Identification of a novel cuproptosis-related gene signature for rheumatoid arthritis-A prospective study.

BACKGROUND: Rheumatoid arthritis (RA) is a multifactorial systemic autoimmune disease characterized by ongoing synovial inflammation, leading to the degradation of cartilage. Cuproptosis, as a newly characterized form of cell death, may influence RA progression by regulating immune cells and chondrocytes. This study sets out to identify the hub cuproptosis-related gene (CRG) associated with the pathogenesis of RA. METHODS: A series of bioinformatic analyses were performed to evaluate the expression score of CRGs and the immune infiltration landscape between RA and normal samples. The hub gene was screened through the correlation analysis of CRGs, and the interaction network between the hub gene and transcription factors (TFs) was constructed. Finally, the hub gene was validated through quantitative real-time polymerase chain reaction (qRT-PCR) of patient samples and cell experiments. RESULTS: Drolipoamide S-acetyltransferase (DLAT) was screened as the hub gene. Correlation analysis between the hub gene and immune microenvironment demonstrated that DLAT had the highest correlation with T follicular helper cells. Eight pairs of DLAT-TF interaction networks were constructed. Single-cell sequencing showed that CRGs were highly expressed in RA chondrocytes, and chondrocytes could be classified into three different subsets. qRT-PCR was used to validate the above results. Dlat knockdown in immortalized human chondrocytes led to significantly improved mitochondrial membrane potentials and reduced levels of intracellular reactive oxygen species (ROS), mitochondrial ROS and apoptosis. CONCLUSIONS: This study rudimentarily demonstrates the correlation between CRGs and immune cell infiltration in RA. The biomarker DLAT may provide comprehensive insights into the pathogenesis and drug targets of RA.

SAMHD1 Attenuates Acute Inflammation by Maintaining Mitochondrial Function in Macrophages via Interaction with VDAC1.

Over-activation of Toll-like receptor 4 (TLR4) is the key mechanism in Gram-negative bacterial infection-induced sepsis. SAM and HD domain-containing deoxynucleoside triphosphate triphosphohydrolase 1 (SAMHD1) inhibits multiple viruses, but whether it plays a role during bacterial invasion remains unelucidated. Monocyte-macrophage specific Samhd1 knockout (Samhd1-/-) mice and Samhd1-/- macrophage cell line RAW264.7 were constructed and used as research models to evaluate the role of SAMHD1 in TLR4-activated inflammation. In vivo, LPS-challenged Samhd1-/- mice showed higher serum inflammatory factors, accompanied with more severe inflammation infiltration and lower survival rate. In vitro, Samhd1-/- peritoneal macrophages had more activated TLR4 pathway upon LPS-stimulation, accompanied with mitochondrial depolarization and dysfunction and a higher tendency to be M1-polarized. These results could be rescued by overexpressing full-length wild-type SAMHD1 or its phospho-mimetic T634D mutant into Samhd1-/- RAW264.7 cells, whereas the mutants, dNTP hydrolase-function-deprived H238A and phospho-ablative T634A, did not exert the same effect. Lastly, co-IP and immunofluorescence assays confirmed that SAMHD1 interacted with an outer mitochondrial membrane-localized protein, voltage-dependent anion channel-1 (VDAC1). SAMHD1 inhibits TLR4-induced acute inflammation and M1 polarization of macrophages by interacting with VDAC1 and maintaining mitochondria function, which outlines a novel regulatory mechanism of TLR signaling upon LPS stimulation.

Effect of magnetic field coupled magnetic biochar on membrane bioreactor efficiency, membrane fouling mitigation and microbial communities.

The excitation by magnetic field was established to mitigate the membrane fouling of magnetic biochar (MB)-supplemented membrane bioreactor (MBR) in this study. The results showed that the transmembrane pressure (TMP) increase rates decreased by about 8 % after introducing the magnetic field compared with the magnetic biochar-MBR (MB-MBR). Membrane characterization suggested that the flocs in the magnetic field-magnetic biochar-MBR (MF-MB-MBR) formed a highly permeable developed cake layer, and a fluffier and more porous deposited layer on membrane surface, which minimized fouling clogging of the membrane pores. Further mechanistic investigation revealed that the decrease in contact angle of fouled membrane surface in MF-MB-MBR, i.e. an enhanced membrane hydrophilicity, is considered important for forming highly permeable layers. Additionally, the magnetic field was demonstrated to have a positive effect on the improvement of the magneto-biological effect, the enhancement of charge neutralization and adsorption bridging between sludge and magnetic biochar, and the reduction of formation of extracellular polymeric substances (EPSs), which all yielded sludge flocs with a large pore structure conducive to form a fluffy and porous deposited layer in the membrane surface. Furthermore, high-throughput sequencing analysis revealed that the magnetic field also led to a reduction in microbial diversity, and that it promoted the enrichment of specific functional microbial communities (e.g. Bacteroidetes and Firmicutes) playing an important role in mitigating membrane fouling. Taken together, this study of magnetic field-enhanced magnetic biochar for MBR membrane fouling mitigation provides insights important new ideas for more effective and sustainable operation strategies.

Increased glucose metabolism in TAMs fuels O-GlcNAcylation of lysosomal Cathepsin B to promote cancer metastasis and chemoresistance.

How glucose metabolism remodels pro-tumor functions of tumor-associated macrophages (TAMs) needs further investigation. Here we show that M2-like TAMs bear the highest individual capacity to take up intratumoral glucose. Their increased glucose uptake fuels hexosamine biosynthetic pathway-dependent O-GlcNAcylation to promote cancer metastasis and chemoresistance. Glucose metabolism promotes O-GlcNAcylation of the lysosome-encapsulated protease Cathepsin B at serine 210, mediated by lysosome-localized O-GlcNAc transferase (OGT), elevating mature Cathepsin B in macrophages and its secretion in the tumor microenvironment (TME). Loss of OGT in macrophages reduces O-GlcNAcylation and mature Cathepsin B in the TME and disrupts cancer metastasis and chemoresistance. Human TAMs with high OGT are positively correlated with Cathepsin B expression, and both levels predict chemotherapy response and prognosis of individuals with cancer. Our study reports the biological and potential clinical significance of glucose metabolism in tumor-promoting TAMs and reveals insights into the underlying mechanisms.

Functional study on galactose-specific lectin 3 from tumor-associated macrophage based on single-cell sequencing / 中国肿瘤生物治疗杂志

@#[摘 要] 目的：从肿瘤相关巨噬细胞（TAM）在化疗前后的表型变化入手，寻找通过调控肿瘤免疫微环境（TIME）从而影响肿瘤治疗效果和预后的功能分子。方法：利用欧洲核苷酸数据库（ENA）的PRJEB45598数据集，分析进展期胃癌患者化疗前后活检肿瘤组织单细胞测序数据，采用主成分分析（PCA）和一致流形近似与投影（UMAP）降维，获得31个亚群细胞，并进一步进行TAM亚型分析、差异基因筛选，寻找化疗后M2型TAM中高表达的基因。通过黑色素瘤B16-F10细胞皮下移植瘤模型验证化疗前后特定基因mRNA和蛋白水平表达变化，并通过Incucyte体外分析该蛋白是否调控化疗药物诱导的肿瘤细胞死亡。结果：聚焦单细胞测序数据中M2型TAM的特征表达基因，发现半乳糖凝集素3（LGALS3）在胃癌化疗后mRNA水平显著升高（P<0.01），在多种肿瘤中LGALS3高表达且与患者生存期呈负相关（P<0.05或P<0.01）。黑色素瘤B16-F10细胞移植瘤模型中，LGALS3在M2型TAM中高表达（P<0.01），且奥沙利铂化疗后表达进一步升高（P<0.05）。体外对肿瘤细胞给予重组LGALS3蛋白可抑制化疗药物奥沙利铂诱导的肿瘤细胞死亡（P<0.01）。结论：奥沙利铂化疗后的M2型TAM通过合成和分泌LGALS3促进黑色素瘤细胞的化疗抵抗，因此通过免疫治疗的方法靶向LGALS3分子可能有效提高肿瘤的治疗效果。

Epigenetic regulation of polarization and functional reprogramming of tumor-associated macrophages：a novel strategy of cancer therapy / 中国肿瘤生物治疗杂志

@#肿瘤相关巨噬细胞（TAM）在肿瘤发展、转移和治疗抵抗中扮演了关键角色。TAM包含两种可相互极化的类型：促炎、抑制肿瘤生长的M1型和抑炎、促进肿瘤进展的M2型。表观遗传机制在肿瘤微环境对TAM的功能塑造中的作用十分独特，主要介导极化相关信号通路、细胞因子、代谢酶、关键转录因子和MHC及其调控因子等功能基因的转录或转录后调控，从而决定TAM的极化状态和功能。因此，从表观调控入手抑制M2极化、促进M1极化，进而引起TAM功能重塑，已逐渐成为肿瘤治疗的一个新兴策略。通过鉴定TAM特异性及关键表观调节机制、开发靶向TAM的新型表观药物递送系统、有效联合其他抗肿瘤疗法等方式，可进一步提高基于表观遗传调控的靶向巨噬细胞治疗的特异性，降低不良反应，实现更理想的抗肿瘤效果。