Correlation between macrophage chemotaxis and disease severity in patients with knee osteoarthritis / 中国骨伤

OBJECTIVE@#To investigate the enhancement of macrophage chemotaxis in patients with knee osteoarthritis (KOA) and its correlation with the disease severity.@*METHODS@#Eighty patients with KOA admitted from July 2019 to June 2022 were enrolled as the observation group and divided into 29 cases of moderate group, 30 cases of severe group and 21 cases of extremely severe group. At the same time, 30 healthy subjects were included as the control group. The gene expressions of NF-κB, CXC chemokine receptor 7 (CXCR7) and CXC chemokine ligand 12 (CXCL12) in macrophages of each group were analyzed. Visual analogue scale(VAS) was used to evaluate the degree of joint pain. Joint function was evaluated by knee Joint Society Scoring system(KSS). Finally, data analysis was carried out.@*RESULTS@#The expression levels of NF-κB, CXCR7 and CXCL12 in moderate group, severe group and extreme recombination group were higher than those in control group. The VAS, the expression of NF-κB, CXCR7 and CXCL12 in the severe group and the extreme recombination group were higher than those in the moderate group, whereas KSS was lower than that in the moderate group. The VAS, expression levels of NF-κB, CXCR7 and CXCL12 in the extremely severe group were higher than those in the severe group, and KSS was lower than that in the severe group (all P<0.01). The expression levels of NF-κB, CXCR7 and CXCL12 in macrophages were positively correlated with VAS score, but negatively correlated with KSS(all P<0.01). The expression levels of NF-κB, CXCR7 and CXCL12 in macrophages were positively correlated with the severity of disease. After excluding the influence of traditional factors (gender, age and disease duration), multiple linear regression analysis further showed that the expression levels of NF-κB, CXCR7 and CXCL12 were still positively correlated with the severity of disease(all P<0.01).@*CONCLUSION@#The chemotaxis of macrophages in patients with KOA increased with the aggravation of the disease, and was related to the degree of pain and function impairment.

tlpA gene expression is required for arginine and bicarbonate chemotaxis in Helicobacter pylori

About half of the human population is infected with Helicobacter pylori, a bacterium causing gastritis, peptic ulcer and progression to gastric cancer. Chemotaxis and flagellar motility are required for colonization and persistence of H. pylori in the gastric mucus layer. It is not completely clear which chemical gradients are used by H. pylori to maintain its position. TlpA, a chemotaxis receptor for arginine/ bicarbonate, has been identified. This study aimed to find out whether tlpA gene expression is required for the chemotactic response to arginine/bicarbonate. Wild-type motile H. pylori ATCC 700392 and H. pylori ATCC 43504, a strain having an interrupted tlpA gene, were used. Also, a tlpA-knockout mutant of H. pylori 700392 (H. pylori 700-tlpA::cat) was produced by homologous recombination. Expression of tlpA was assessed by a Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assay. Chemotaxis was measured as a Relative Chemotaxis Response (RCR) by a modified capillary assay. H. pylori 700392 presented chemotaxis to arginine and sodium bicarbonate. H. pylori 700-tlpA::cat showed neither tlpA gene expression nor chemotaxis towards arginine and bicarbonate. Besides confirming that TlpA is a chemotactic receptor for arginine/bicarbonate in H. pylori, this study showed that tlpA gene expression is required for arginine/bicarbonate chemotaxis.

Chemotaxis and flagellar genes of Chromobacterium violaceum

The availability of the complete genome of the Gram-negative beta-proteobacterium Chromobacterium violaceum has increasingly impacted our understanding of this microorganism. This review focuses on the genomic organization and structural analysis of the deduced proteins of the chemosensory adaptation system of C. violaceum. C. violaceum has multiple homologues of most chemotaxis genes, organized mostly in clusters in the bacterial genome. We found at least 67 genes, distributed in 10 gene clusters, involved in the chemotaxis of C. violaceum. A close examination of the chemoreceptors methyl-accepting chemotaxis proteins (MCPs), and the deduced sequences of the members of the two-component signaling system revealed canonical motifs, described as essential for the function of the deduced proteins. The chemoreceptors found in C. violaceum include the complete repertoire of such genes described in bacteria, designated as tsr, tar, trg, and tap; 41 MCP loci were found in the C. violaceum genome. Also, the C. violaceum genome includes a large repertoire of the proteins of the chemosensory transducer system. Multiple homologues of bacterial chemotaxis genes, including CheA, CheB, CheD, CheR, CheV, CheY, CheZ, and CheW, were found in the C. violaceum genome