Dectin-1 as a Potential Inflammatory Biomarker for Metabolic Inflammation in Adipose Tissue of Individuals with Obesity

Genetic variants of dectin-1 and their antifungal immunity impact in hematologic malignancies: A comprehensive systematic review

BACKGROUND

Fungal infections pose a significant threat to individuals with hematologic malignancies due to compromised immune systems. Dectin-1, a pivotal pattern recognition receptor, plays a central role in antifungal immune responses. Understanding its genetic variants' impact is crucial for advancing personalized therapeutic approaches.

METHODS

Employing systematic review methods, studies were meticulously selected and assessed for relevance. Data extraction encompassed Dectin-1 genetic variants, antifungal immune responses, and disease outcomes.

RESULTS

Findings unveiled a complex relationship between Dectin-1 genetic variants and antifungal immunity in hematologic malignancies. Variable associations emerged, influencing susceptibility to fungal infections and disease prognosis. Moreover, implications for treatment outcomes were explored, suggesting potential avenues for tailored interventions.

CONCLUSIONS

This systematic review underscores the need for further investigation into the precise influence of Dectin-1 genetic variants on antifungal immunity and disease progression in hematologic malignancies. Insights gained could pave the way for personalized therapeutic strategies, optimizing infection prevention and malignancy management. By delving into the intricate connections between genetic nuances, immune responses, and clinical trajectories, this review contributes to the ongoing discourse surrounding hematologic malignancies, fungal infections, and their multifaceted interplay.

Investigation of microglial diversity in a LRRK2 G2019S mouse model of Parkinson's disease

Microglia contribute to the outcomes of various pathological conditions including Parkinson's disease (PD). Microglia are heterogenous, with a variety of states recently identified in aging and neurodegenerative disease models. Here, we delved into the diversity of microglia in a preclinical PD model featuring the G2019S mutation in LRRK2, a known pathological mutation associated with PD. Specifically, we investigated the 'dark microglia' (DM) and the 'disease-associated microglia' (DAM) which present a selective enrichment of CLEC7A expression. In the dorsal striatum - a region affected by PD pathology - extensive ultrastructural features of cellular stress as well as reduced direct cellular contacts, were observed for microglia from old LRRK2 G2019S mice versus controls. In addition, DM were more prevalent while CLEC7A-positive microglia had extensive phagocytic ultrastructural characteristics in the LRRK2 G2019S mice. Furthermore, our findings revealed a higher proportion of DM in LRRK2 G2019S mice, and an increased number of CLEC7A-positive cells with age, exacerbated by the pathological mutation. These CLEC7A-positive cells exhibited a selective enrichment of ameboid morphology and tended to cluster in the affected animals. In summary, we provide novel insights into the occurrence and features of recently defined microglial states, CLEC7A-positive cells and DM, in the context of LRRK2 G2019S PD pathology.

Gut mycobiome in metabolic diseases: Mechanisms and clinical implication

Obesity, type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) are three common metabolic diseases with high prevalence worldwide. Emerging evidence suggests that gut dysbiosis may influence the development of metabolic diseases, in which gut fungal microbiome (mycobiome) is actively involved. In this review, we summarize the studies exploring the composition changes of gut mycobiome in metabolic diseases and mechanisms by which fungi affect the development of metabolic diseases. The current mycobiome-based therapies, including probiotic fungi, fungal products, anti-fungal agents and fecal microbiota transplantation (FMT), and their implication in treating metabolic diseases are discussed. We highlight the unique role of gut mycobiome in metabolic diseases, providing perspectives for future research on gut mycobiome in metabolic diseases.

scPLAN: a hierarchical computational framework for single transcriptomics data annotation, integration and cell-type label refinement

MOTIVATION

In the past decade, single-cell RNA sequencing (scRNA-seq) has emerged as a pivotal method for transcriptomic profiling in biomedical research. Precise cell-type identification is crucial for subsequent analysis of single-cell data. And the integration and refinement of annotated data are essential for building comprehensive databases. However, prevailing annotation techniques often overlook the hierarchical organization of cell types, resulting in inconsistent annotations. Meanwhile, most existing integration approaches fail to integrate datasets with different annotation depths and none of them can enhance the labels of outdated data with lower annotation resolutions using more intricately annotated datasets or novel biological findings.

RESULTS

Here, we introduce scPLAN, a hierarchical computational framework designed for scRNA-seq data analysis. scPLAN excels in annotating unlabeled scRNA-seq data using a reference dataset structured along a hierarchical cell-type tree. It identifies potential novel cell types in a systematic, layer-by-layer manner. Additionally, scPLAN effectively integrates annotated scRNA-seq datasets with varying levels of annotation depth, ensuring consistent refinement of cell-type labels across datasets with lower resolutions. Through extensive annotation and novel cell detection experiments, scPLAN has demonstrated its efficacy. Two case studies have been conducted to showcase how scPLAN integrates datasets with diverse cell-type label resolutions and refine their cell-type labels.

AVAILABILITY

https://github.com/michaelGuo1204/scPLAN.

The Microbiome Modulates the Immune System to Influence Cancer Therapy

The gut microbiota composition can affect the tumor microenvironment and its interaction with the immune system, thereby having implications for treatment predictions. This article reviews the studies available to better understand how the gut microbiome helps the immune system fight cancer. To describe this fact, different mechanisms and approaches utilizing probiotics to improve advancements in cancer treatment will be discussed. Moreover, not only calorie intake but also the variety and quality of diet can influence cancer patients' immunotherapy treatment because dietary patterns can impair immunological activities either by stimulating or suppressing innate and adaptive immunity. Therefore, it is interesting and critical to understand gut microbiome composition as a biomarker to predict cancer immunotherapy outcomes and responses. Here, more emphasis will be given to the recent development in immunotherapies utilizing microbiota to improve cancer therapies, which is beneficial for cancer patients.

HIF-1α promotes virus replication and cytokine storm in H1N1 virus-induced severe pneumonia through cellular metabolic reprogramming

The mortality of patients with severe pneumonia caused by H1N1 infection is closely related to viral replication and cytokine storm. However, the specific mechanisms triggering virus replication and cytokine storm are still not fully elucidated. Here, we identified hypoxia inducible factor-1α (HIF-1α) as one of the major host molecules that facilitates H1N1 virus replication followed by cytokine storm in alveolar epithelial cells. Specifically, HIF-1α protein expression is upregulated after H1N1 infection. Deficiency of HIF-1α attenuates pulmonary injury, viral replication and cytokine storm in vivo. In addition, viral replication and cytokine storm were inhibited after HIF-1α knockdown in vitro. Mechanistically, the invasion of H1N1 virus into alveolar epithelial cells leads to a shift in glucose metabolism to glycolysis, with rapid production of ATP and lactate. Inhibition of glycolysis significantly suppresses viral replication and inflammatory responses. Further analysis revealed that H1N1-induced HIF-1α can promote the expression of hexokinase 2 (HK2), the key enzyme of glycolysis, and then not only provide energy for the rapid replication of H1N1 virus but also produce lactate, which reduces the accumulation of the MAVS/RIG-I complex and inhibits IFN-α/β production. In conclusion, this study demonstrated that the upregulation of HIF-1α by H1N1 infection augments viral replication and cytokine storm by cellular metabolic reprogramming toward glycolysis mainly through upregulation of HK2, providing a theoretical basis for finding potential targets for the treatment of severe pneumonia caused by H1N1 infection.

Regulatory roles of CARD9-BCL10-Rac1 (CBR) signalome in islet β-cell function in health and metabolic stress: Is there room for MALT1?

It is widely accepted that pancreatic islet β-cell failure and the onset of type 2 diabetes (T2DM) constitute an intricate interplay between the genetic expression of the disease and a host of intracellular events including increased metabolic (oxidative, endoplasmic reticulum) stress under the duress of glucolipotoxicity. Emerging evidence implicates unique roles for Caspase Recruitment Domain containing protein 9 (CARD9) in the onset of metabolic diseases, including obesity and insulin resistance. Mechanistically, CARD9 has been implicated in the regulation of p38MAPK and NFkB signaling pathways culminating in cellular dysfunction. Several regulatory factors, including B-cell lymphoma/leukemia 10 (BCL10) have been identified as modulators of CARD9 function in multiple cell types. Despite this evidence on regulatory roles of CARD9-BCL10 signalome in the onset of various pathological states, putative roles of this signaling module in islet β-cell dysfunction in metabolic stress remain less understood. This brief review is aimed at highlighting roles for CARD9 in islet β-cell function under acute (physiological insulin secretion) and long-term (cell dysfunction) exposure to glucose. Emerging roles of other signaling proteins, such as Rac1, BCL10 and MALT1 as contributors to CARD9 signaling in the islet β-cells are also reviewed. Potential avenues for future research toward the development of novel therapeutics for the prevention CARD9-BCL10-Rac1 (CBR) signalome-induced β-cell defects under metabolic stress are discussed.

TNFα induces matrix metalloproteinase-9 expression in monocytic cells through ACSL1/JNK/ERK/NF-kB signaling pathways

Studies have established the association between increased plasma levels of matrix metalloproteinase (MMP)-9 and adipose tissue inflammation. Tumor necrosis factor α (TNFα) was elevated in obesity and is involved in the induction of MMP-9 in monocytic cells. However, the underlying molecular mechanism was incompletely understood. As per our recent report, TNFα mediates inflammatory responses through long-chain acyl-CoA synthetase 1 (ACSL1). Therefore, we further investigated the role of ACSL1 in TNFα-mediated MMP-9 secretion in monocytic cells. THP-1 cells and primary monocytes were used to study MMP-9 expression. mRNA and protein levels of MMP-9 were determined by qRT-PCR and ELISA, respectively. Signaling pathways were studied using Western blotting, inhibitors, and NF-kB/AP1 reporter cells. We found that THP-1 cells and primary human monocytes displayed increased MMP-9 mRNA expression and protein secretion after incubation with TNFα. ACSL1 inhibition using triacsin C significantly reduced the expression of MMP-9 in the THP-1 cells. However, the inhibition of β-oxidation and ceramide biosynthesis did not affect the TNFα-induced MMP-9 production. Using small interfering RNA-mediated ACSL1 knockdown, we further confirmed that TNFα-induced MMP-9 expression/secretion was significantly reduced in ACSL1-deficient cells. TNFα-mediated MMP-9 expression was also significantly reduced by the inhibition of ERK1/ERK2, JNK, and NF-kB. We further observed that TNFα induced phosphorylation of SAPK/JNK (p54/46), ERK1/2 (p44/42 MAPK), and NF-kB p65. ACSL1 inhibition reduced the TNFα-mediated phosphorylation of SAPK/JNK, c-Jun, ERK1/2, and NF-kB. In addition, increased NF-κB/AP-1 activity was inhibited in triacsin C treated cells. Altogether, our findings suggest that ACSL1/JNK/ERK/NF-kB axis plays an important role in the regulation of MMP-9 induced by TNFα in monocytic THP-1 cells.

Metabolic Inflammation and Cellular Immunity

Metabolic and immune cell responses are intimately linked and cross-regulated [...].

Standardized Sanguisorba officinalis L. Extract Inhibits Adipogenesis and Promotes Thermogenesis via Reducing Oxidative Stress

Obesity produces many health problems, including systemic oxidative stress. This study comprehensively investigated the effects of Sanguisorba officinalis L. extract (SO) as an antioxidant on abnormal lipid accumulation and oxidative stress in 3T3-L1 adipocytes and high-fat diet (HFD)-induced obese mice (n = 48). We evaluated the anti-adipogenic and antioxidant effects of SO on 3T3-L1 by cell viability, Oil red O staining, and NBT assays. The ameliorative effects of SO in HFD-induced C57BL/6J mice were investigated by measuring body weight, serum lipids, adipocyte size, hepatic steatosis, AMPK pathway-related proteins, and thermogenic factors. In addition, the effect of SO on oxidative stress in obese mice was evaluated by the activity of antioxidant enzymes and the production of lipid peroxidation products and ROS production in adipose tissue. We found that SO dose-dependently decreased lipid accumulation and ROS production in 3T3-L1 adipocytes. In C57BL/6J obese mice, SO (above 200 mg/kg) attenuated the HFD-induced gain in body weight and white adipose tissue (WAT) weight without affecting appetite. SO also decreased serum glucose, lipid, and leptin levels and attenuated adipocyte hypertrophy and hepatic steatosis. Furthermore, SO increased the expression of SOD1 and SOD2 in WAT, decreased ROS and lipid peroxides, and activated the AMPK pathway and thermogenic factors. In summary, SO reduces oxidative stress in adipose tissue by increasing antioxidant enzyme activity and improves obesity symptoms through AMPK-pathway-regulated energy metabolism and mitochondrial respiratory thermogenesis.

Adipose Tissue Caveolin-1 Upregulation in Obesity Involves TNF-α/NF-κB Mediated Signaling

Obesity is characterized by chronic low-grade inflammation. Obese people have higher levels of caveolin-1 (CAV1), a structural and functional protein present in adipose tissues (ATs). We aimed to define the inflammatory mediators that influence CAV1 gene regulation and the associated mechanisms in obesity. Using subcutaneous AT from 27 (7 lean and 20 obese) normoglycemic individuals, in vitro human adipocyte models, and in vivo mice models, we found elevated CAV1 expression in obese AT and a positive correlation between the gene expression of CAV1, tumor necrosis factor-alpha (TNF-α), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). CAV1 gene expression was associated with proinflammatory cytokines and chemokines and their cognate receptors (r ≥ 0.447, p ≤ 0.030), but not with anti-inflammatory markers. CAV1 expression was correlated with CD163, indicating a prospective role for CAV1 in the adipose inflammatory microenvironment. Unlike wild-type animals, mice lacking TNF-α exhibited reduced levels of CAV1 mRNA/proteins, which were elevated by administering exogenous TNF-α. Mechanistically, TNF-α induces CAV1 gene transcription by mediating NF-κB binding to its two regulatory elements located in the CAV1 proximal regulatory region. The interplay between CAV1 and the TNF-α signaling pathway is intriguing and has potential as a target for therapeutic interventions in obesity and metabolic syndromes.

Expression of Steroid Receptor RNA Activator 1 (SRA1) in the Adipose Tissue Is Associated with TLRs and IRFs in Diabesity

Steroid receptor RNA activator gene (SRA1) emerges as a player in pathophysiological responses of adipose tissue (AT) in metabolic disorders such as obesity and type 2 diabetes (T2D). We previously showed association of the AT SRA1 expression with inflammatory cytokines/chemokines involved in metabolic derangement. However, the relationship between altered adipose expression of SRA1 and the innate immune Toll-like receptors (TLRs) as players in nutrient sensing and metabolic inflammation as well as their downstream signaling partners, including interferon regulatory factors (IRFs), remains elusive. Herein, we investigated the association of AT SRA1 expression with TLRs, IRFs, and other TLR-downstream signaling mediators in a cohort of 108 individuals, classified based on their body mass index (BMI) as persons with normal-weight (N = 12), overweight (N = 32), and obesity (N = 64), including 55 with and 53 without T2D. The gene expression of SRA1, TLRs-2,3,4,7,8,9,10 and their downstream signaling mediators including IRFs-3,4,5, myeloid differentiation factor 88 (MyD88), interleukin-1 receptor-associated kinase 1 (IRAK1), and nuclear factor-κB (NF-κB) were determined using qRT-PCR and SRA1 protein expression was determined by immunohistochemistry. AT SRA1 transcripts' expression was significantly correlated with TLRs-3,4,7, MyD88, NF-κB, and IRF5 expression in individuals with T2D, while it associated with TLR9 and TRAF6 expression in all individuals, with/without T2D. SRA1 expression associated with TLR2, IRAK1, and IRF3 expression only in individuals with obesity, regardless of diabetes status. Furthermore, TLR3/TLR7/IRAK1 and TLR3/TLR9 were identified as independent predictors of AT SRA1 expression in individuals with obesity and T2D, respectively. Overall, our data demonstrate a direct association between the AT SRA1 expression and the TLRs together with their downstream signaling partners and IRFs in individuals with obesity and/or T2D.