Thiosulfinate-Enriched Allium sativum Extract Exhibits Differential Effects between Healthy and Sepsis Patients: The Implication of HIF-1α

Effects of aged garlic extract on experimental periodontitis in mice

Aged garlic extract (AGE) has been reported to exert anti-inflammatory effects. AGE has been recently found to reduce the inflammatory symptoms of periodontitis, a widespread chronic inflammatory disease caused by oral bacterial infection. However, the mechanisms underlying these effects remain unclear. In the present study, it was aimed to determine the effects of AGE on experimental periodontitis and the related inflammatory factors. AGE (2 g/kg/day) was orally administered to 15 mice during the experimental period, while a control group consisted of 15 mice that received pure water. A total of 3 days after initiation of administration, the left maxillary second molar was ligated with a 5-0 silk thread for 7 days. Blood biochemical tests were performed to monitor the systemic effects of AGE. Alveolar bone loss was measured morphometrically using a stereomicroscope, and reverse transcription-quantitative PCR was performed to assay mRNAs of proinflammatory cytokines in gingival tissues. A histological survey was also performed to identify osteoclasts in periodontitis lesions (five mice per group). The total protein and albumin levels showed no significant differences between the AGE and control groups. However, ligation-induced bone resorption was lower in the AGE group than in the control group (P=0.01). Additionally, ligature increased the mRNA expression of inflammatory cytokines, whereas AGE administration tended to suppress them. Remarkably, tumor necrosis factor gene expression was significantly suppressed (P=0.04). The number of osteoclasts in periodontitis lesions was reduced in the AGE-treated group. These results indicate that AGE prevents alveolar bone loss by suppressing the inflammatory responses related to osteoclast differentiation in the periodontal tissue. Further research is needed to elucidate the role of AGE in reducing inflammatory bone resorption.

Multi-omics analysis reveals that low cathepsin S expression aggravates sepsis progression and worse prognosis via inducing monocyte polarization

Background

Monocytes represent a vital cellular subpopulation in the peripheral blood, crucial in the progression of sepsis. Nonetheless, the prognostic role and precise function of monocytes in sepsis are still inadequately understood.

Methods

Single-cell transcriptomic sequencing and bioinformatics analysis were performed on peripheral blood samples from septic patients to identify key molecules in cell subsets. Subsequently, the expression pattern of this molecule was validated through diverse biological experiments, encompassing quantitative RT-PCR, western blotting, and immunofluorescence. Finally, the functionality of this molecule was evaluated using its specific agonist.

Results

A total of 22 monocytes-related biomarkers were identified from single-cell and bulk RNA-seq analyses. Initially, LASSO analysis was performed to derive a prognostic signature composed of 4 key genes, including CD14, CTSS, CXCL8 and THBS1. Subsequently, mendelian randomization and survival analysis demonstrated that only CTSS showed crucially protective role in sepsis development and prognosis. Next, CTSS was confirmed to be lower expressed in peripheral monocytes of septic patients. Inflammatory markers (p < 0.05) and migration ability of LPS-activated monocytes were significantly reduced after CTSS agonist. In addition, CTSS agonist decreased the pulmonary tissue monocyte/macrophages infiltration in septic mice.

Conclusion

Monocyte marker CTSS represent a promising target for the diagnosis and prognosis evaluation of sepsis and plays a critical role in monocytes activation, tissue inflammatory response and macrophages infiltration. Thus, CTSS agonist probably serves as new drug for clinical protection against sepsis.

Plac8-ERK pathway modulation of monocyte function in sepsis

Sepsis, a life-threatening condition caused by infection, is characterized by the dysregulation of immune responses and activation of monocytes. Plac8, a protein, has been implicated in various inflammatory conditions. This study aimed to investigate the effect of Plac8 upregulation on monocyte proliferation and activation in sepsis patients. Peripheral blood samples were collected from healthy individuals and sepsis patients. Monocytes were stimulated with lipopolysaccharide (LPS) to create an in vitro sepsis model, while a murine sepsis model was established using cecal ligation and puncture (CLP). The levels of monocyte markers, proliferation index (PI), and pro-inflammatory cytokines were assessed using flow cytometry and qPCR, respectively. Plac8 and phosphorylated ERK protein levels were determined by western blot, and TNF-α, IL-6, and IL-10 levels were quantified using ELISA. The CCK-8 assay was used to evaluate PBMC proliferation and activation. The results showed that Plac8 was highly expressed in sepsis models, promoting the survival, proliferation, and activation of monocytes. Plac8 upregulation activated the ERK pathway, leading to increased phosphorylation of ERK protein and elevated levels of CD14, CD16, TNF-α, IL-6, Plac8, and IL-10. In sepsis mice, Plac8 overexpression similarly activated the ERK pathway and promoted the survival, proliferation, and activation of monocytes. In conclusion, the upregulation of Plac8 enhances the activation of the ERK pathway and promotes monocyte proliferation and activation in sepsis patients.

Endotoxin tolerance and trained immunity: breaking down immunological memory barriers

For decades, innate immune cells were considered unsophisticated first responders, lacking the adaptive memory of their T and B cell counterparts. However, mounting evidence demonstrates the surprising complexity of innate immunity. Beyond quickly deploying specialized cells and initiating inflammation, two fascinating phenomena - endotoxin tolerance (ET) and trained immunity (TI) - have emerged. ET, characterized by reduced inflammatory response upon repeated exposure, protects against excessive inflammation. Conversely, TI leads to an enhanced response after initial priming, allowing the innate system to mount stronger defences against subsequent challenges. Although seemingly distinct, these phenomena may share underlying mechanisms and functional implications, blurring the lines between them. This review will delve into ET and TI, dissecting their similarities, differences, and the remaining questions that warrant further investigation.

Unraveling the role of HIF-1α in sepsis: from pathophysiology to potential therapeutics-a narrative review

Sepsis is characterized by organ dysfunction resulting from a dysregulated inflammatory response triggered by infection, involving multifactorial and intricate molecular mechanisms. Hypoxia-inducible factor-1α (HIF-1α), a notable transcription factor, assumes a pivotal role in the onset and progression of sepsis. This review aims to furnish a comprehensive overview of HIF-1α's mechanism of action in sepsis, scrutinizing its involvement in inflammatory regulation, hypoxia adaptation, immune response, and organ dysfunction. The review encompasses an analysis of the structural features, regulatory activation, and downstream signaling pathways of HIF-1α, alongside its mechanism of action in the pathophysiological processes of sepsis. Furthermore, it will delve into the roles of HIF-1α in modulating the inflammatory response, including its association with inflammatory mediators, immune cell activation, and vasodilation. Additionally, attention will be directed toward the regulatory function of HIF-1α in hypoxic environments and its linkage with intracellular signaling, oxidative stress, and mitochondrial damage. Finally, the potential therapeutic value of HIF-1α as a targeted therapy and its significance in the clinical management of sepsis will be discussed, aiming to serve as a significant reference for an in-depth understanding of sepsis pathogenesis and potential therapeutic targets, as well as to establish a theoretical foundation for clinical applications.