Adeyinka Adejumo

Circulating and Exosome-Packaged Hepatitis C Single-Stranded RNA Induce Monocyte Differentiation via TLR7/8 to Polarized Macrophages and Fibrocytes

Monocytes and macrophages (MΦs) play a central role in the pathogenesis of chronic hepatitis C virus (HCV) infection. The tissue microenvironment triggers monocyte differentiation into MΦs, with polarization ranging within the spectrum of M1 (classical) to M2 (alternative) activation. Recently, we demonstrated that HCV infection leads to monocyte differentiation into polarized MΦs that mediate stellate cell activation via TGF-β. In this study, we aimed to identify the viral factor(s) that mediate monocyte-to-MΦ differentiation. We performed coculture experiments using healthy monocytes with exosome-packaged HCV, cell-free HCV, or HCV ssRNA. Coculture of monocytes with exosome-packaged HCV, cell-free HCV, or HCV ssRNA induced differentiation into MΦs with high M2 surface marker expression and production of pro- and anti-inflammatory cytokines. The HCV ssRNA–induced monocyte activation and differentiation into MΦs could be prevented by TLR7 or TLR8 knockdown. Furthermore, TLR7 or TLR8 stimulation, independent of HCV, caused monocyte differentiation and M2 MΦ polarization. In vivo, in chronic HCV–infected patients, we found increased expression of TLR7/8 in circulating monocytes that was associated with increased intracellular expression of procollagen. Furthermore, knockdown of TLR8 completely attenuated collagen expression in monocytes exposed to HCV, and knockdown of TLR7 partially attenuated this expression, suggesting roles for TLR7/8 in induction of fibrocytes in HCV infection. We identified TLR7/8 as mediators of monocyte differentiation and M2 MΦ polarization during HCV infection. Further, we demonstrated that HCV ssRNA and other TLR7/8 ligands promote MΦ polarization and generation of circulating fibrocytes.

Cannabis use is associated with reduced prevalence of progressive stages of alcoholic liver disease.

Abusive alcohol use has well‐established health risks including causing liver disease (ALD) characterized by alcoholic steatosis (AS), steatohepatitis (AH), fibrosis, cirrhosis (AC) and hepatocellular carcinoma (HCC). Strikingly, a significant number of individuals who abuse alcohol also use Cannabis, which has seen increased legalization globally. While cannabis has demonstrated anti‐inflammatory properties, its combined use with alcohol and the development of liver disease remain unclear.

Abnormal neutrophil traps and impaired efferocytosis contribute to liver injury and sepsis severity after binge alcohol use

BACKGROUND & AIMS Neutrophil extracellular traps (NETs) are an important strategy utilized by neutrophils to immobilize and kill invading microorganisms. Herein, we studied NET formation and the process of neutrophil cell death (NETosis), as well as the clearance of NETs by macrophages (MΦ) (efferocytosis) in acute sepsis following binge drinking. METHODS Healthy volunteers consumed 2 ml of vodka/kg body weight, before blood endotoxin and 16 s rDNA were measured. Peripheral neutrophils were isolated and exposed to alcohol followed by phorbol 12-myristate 13-acetate (PMA) stimulation. Mice were treated with three alcohol binges and intraperitoneal lipopolysaccharide (LPS) to assess the dynamics of NET formation and efferocytosis. In vivo, anti-Ly6G antibody (IA8) was used for neutrophil depletion. RESULTS Inducers of NETs (endotoxin and bacterial DNA) significantly increased in the circulation after binge alcohol drinking in humans. Ex vivo, alcohol alone increased NET formation, but upon PMA stimulation alcohol attenuated NET formation. Binge alcohol in mice resulted in a biphasic response to LPS. Initially, binge alcohol reduced LPS-induced NET formation and resulted in a diffuse distribution of neutrophils in the liver compared to alcohol-naïve mice. Moreover, indicators of NET formation including citrullinated histone H3, neutrophil elastase, and neutrophil myeloperoxidase were decreased at an early time point after LPS challenge in mice receiving binge alcohol, suggesting decreased NET formation. However, in the efferocytosis phase (15 h after LPS) citrullinated histone-H3 was increased in the liver in alcohol binge mice, suggesting decreased clearance of NETs. In vitro alcohol treatment reduced efferocytosis and phagocytosis of NETotic neutrophils and promoted expression of CD206 on MΦ. Finally, depletion of neutrophils prior to binge alcohol ameliorated LPS-induced systemic inflammation and liver injury in mice. CONCLUSIONS Dysfunctional NETosis and efferocytosis following binge drinking exacerbate liver injury associated with sepsis. LAY SUMMARY Disease severity in alcoholic liver disease (ALD) is associated with a significant presence of neutrophils (a type of immune cell) in the liver. It remains unknown how alcohol affects the capacity of neutrophils to control infection, a major hallmark of ALD. We found that binge alcohol drinking impaired important strategies used by neutrophils to contain and resolve infection, resulting in increased liver injury during ALD.

Pharmacological inhibition of CCR2/5 signaling prevents and reverses alcohol‐induced liver damage, steatosis and inflammation in mice

Kupffer cell and macrophage (MØ) activation contributes to steatosis, inflammation, and fibrosis in alcoholic liver disease (ALD). We found increased frequency of MØ, T cells, and expression of C‐C chemokine receptor type 2 (Ccr2) and C‐C chemokine receptor type 5 (Ccr5) in the livers of patients with ALD, and increased circulating chemokines, C‐C chemokine ligand types 2 (CCL2), and C‐C chemokine ligand types 5 (CCL5) in patients with alcoholic hepatitis. We hypothesized that inhibition of CCL2 signaling with the dual CCR2/5 inhibitor, cenicriviroc (CVC), would attenuate ALD. In a mouse model of ALD, liver injury (alanine aminotransferase [ALT]) and steatosis were prevented by CVC whether administered as “prevention” throughout the alcohol feeding or as “treatment” started after the development of ALD. Alcohol‐induced increases in early liver fibrosis markers (sirius red, hydroxyproline, and collagen‐1) were normalized by both modes of CVC administration. We found that prevention and treatment with CVC reversed alcohol‐related increases in liver mRNA and protein expression of tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6, and CCL2. CVC administration regimens prevented the increase in infiltrating MØ (F4/80lo CD11bhi) and reduced proinflammatory Ly6Chi MØ in livers of alcohol‐fed mice. CVC increased liver T‐cell numbers and attenuated Il‐2 expression without an effect on CD69+ or CD25+ T‐cell expression. In vitro, CVC inhibited CCL2‐induced increases in hepatocyte fatty acid synthase (Fasn) and adipose differentiation‐related protein (Adrp), whereas it augmented acyl‐coenzyme A oxidase 1 (Acox‐1), proliferator‐activated receptor gamma co‐activator alpha (Pgc1α) and uncoupling protein 2 expression, suggesting mechanisms for attenuated hepatocyte steatosis. We found that CCL2 and CCL5 sensitized hepatocytes to lipopolysaccharide‐induced liver injury (TNF‐α, ALT, and lactate dehydrogenase release). Alcohol feeding induced apoptosis (poly ADP‐ribose polymerase [PARP] and caspase‐3 [CASP‐3] cleavage) and pyroptosis (gasdermin D [GSDMD] cleavage) in livers, and CVC prevented both of these forms of cell death. Conclusion: Together, our data demonstrate preclinical evidence for CCR2/CCR5 inhibition with CVC as a potent intervention to ameliorate alcohol‐induced steatohepatitis and liver damage.

Predictors, Burden, and the Impact of Arrhythmia on Patients Admitted for Acute Myocarditis

A significant proportion of patients with acute myocarditis experience sudden cardiac death presumably due to cardiac arrhythmia. In this study, we explore the burden, the predictors of arrhythmia in acute myocarditis and the association between arrhythmias and adverse in-hospital outcomes. After evaluating the frequency of various tachyarrhythmias and bradyarrhythmia in myocarditis population, we built a logistic model to determine the independent predictors of arrhythmias in myocarditis and a 1:1 propensity-matched analysis to examine the impact of arrhythmias. Overall, cardiac arrhythmias were identified in 33.71% of the hospitalized myocarditis cases. Ventricular tachycardia and atrial fibrillation were most common arrhythmias. There were increased odds of in-hospital mortality, cardiogenic shock, use of mechanical circulatory support, pacemaker implantation, and nonroutine hospital discharges in the arrhythmia cohorts. Length of stay and cost of hospitalization were also significantly higher. A significant proportion of patients with myocarditis have cardiac arrhythmias. As the occurrence of arrhythmias in myocarditis is associated with worse outcomes, it may be important to risk stratify patient to identify those who will benefit from early intervention.