Macrophage Dectin-1 mediates Ang II renal injury through neutrophil migration and TGF-β1 secretion

Morus alba L. alleviates influenza viral pneumonia. Evidences of its mechanism of action

BACKGROUND

Viral pneumonia is an infection of the lungs caused by numerous different viruses, which can lead to severe respiratory distress and even life-threatening conditions. In the absence of specific treatments for viral pneumonia, natural traditional medicines offer an alternative in terms of innovative drug therapies. Morus alba L. (common name mulberry leaf) is a Chinese medicine that has been used clinically as an antiviral.

PURPOSE

The therapeutic effect of M. alba on viral pneumonia was investigated along with its mechanism of action.

METHODS

Network pharmacology and molecular docking were used to analyze the mechanism of action of M. alba in the treatment of viral pneumonia. Histology, immunofluorescence, Western blotting, qPCR, and flow cytometry were used to evaluate the protective effect of MLE (the ethanol extract of Morus alba L.) on PR8 (A/Puerto Rico/8/1934 H1N1, a murine lung-adapted influenza A virus strain)-induced viral pneumonia. SiRNA was used to validate the relationship between the therapeutic effects of MLE on viral pneumonia and the target Syk (a crucial non-receptor tyrosine kinase).

RESULTS

MLE alleviated PR8-induced viral pneumonia by reducing inflammatory factor expression in the lungs, decreasing NF-κB pathway activation, slowing oxidative damage in the lungs, and inhibiting lung tissue cell apoptosis. Meanwhile, MLE for viral pneumonia was significantly associated with Syk targets. Notably, knockdown of the Syk gene not only reduced the therapeutic effect of MLE, but also suppressed PR8-induced viral pneumonia.

CONCLUSION

MLE can alleviate PR8-induced viral pneumonia through inhibiting the Dectin-1/Syk pathway.

Rutin resists Aspergillus fumigatus keratitis by activating Nrf2/HO-1 pathway, inhibiting Dectin-1/p-Syk pathway and affecting fungal structures

Fungal keratitis (FK) is a severe vision-threatening eye disease. The fungal invasiveness and excessive inflammatory response contribute to corneal tissue damage. Rutin (RT) possesses anti-inflammatory, antimicrobial, antioxidant, and improved wound-healing characteristics. This study aimed to evaluate antifungal, anti-inflammatory, and therapeutic effects of RT in FK. The results showed that RT exerted antifungal effects by inhibiting fungal growth, altering hyphal morphology, destroying biofilm, and disrupting fungal cellular structures. RT exhibited anti-inflammatory benefits by suppressing the Dectin-1/p-Syk pathway, activating the Nrf2/HO-1 pathway, and decreasing the expression of inflammatory factors in vivo and in vitro. RT demonstrated therapeutic effects by reducing clinical scores, fungal load, macrophage recruitment, and neutrophil activity. In conclusion, RT exhibited anti-inflammatory, antifungal, and therapeutic effects in Aspergillus fumigatus keratitis, and has the potential to become a novel therapeutic strategy for FK.

Laminarin Alleviates Acute Lung Injury Induced by LPS Through Inhibition of M1 Macrophage Polarisation

The lipopolysaccharide-induced acute lung injury (ALI) mouse model is used to simulate human acute respiratory distress syndrome (ARDS), which has a high mortality rate. An imbalance between M1 and M2 macrophages, characterised by an increase in M1 macrophages, was observed in sepsis-induced ALI. We report that laminarin, an active ingredient found in algae, exhibits exceptional performance in a mouse model of sepsis-induced ALI. It ameliorates lung edema, enhances the survival rate of mice and reduces the levels of the inflammatory factors TNF-α and IL-6. Furthermore, laminarin reduced the expression of CD86, which are markers associated with M1 macrophages. Laminarin treatment reduces the secretion of TNF-α and IL-6 in LPS-stimulated macrophages. Laminarin treatment also decreases glucose uptake in LPS-stimulated macrophages. Transcriptome sequencing reveals that genes downregulated in LPS-stimulated macrophages following laminarin treatment are predominantly enriched in the HIF-1α signalling pathway. Experimental validation confirms that laminarin treatment of LPS-stimulated macrophages reduces the expression of HIF-1α and significantly decreases the expression of related indicators ROS and NLRP3. After using siRNA to knock down HIF-1α in RAW264.7 cells, the inhibitory effect of laminarin on LPS-induced M1 polarisation of macrophages is abolished. This suggests that laminarin may potentially inhibit macrophage polarisation towards the M1 phenotype by downregulating the HIF-1α signal. In conclusion, the data presented in our study demonstrate that laminarin can effectively reduce M1 macrophage polarisation by downregulating HIF-1α signalling. This makes it a novel candidate drug for the treatment of LPS-induced ALI.

Tumor‑associated macrophages activated in the tumor environment of hepatocellular carcinoma: Characterization and treatment (Review)

Hepatocellular carcinoma (HCC) tissue is rich in dendritic cells, T cells, B cells, macrophages, natural killer cells and cellular stroma. Together they form the tumor microenvironment (TME), which is also rich in numerous cytokines. Tumor‑associated macrophages (TAMs) are involved in the regulation of tumor development. TAMs in HCC receive stimuli in different directions, polarize in different directions and release different cytokines to regulate the development of HCC. TAMs are mostly divided into two cell phenotypes: M1 and M2. M1 TAMs secrete pro‑inflammatory mediators, and M2 TAMs secrete a variety of anti‑inflammatory and pro‑tumorigenic substances. The TAM polarization in HCC tumors is M2. Both direct and indirect methods for TAMs to regulate the development of HCC are discussed. TAMs indirectly support HCC development by promoting peripheral angiogenesis and regulating the immune microenvironment of the TME. In terms of the direct regulation between TAMs and HCC cells, the present review mainly focuses on the molecular mechanism. TAMs are involved in both the proliferation and apoptosis of HCC cells to regulate the quantitative changes of HCC, and stimulate the related invasive migratory ability and cell stemness of HCC cells. The present review aims to identify immunotherapeutic options based on the mechanisms of TAMs in the TME of HCC.

DACT2 modulates atrial fibrillation through TGF/β and Wnt signaling pathways

Atrial fibrillation (AF) is a common cardiac arrhythmia that seriously affects the quality of life of patients. Effective treatment and prevention are important to control the morbidity and mortality of AF. It has been found that cardiac fibrosis promotes the onset and progression of AF. It is now known that transforming growth factor β (TGF-β), an important fibrotic cytokine, plays an important role in cardiac fibrosis by inducing myofibroblast activation via the activation of classical (SMAD-based) and non-classical (non-SMAD-based) signaling pathways. In addition, specific activation of the Wnt/β-catenin pathway has been shown to promote the transformation of fibroblasts into myofibroblasts. In recent years, a new family of proteins, namely Disheveled-associated antagonist of beta-catenin (DACT) 2, can affect the Wnt/β-catenin and TGF-β signaling pathways by regulating the phosphorylation levels of these target proteins, which in turn affects the progression of fibrosis. The present study focuses on the effect of DACT2-guided β-catenin on atrial fibrosis. It is expected that the summarized information can be helpful in the treatment of AF.

Renal Fibrosis: SIRT1 Still of Value

Chronic kidney disease (CKD) is a major global health concern. Renal fibrosis, a prevalent outcome regardless of the initial cause, ultimately leads to end-stage renal disease. Glomerulosclerosis and renal interstitial fibrosis are the primary pathological features. Preventing and slowing renal fibrosis are considered effective strategies for delaying CKD progression. However, effective treatments are lacking. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase belonging to class III histone deacetylases, is implicated in the physiological regulation and protection of the kidney and is susceptible to a diverse array of pathological influences, as demonstrated in previous studies. Interestingly, controversial conclusions have emerged as research has progressed. This review provides a comprehensive summary of the current understanding and advancements in the field; specifically, the biological roles and mechanisms of SIRT1 in regulating renal fibrosis progression. These include aspects such as lipid metabolism, epithelial-mesenchymal transition, oxidative stress, aging, inflammation, and autophagy. This manuscript explores the potential of SIRT1 as a therapeutic target for renal fibrosis and offers new perspectives on treatment approaches and prognostic assessments.

Dectin-1 aggravates neutrophil inflammation through caspase-11/4-mediated macrophage pyroptosis in asthma

BACKGROUND

The pattern recognition receptor Dectin-1 was initially discovered to play a pivotal role in mediating pulmonary antifungal immunity and promoting neutrophil-driven inflammation. Recent studies have revealed that Dectin-1 is overexpressed in asthma, but the specific mechanism remains elusive. Additionally, Dectin-1 has been implicated in promoting pyroptosis, a hallmark of severe asthma airway inflammation. Nevertheless, the involvement of the non-classical pyroptosis signal caspase-11/4 and its upstream regulatory mechanisms in asthma has not been completely explored.

METHODS

House dust mite (HDM)-induced mice was treated with Dectin-1 agonist Curdlan, Dectin-1 inhibitor Laminarin, and caspase-11 inhibitor wedelolactone separately. Subsequently, inflammatory cells in bronchoalveolar lavage fluid (BALF) were analyzed. Western blotting was performed to measure the protein expression of caspase-11 and gasdermin D (GSDMD). Cell pyroptosis and the expression of chemokine were detected in vitro. The correlation between Dectin-1 expression, pyroptosis factors and neutrophils in the induced sputum of asthma patients was analyzed.

RESULTS

Curdlan appeared to exacerbate neutrophil airway inflammation in asthmatic mice, whereas wedelolactone effectively alleviated airway inflammation aggravated by Curdlan. Moreover, Curdlan enhanced the release of caspase-11 activation fragments and N-terminal fragments of gasdermin D (GSDMD-N) stimulated by HDM both in vivo or in vitro. In mouse alveolar macrophages (MH-S cells), Curdlan/HDM stimulation resulted in vacuolar degeneration and elevated lactate dehydrogenase (LDH) release. In addition, there was an upregulation of neutrophil chemokines CXCL1, CXCL3, CXCL5 and their receptor CXCR2, which was suppressed by wedelolactone. In asthma patients, a positive correlation was observed between the expression of Dectin-1 on macrophages and caspase-4 (the human homology of caspase-11), and the proportion of neutrophils in induced sputum.

CONCLUSION

Dectin-1 activation in asthma induced caspase-11/4 mediated macrophage pyroptosis, which subsequently stimulated the secretion of chemokines, leading to the exacerbation of airway neutrophil inflammation.

Knockdown of lncRNA MALAT1 attenuates renal interstitial fibrosis through miR-124-3p/ITGB1 axis

Renal interstitial fibrosis (RIF) considered the primary irreversible cause of chronic kidney disease. Recently, accumulating studies demonstrated that lncRNAs play an important role in the pathogenesis of RIF. However, the underlying exact mechanism of lncRNA MALAT1 in RIF remains barely known. Here, the aim of our study was to investigate the dysregulate expression of lncRNA MALAT1 in TGF-β1 treated HK2/NRK-49F cells and unilateral ureteral obstruction (UUO) mice model, defining its effects on HK2/NRK-49F cells and UUO mice fibrosis process through the miR-124-3p/ITGB1 signaling axis. It was found that lncRNA MALAT1 and ITGB1 was significantly overexpression, while miR-124-3p was downregulated in HK2/NRK-49F cells induced by TGF-β1 and in UUO mice model. Moreover, knockdown of lncRNA MALAT1 remarkably downregulated the proteins level of fibrosis-related markers, ITGB1, and upregulated the expression of epithelial marker E-cadherin. Consistently, mechanistic studies showed that miR-124-3p can directly binds to lncRNA MALAT1 and ITGB1. And the protect effect of Len-sh-MALAT1 on fibrosis related protein levels could be partially reversed by co-transfected with inhibitor-miR-124-3p. Moreover, the expression trend of LncRNA MALAT1/miR-124-3p/ITGB1 in renal tissues of patients with obstructive nephropathy (ON) was consistent with the results of cell and animal experiments. Taken together, these results indicated that lncRNA MALAT1 could promote RIF process in vitro and in vivo via the miR-124-3p/ITGB1 signaling pathway. These findings suggest a new regulatory pathway involving lncRNA MALAT1, which probably serves as a potential therapeutic target for RIF.