The pleotropic effects of fluvastatin on complement-mediated T-cell activation in hypercholesterolemia

Canonical and non-canonical roles of complement in atherosclerosis

Cardiovascular diseases are the leading cause of death globally, and atherosclerosis is the major contributor to the development and progression of cardiovascular diseases. Immune responses have a central role in the pathogenesis of atherosclerosis, with the complement system being an acknowledged contributor. Chronic activation of liver-derived and serum-circulating canonical complement sustains endothelial inflammation and innate immune cell activation, and deposition of complement activation fragments on inflamed endothelial cells is a hallmark of atherosclerotic plaques. However, increasing evidence indicates that liver-independent, cell-autonomous and non-canonical complement activities are underappreciated contributors to atherosclerosis. Furthermore, complement activation can also have atheroprotective properties. These specific detrimental or beneficial contributions of the complement system to the pathogenesis of atherosclerosis are dictated by the location of complement activation and engagement of its canonical versus non-canonical functions in a temporal fashion during atherosclerosis progression. In this Review, we summarize the classical and the emerging non-classical roles of the complement system in the pathogenesis of atherosclerosis and discuss potential strategies for therapeutic modulation of complement for the prevention and treatment of atherosclerotic cardiovascular disease.

6-Formylindolo[3,2-b]carbazole, a potent ligand for the aryl hydrocarbon receptor, attenuates concanavalin-induced hepatitis by limiting T-cell activation and infiltration of proinflammatory CD11b+ Kupffer cells

FICZ (6-formylindolo[3,2-b]carbazole) is a potent aryl hydrocarbon receptor agonist that has a poorly understood function in the regulation of inflammation. In this study, we investigated the effect of aryl hydrocarbon receptor activation by FICZ in a murine model of autoimmune hepatitis induced by concanavalin A. High-throughput sequencing techniques such as single-cell RNA sequencing and assay for transposase accessible chromatin sequencing were used to explore the mechanisms through which FICZ induces its effects. FICZ treatment attenuated concanavalin A-induced hepatitis, evidenced by decreased T-cell infiltration, decreased circulating alanine transaminase levels, and suppression of proinflammatory cytokines. Concanavalin A revealed an increase in natural killer T cells, T cells, and mature B cells upon concanavalin A injection while FICZ treatment reversed the presence of these subsets. Surprisingly, concanavalin A depleted a subset of CD55+ B cells, while FICZ partially protected this subset. The immune cells showed significant dysregulation in the gene expression profiles, including diverse expression of migratory markers such as CCL4, CCL5, and CXCL2 and critical regulatory markers such as Junb. Assay for transposase accessible chromatin sequencing showed more accessible chromatin in the CD3e promoter in the concanavalin A-only group as compared to the naive and concanavalin A-exposed, FICZ-treated group. While there was overall more accessible chromatin of the Adgre1 (F4/80) promoter in the FICZ-treated group, we observed less open chromatin in the Itgam (CD11b) promoter in Kupffer cells, supporting the ability of FICZ to reduce the infiltration of proinflammatory cytokine producing CD11b+ Kupffer cells. Taken together, these data demonstrate that aryl hydrocarbon receptor activation by FICZ suppresses liver injury through the limitation of CD3+ T-cell activation and CD11b+ Kupffer cell infiltration.

Exploring the hub mechanisms of ischemic stroke based on protein-protein interaction networks related to ischemic stroke and inflammatory bowel disease

Ischemic stroke is highly concerning because it often leads to severe long-term neurological disability. Among clinical trials, ischemic stroke and inflammatory bowel disease interactions have been increasingly reported in recent years. Therefore, using bioinformatics approaches to explore novel protein interactions between them is of interest. We performed this exploratory analysis by using bioinformatics tools such as string to analyze gene data downloaded from NHGRI-GWAS data related to ischemic stroke and inflammatory bowel disease. We constructed a prospective protein interaction network for ischemic stroke and inflammatory bowel disease, identifying cytokine and interleukin-related signaling pathways, Spliceosome, Ubiquitin-Proteasome System (UPS), Thrombus, and Anticoagulation pathways as the crucial biological mechanisms of the network. Furthermore, we also used data-independent acquisition mass spectrometry (DIA-MS) to detect differential protein expression in eight samples, which also suggested that immune system, signal transduction, and hemostasis-related pathways are key signaling pathways. These findings may provide a basis for understanding the interaction between these two states and exploring possible molecular and therapeutic studies in the future.

Impact of dyslipidemia in the development of cardiovascular complications: Delineating the potential therapeutic role of coenzyme Q10

Dyslipidemia is one of the major risk factors for the development of cardiovascular disease (CVD) in patients with type 2 diabetes (T2D). This metabolic anomality is implicated in the generation of oxidative stress, an inevitable process involved in destructive mechanisms leading to myocardial damage. Fortunately, commonly used drugs like statins can counteract the detrimental effects of dyslipidemia by lowering cholesterol to reduce CVD-risk in patients with T2D. Statins mainly function by blocking the production of cholesterol by targeting the mevalonate pathway. However, by blocking cholesterol synthesis, statins coincidently inhibit the synthesis of other essential isoprenoid intermediates of the mevalonate pathway like farnesyl pyrophosphate and coenzyme Q₁₀ (CoQ₁₀). The latter is by far the most important co-factor and co-enzyme required for efficient mitochondrial oxidative capacity, in addition to its robust antioxidant properties. In fact, supplementation with CoQ₁₀ has been found to be beneficial in ameliorating oxidative stress and improving blood flow in subjects with mild dyslipidemia.. Beyond discussing the destructive effects of oxidative stress in dyslipidemia-induced CVD-related complications, the current review brings a unique perspective in exploring the mevalonate pathway to block cholesterol synthesis while enhancing or maintaining CoQ₁₀ levels in conditions of dyslipidemia. Furthermore, this review disscusses the therapeutic potential of bioactive compounds in targeting the downstream of the mevalonate pathway, more importantly, their ability to block cholesterol while maintaining CoQ₁₀ biosynthesis to protect against the destructive complications of dyslipidemia.

Expression of Caspase-3 in Circulating Innate Lymphoid Cells Subtypes Is Altered by Treatment with Metformin and Fluvastatin in High-Fat Diet Fed C57BL/6 Mice

The current study aimed to determine the expression levels of caspase-3 in circulating innate lymphoid cell subtypes (ILCs) in a high-fat diet (HFD)-induced prediabetes mouse model. Another critical point was to assess the therapeutic effects of metformin and fluvastatin in modulating caspase-3 activation in ILCs within these HFD-fed mice. Prominent results showed that mice exposed to HFD for 14 weeks displayed impaired glucose tolerance that was accompanied by elevated levels of low-density lipoprotein cholesterol (LDL-c) and altered haematological profile as characterised by significantly increased concentrations of red blood cell count, white cell count and lymphocytes when compared to those fed a low-fat diet (LFD). Moreover, the expression of caspase-3 in ILC1 and ILC3 was significantly increased in the HFD groups in comparison to the LFD-fed group. Notably, six-week treatment with metformin and fluvastatin reduced the caspase-3 activation in ILC subtypes. The reduced caspase-3 activation in ILC1 was inversely associated with HDL-c levels following metformin treatment. Interestingly, the reduced caspase-3 activation in ILC3 was associated with lower total cholesterol following fluvastatin treatment in these HFD-fed mice. However, there were no differences in activation of caspase-3 on ILC2 or any association between caspase-3 activation and changes in body weight or fasting blood glucose. Thus, while HFD-feeding clearly modulates ILCs, potentially leading to pro-apoptotic mechanisms, metformin and fluvastatin may play a major role in protecting against such metabolic disturbances.

Activated monocytes as a therapeutic target to attenuate vascular inflammation and lower cardiovascular disease-risk in patients with type 2 diabetes: A systematic review of preclinical and clinical studies

Low grade inflammation is associated with the progression of atherosclerosis. Patients with type 2 diabetes (T2D) have altered cholesterol levels, which are targeted by free radicals to promote lipid peroxidation. Elevated levels of monocyte-associated cytokines such as interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and tumor necrosis factor-alpha (TNF-α), subsequently drive endothelial tissue injury. In fact, the levels of circulating platelet-monocyte aggregates in patients with T2D is a robust marker for atherosclerosis and a cardiovascular disease (CVD)-risk factor. To identify eligible studies, we searched the major online databases using PubMed and Google Scholar. The cumulative evidence synthesized in the current review suggests that, traditional therapies which include thiazolidinediones, statins and some calcium channel blockers can be useful in the primary prevention of atherosclerosis by inhibiting the formation of monocyte-derived microparticles, and pro-inflammatory cytokines such as IL-6, TNF-α, MCP-1, and NF-κB in patients with T2D. Future studies are needed to ascertain whether the combination of dietary interventions and glucose or lipid lowering agents can provide an enhanced cardioprotection in patients with T2D.