal environment. However, the response of both B1 and B2 cells to the same stimuli in the peritoneum remains uncertain. We isolated peritoneal B1 and B2 cells from mice and assessed differences in Interleukin-10(IL-10) secretion, apoptosis, and surface molecule expression following exposure to LPS and Interleukin-21(IL-21). Our findings indicate that B1 cells are potent IL-10 producers, possessing surface molecules with an IgM^hiCD43⁺CD21^low profile, and exhibit a propensity for apoptosis in vitro. Conversely, B2 cells exhibit lower IL-10 production and surface markers characterized as IgM^lowCD43^-CD21^hi, indicative of some resistance to apoptosis. LPS stimulates MAPK phosphorylation in B1 and B2 cells, causing IL-10 production. Furthermore, LPS inhibits peritoneal B2 cell apoptosis by enhancing Bcl-xL expression. Conversely, IL-21 has no impact on IL-10 production in these cells. Nevertheless, impeding STAT3 phosphorylation permits IL-21 to increase IL-10 production in peritoneal B cells. Moreover, IL-21 significantly raises apoptosis levels in these cells, a process independent of STAT3 phosphorylation and possibly linked to reduced Bcl-xL expression. This study elucidates the distinct functional and response profiles of B1 and B2 cells in the peritoneum to stimuli like LPS and IL-21, highlighting their differential roles in immunological responses and B cell diversity.