Ethanol inhibits pancreatic acinar cell autophagy through upregulation of ATG4B, mediating pathological responses of alcoholic pancreatitis.

Excessive alcohol intake is a major risk factor for pancreatitis, sensitizing the exocrine pancreas to stressors by mechanisms that remain obscure. Impaired autophagy drives nonalcoholic pancreatitis, but the effects of ethanol (EtOH) and alcoholic pancreatitis on autophagy are poorly understood. Here, we find that ethanol reduces autophagosome formation in pancreatic acinar cells, both in a mouse model of alcoholic pancreatitis induced by a combination of EtOH diet and cerulein (a CCK ortholog) and in EtOH+CCK-treated acinar cells (ex vivo model). Ethanol treatments decreased pancreatic level of LC3-II, a key mediator of autophagosome formation. This was caused by ethanol-induced upregulation of ATG4B, a cysteine protease that, cell dependently, regulates the balance between cytosolic LC3-I and membrane-bound LC3-II. We show that ATG4B negatively regulates LC3-II in acinar cells subjected to EtOH treatments. Ethanol raised ATG4B level by inhibiting its degradation, enhanced ATG4B enzymatic activity, and strengthened its interaction with LC3-II. We also found an increase in ATG4B and impaired autophagy in a dissimilar, nonsecretagogue model of alcoholic pancreatitis induced by EtOH plus palmitoleic acid. Adenoviral ATG4B overexpression in acinar cells greatly reduced LC3-II and inhibited autophagy. Furthermore, it aggravated trypsinogen activation and necrosis, mimicking key responses of ex vivo alcoholic pancreatitis. Conversely, shRNA Atg4B knockdown enhanced autophagosome formation and alleviated ethanol-induced acinar cell damage. The results reveal a novel mechanism, whereby ethanol inhibits autophagosome formation and thus sensitizes pancreatitis, and a key role of ATG4B in ethanol's effects on autophagy. Enhancing pancreatic autophagy, particularly by downregulating ATG4B, could be beneficial in mitigating the severity of alcoholic pancreatitis.NEW & NOTEWORTHY Ethanol sensitizes mice and humans to pancreatitis, but the underlying mechanisms remain obscure. Autophagy is important for maintaining pancreatic acinar cell homeostasis, and its impairment drives pancreatitis. This study reveals a novel mechanism, whereby ethanol inhibits autophagosome formation through upregulating ATG4B, a key cysteine protease. ATG4B upregulation inhibits autophagy in acinar cells and aggravates pathological responses of experimental alcoholic pancreatitis. Enhancing pancreatic autophagy, particularly by down-regulating ATG4B, could be beneficial for treatment of alcoholic pancreatitis.

Prospective clinical trials and novel therapies in the medical management of severe alcohol-associated hepatitis.

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Naltrexone for alcohol use disorder: Hepatic safety in patients with and without liver disease.

Naltrexone is an approved drug for management of alcohol use disorder (AUD), but data in patients with liver disease (LD) are limited. We aimed to evaluate the safety of naltrexone in those with LD. This is a retrospective cohort of adults with and without LD who were prescribed naltrexone for AUD from 2015 to 2019 in a safety-net setting. Naltrexone hepatic safety was determined by liver enzyme changes during and after compared to before naltrexone prescription as well as rates of subsequent hospitalization and death by Kaplan-Meier methods. Factors associated with hospitalization were examined by Cox regression. Of 160 patients prescribed naltrexone for AUD, 100 (63%) had LD and 47 (47%) of those with LD had cirrhosis (47% decompensated). The total cohort, LD, and cirrhosis groups had lower adjusted mean aspartate aminotransferase and alanine aminotransferase levels after versus before naltrexone prescription (p < 0.001). Two-year survival was 97.7% (95% confidence interval [CI], 84.6-99.7), 95.4% (95% CI, 82.8-98.8), 90.8% (95% CI, 73.5-97.0), and 81.3% (95% CI, 41.2-93.8) in those without LD, LD without cirrhosis, cirrhosis, and decompensated cirrhosis groups (p = 0.46), respectively. Alcohol-related 2-year hospitalization rates were 8.2% (95% CI, 2.7-24), 27.7% (95% CI, 16.6-44.0), 40.5% (95% CI, 24.8-61.6), and 41.7% (95% CI, 23.3-66.6) for the groups without LD, LD without cirrhosis, cirrhosis, and decompensated cirrhosis (p = 0.007), respectively. Independent predictors of subsequent hospitalization were LD, (hazard ratio [HR], 3.70; 95% CI, 1.19-11.51; p = 0.02), cirrhosis (HR, 5.16; 95% CI, 1.69-15.75), and shorter duration (≤30 days) of naltrexone prescription (HR, 2.50; 95% CI, 1.l2-5.20; p = 0.01). Conclusion: Naltrexone is safe to use in patients with underlying LD, including those with compensated cirrhosis. Although encouraging, more safety data are needed for those with decompensated cirrhosis.

Safety of Immunizations for the Adult Patient With Inflammatory Bowel Disease-A Systematic Review and Meta-analysis.

BACKGROUND: Patients with inflammatory bowel disease (IBD) have low vaccination rates for vaccine-preventable diseases. Fear of adverse reactions (AEs) appear to negatively affect vaccination efforts. We aimed to systemically review the risks for AEs following immunization for patients with IBD. METHODS: We searched PubMed and Embase until April 15, 2020, for studies evaluating the safety of vaccinations among patients with IBD. The primary outcome was the incidence of systemic and local AEs among vaccinated patients. Secondary outcome was the rate of IBD flare following immunization. We utilized a random effects meta-analysis of proportions using the DerSimonian-Laird approach to estimate the safety of immunizations. RESULTS: A total of 13 studies with 2116 patients was included in our analysis after fulfilling our inclusion criteria. Seven studies examined the influenza vaccine, 4 the pneumococcal vaccine, 1 the recombinant zoster vaccine, and 1 the hepatitis B vaccine. Follow-up of patients was up to 6 months. The majority of AEs were local, with a pooled incidence of 24% (95% CI, 9%-42%) for all vaccines. Systemic AEs were mostly mild, without resulting in hospitalizations or deaths, with a pooled incidence of 16% (95% CI, 6%-29%) for all vaccines. Flare of inflammatory bowel disease after vaccination found with a pooled incidence of 2% (95% CI, 1%-4%) and we include in the analysis data from all immunizations examined. DISCUSSION: Our study demonstrated that AEs after vaccination are mainly local or mildly systemic and do not differ significantly from the expected AE after recommended immunizations for the general population. Thus, gastroenterologists should reinforce that vaccines are safe in patients with IBD.

Transgenic expression of GFP-LC3 perturbs autophagy in exocrine pancreas and acute pancreatitis responses in mice.

Pancreatitis is a common, sometimes fatal, disease of exocrine pancreas, initiated by damaged acinar cells. Recent studies implicate disordered macroautophagy/autophagy in pancreatitis pathogenesis. ATG8/LC3 protein is critical for autophagosome formation and a widely used marker of autophagic vacuoles. Transgenic GFP-LC3 mice are a valuable tool to investigate autophagy ; however, comparison of homeostatic and disease responses between GFP-LC3 and wild-type (WT) mice has not been done. We examined the effects of GFP-LC3 expression on autophagy, acinar cell function, and experimental pancreatitis. Unexpectedly, GFP-LC3 expression markedly increased endogenous LC3-II level in pancreas, caused by downregulation of ATG4B, the protease that deconjugates/delipidates LC3-II. By contrast, GFP-LC3 expression had lesser or no effect on autophagy in liver, lung and spleen. Autophagic flux analysis showed that autophagosome formation in GFP-LC3 acinar cells increased 3-fold but was not fully counterbalanced by increased autophagic degradation. Acinar cell (ex vivo) pancreatitis inhibited autophagic flux in WT and essentially blocked it in GFP-LC3 cells. In vivo pancreatitis caused autophagy impairment in WT mice, manifest by upregulation of LC3-II and SQSTM1/p62, increased number and size of autophagic vacuoles, and decreased level of TFEB, all of which were exacerbated in GFP-LC3 mice. GFP-LC3 expression affected key pancreatitis responses; most dramatically, it worsened increases in serum AMY (amylase), a diagnostic marker of acute pancreatitis, in several mouse models. The results emphasize physiological importance of autophagy for acinar cell function, demonstrate organ-specific effects of GFP-LC3 expression, and indicate that application of GFP-LC3 mice in disease models should be done with caution.Abbreviations: AP: acute pancreatitis; Arg-AP: L-arginine-induced acute pancreatitis; ATG: autophagy-related (protein); AVs: autophagic vacuoles; CCK: cholecystokinin-8; CDE: choline-deficient, D,L-ethionine supplemented diet; CER: caerulein (ortholog of CCK); CTSB: cathepsin B; CTSD: cathepsin D; CTSL: cathepsin L; ER: endoplasmic reticulum; LAMP: lysosomal-associated membrane protein; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; TEM: transmission electron microscopy; TFEB: transcription factor EB; ZG: zymogen granule(s).

NOD-like receptor C4 Inflammasome Regulates the Growth of Colon Cancer Liver Metastasis in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) enhances the growth and recurrence of colorectal cancer (CRC) liver metastasis. With the rising prevalence of NAFLD, a better understanding of the molecular mechanism underlying NAFLD-associated liver metastasis is crucial. Tumor-associated macrophages (TAMs) constitute a large portion of the tumor microenvironment that promotes tumor growth. NOD-like receptor C4 (NLRC4), a component of an inflammasome complex, plays a role in macrophage activation and interleukin (IL)-1ß processing. We aimed to investigate whether NLRC4-mediated TAM polarization contributes to metastatic liver tumor growth in NAFLD. Wild-type and NLRC4-/- mice were fed low-fat or high-fat diet for 6 weeks followed by splenic injection of mouse CRC MC38 cells. The tumors were analyzed 2 weeks after CRC cell injection. High-fat diet-induced NAFLD significantly increased the number and size of CRC liver metastasis. TAMs and CD206-expressing M2 macrophages accumulated markedly in tumors in the presence of NAFLD. NAFLD up-regulated the expression of IL-1ß, NLRC4, and M2 markers in tumors. In NAFLD, but not normal livers, deletion of NLRC4 decreased liver tumor growth accompanied by decreased M2 TAMs and IL-1ß expression in tumors. Wild-type mice showed increased vascularity and vascular endothelial growth factor (VEGF) expression in tumors with NAFLD, but these were reduced in NLRC4-/- mice. When IL-1 signaling was blocked by recombinant IL-1 receptor antagonist, liver tumor formation and M2-type macrophages were reduced, suggesting that IL-1 signaling contributes to M2 polarization and tumor growth in NAFLD. Finally, we found that TAMs, but not liver macrophages, produced more IL-1ß and VEGF following palmitate challenge. Conclusion: In NAFLD, NLRC4 contributes to M2 polarization, IL-1ß, and VEGF production in TAMs, which promote metastatic liver tumor growth.

Intestinal Lipolysis Mitigates Nonalcoholic Fatty Liver Disease: New Roles for Carboxylesterase 2c in the Intestine.

The most important argument of this study is that modulation of intestinal lipid metabolism by enhancing intestinal Ces2c expression has the potential to affect hepatic and systemic lipid metabolism, regulating the development of NAFLD and systemic insulin resistance.

Alcoholic liver disease: A current molecular and clinical perspective.

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

The Potential for Circulating Tumor Cells in Pancreatic Cancer Management.

Pancreatic cancer is one the most lethal malignancies. Only a small proportion of patients with this disease benefit from surgery. Chemotherapy provides only a transient benefit. Though much effort has gone into finding new ways for early diagnosis and treatment, average patient survival has only been improved in the order of months. Circulating tumor cells (CTCs) are shed from primary tumors, including pre-malignant phases. These cells possess information about the genomic characteristics of their tumor source in situ, and their detection and characterization holds potential in early cancer diagnosis, prognosis, and treatment. Liquid Biopsies present an alternative to tumor biopsy that are hard to sample. Below we summarize current methods of CTC detection, the current literature on CTCs in pancreatic cancer, and future perspectives.

TAK1-mediated autophagy and fatty acid oxidation prevent hepatosteatosis and tumorigenesis.

The MAP kinase kinase kinase TGFß-activated kinase 1 (TAK1) is activated by TLRs, IL-1, TNF, and TGFß and in turn activates IKK-NF-κB and JNK, which regulate cell survival, growth, tumorigenesis, and metabolism. TAK1 signaling also upregulates AMPK activity and autophagy. Here, we investigated TAK1-dependent regulation of autophagy, lipid metabolism, and tumorigenesis in the liver. Fasted mice with hepatocyte-specific deletion of Tak1 exhibited severe hepatosteatosis with increased mTORC1 activity and suppression of autophagy compared with their WT counterparts. TAK1-deficient hepatocytes exhibited suppressed AMPK activity and autophagy in response to starvation or metformin treatment; however, ectopic activation of AMPK restored autophagy in these cells. Peroxisome proliferator-activated receptor α (PPARα) target genes and ß-oxidation, which regulate hepatic lipid degradation, were also suppressed in hepatocytes lacking TAK1. Due to suppression of autophagy and ß-oxidation, a high-fat diet challenge aggravated steatohepatitis in mice with hepatocyte-specific deletion of Tak1. Notably, inhibition of mTORC1 restored autophagy and PPARα target gene expression in TAK1-deficient livers, indicating that TAK1 acts upstream of mTORC1. mTORC1 inhibition also suppressed spontaneous liver fibrosis and hepatocarcinogenesis in animals with hepatocyte-specific deletion of Tak1. These data indicate that TAK1 regulates hepatic lipid metabolism and tumorigenesis via the AMPK/mTORC1 axis, affecting both autophagy and PPARα activity.