Phosphatidylethanolamine N-methyltransferase (PEMT) Knockout Mice Exhibit Worse Alcohol-Induced Liver Injury than Wildtype Mice

Phosphatidylethanolamine N-methyltransferase (PEMT) is an enzyme that catalyzes the successive transfer of 3 methyl groups from S-adenosylmethionine (SAM) to phosphatidylethanolamine (PE) to generate phosphatidylcholine (PC). PC is vital for exporting fat out of the liver, ultimately preventing hepatic steatosis. Alcohol also induces steatosis partly through damaging this pathway, so the purpose of this study was to investigate the relationship between alcohol and PEMT in the liver. PEMT -/- (KO) and wild-type (WT) mice were subjected to a chronic + binge alcohol treatment, and both serum and liver samples were analyzed. Triglyceride quantification, SAM and S-adenosylhomocysteine (SAH) levels, and histological analyses were performed on liver samples, while ALT levels were determined from serum samples. Our study showed that ethanol-fed PEMT KO mice exhibited worse liver injury compared to other treatment groups. Our results show increased triglyceride levels, increased ALT levels, decreased SAM:SAH ratio, and increased liver to body weight ratio. From these findings, we conclude that additional liver damage is observed with the combination of alcohol feeding and absence of the PEMT enzyme. The mechanism by which these two factors affect one another is a key area of future study.https://digitalcommons.unmc.edu/surp2021/1016/thumbnail.jp

Phosphatidylethanolamine Methyltransferase Deficiency Exacerbates Acute Alcohol-Induced Liver Injury

Alcohol-associated liver disease (ALD) is a global burden of healthcare and remains a major cause of morbidity and mortality worldwide. ALD includes a spectrum of injuries that progresses from hepatic steatosis, alcoholic hepatitis to alcohol-associated cirrhosis and even hepatocellular carcinoma with continued alcohol misuse. The development of ALD depends on several factors, including genetics. The liver enzyme phosphatidylethanolamine methyltransferase (PEMT) catalyzes three sequential methyl transfers to phosphatidylethanolamine, generating phosphatidylcholine (PC). The PC generated with PEMT-mediated catalysis is preferentially used in very-low-density-lipoprotein (VLDL) assembly and is required for its normal biogenesis and secretion (1-3). Alcohol affects the methylation potential and impairs PEMT activity, which by inhibiting VLDL synthesis contributes to the development of hepatic steatosis. Polymorphisms in the human PEMT gene causing loss of function confer susceptibility to metabolic-associated steatohepatitis. Based on these considerations, we hypothesized that PEMT deletion would exacerbate alcohol-induced liver injury. Animal Handling and Diet: Male and female wildtype (WT) and PEMT knock out (KO) mice (12 weeks of age) were subjected to ethanol binge feeding model. The animals were gavaged with maltose dextrin or ethanol (5g/Kg BW) twice, 12 hours apart. The mice were euthanized eight hours after the second dose, where the blood and liver were collected for the following analyses: AST and ALT levels: Serum AST and ALT were analyzed using a VITROS 5.1 FS Chemistry System. Hepatic histopathology: Neutral-buffered formalin fixed liver sections stained with hematoxylin & eosin (H & E) and picrosirius red were imaged using a Keyence BZ-810 microscope. HPLC Analysis: Liver tissues were homogenized in 0.5N perchloric acid and subjected to HPLC analysis to determine S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) levels (3,4) The SAM:SAH ratio, or methylation index, was calculated, as detailed (3,4). Triglyceride Quantification: Lipids were extracted by Folch method (6) and triglyceride levels were quantified using the Thermo DNA Kit (3,4). Enzymatic Activity: Lysosomal acid lipase and proteasome activities were determined in liver homogenates, as detailed (7) Statistical Analyses: Data are expressed as mean values ± standard error (SE). Values not sharing a common subscript letter are statistically different, p \u3c 0.05. We found deletion of PEMT exacerbates acute alcohol-induced liver injury in both males and females as evidenced by: •Increased AST and ALT levels •Increased fat accumulation by histopathological assessment •Decreased SAM levels causing a reduction in the methylation potential •Increased hepatic triglycerides •Decreased lysosomal acid lipase activity •Decreased proteasome activityhttps://digitalcommons.unmc.edu/surp2022/1036/thumbnail.jp

Elevated S-Adenosylhomocysteine Induces Adipocyte Dysfunction to Promote Alcohol-Associated Liver Steatosis

It has been previously shown that chronic ethanol administration-induced increase in adipose tissue lipolysis and reduction in the secretion of protective adipokines collectively contribute to alcohol-associated liver disease (ALD) pathogenesis. Further studies have revealed that increased adipose S-adenosylhomocysteine (SAH) levels generate methylation defects that promote lipolysis. Here, we hypothesized that increased intracellular SAH alone causes additional related pathological changes in adipose tissue as seen with alcohol administration. To test this, we used 3-deazaadenosine (DZA), which selectively elevates intracellular SAH levels by blocking its hydrolysis. Fully differentiated 3T3-L1 adipocytes were treated in vitro for 48 h with DZA and analysed for lipolysis, adipokine release and differentiation status. DZA treatment enhanced adipocyte lipolysis, as judged by lower levels of intracellular triglycerides, reduced lipid droplet sizes and higher levels of glycerol and free fatty acids released into the culture medium. These findings coincided with activation of both adipose triglyceride lipase and hormone sensitive lipase. DZA treatment also significantly reduced adipocyte differentiation factors, impaired adiponectin and leptin secretion but increased release of pro-inflammatory cytokines, IL-6, TNF and MCP-1. Together, our results demonstrate that elevation of intracellular SAH alone by DZA treatment of 3T3-L1 adipocytes induces lipolysis and dysregulates adipokine secretion. Selective elevation of intracellular SAH by DZA treatment mimics ethanol\u27s effects and induces adipose dysfunction. We conclude that alcohol-induced elevations in adipose SAH levels contribute to the pathogenesis and progression of ALD

Targeting IκappaB kinases for cancer therapy

The inhibitory kappa B kinases (IKKs) and IKK related kinases are crucial regulators of the pro-inflammatory transcription factor, nuclear factor kappa B (NF-κB). The dysregulation in the activities of these kinases has been reported in several cancer types. These kinases are known to regulate survival, proliferation, invasion, angiogenesis, and metastasis of cancer cells. Thus, IKK and IKK related kinases have emerged as an attractive target for the development of cancer therapeutics. Several IKK inhibitors have been developed, few of which have advanced to the clinic. These inhibitors target IKK either directly or indirectly by modulating the activities of other signaling molecules. Some inhibitors suppress IKK activity by disrupting the protein-protein interaction in the IKK complex. The inhibition of IKK has also been shown to enhance the efficacy of conventional chemotherapeutic agents. Because IKK and NF-κB are the key components of innate immunity, suppressing IKK is associated with the risk of immune suppression. Furthermore, IKK inhibitors may hit other signaling molecules and thus may produce off-target effects. Recent studies suggest that multiple cytoplasmic and nuclear proteins distinct from NF-κB and inhibitory κB are also substrates of IKK. In this review, we discuss the utility of IKK inhibitors for cancer therapy. The limitations associated with the intervention of IKK are also discussed

Acute Ethanol-Induced Liver Injury is Prevented by Betaine Administration

Binge drinking is the most common form of excessive alcohol use. Repeated episodes of binge drinking cause multiple organ injuries, including liver damage. We previously demonstrated that chronic ethanol administration causes a decline in the intrahepatic ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH). This decline causes impairments in essential methylation reactions that result in alcohol-induced fatty liver (steatosis) and other features of alcohol-associated liver disease (ALD). Co-treatment with betaine during chronic ethanol feeding, normalizes hepatocellular SAM:SAH ratio and alleviates many features of liver damage including steatosis. Here, we sought to examine whether betaine treatment similarly protects against liver injury in an alcohol binge-drinking model. We hypothesized that ethanol binge with prior or simultaneous betaine administration would prevent or attenuate acute alcohol-induced liver damage. Male C57Bl/6 mice were gavaged twice, 12 h apart, with either 6 g ethanol/kg BW or with an equal volume/kg BW of 0.9% NaCl. Two separate groups of mice (n = 5/group) were gavaged with 4 g betaine/kg BW, either 2 h before or simultaneously with the ethanol or saline gavages. All mice were sacrificed 8 h after the last gavage and serum and liver parameters were quantified. Ethanol binges caused a 50% decrease in hepatic SAM:SAH ratio and a \u3e3-fold rise in liver triglycerides (p ≤ 0.05). These latter changes were accompanied by elevated serum AST and ALT activities and blood alcohol concentrations (BAC) that were ∼three-times higher than the legal limit of intoxication in humans. Mice that were treated with betaine 2 h before or simultaneously with the ethanol binges exhibited similar BAC as in mice given ethanol-alone. Both betaine treatments significantly elevated hepatic SAM levels thereby normalizing the SAM:SAH ratio and attenuating hepatic steatosis and other injury parameters, compared with mice given ethanol alone. Simultaneous betaine co-administration with ethanol was more effective in preventing or attenuating liver injury than betaine given before ethanol gavage. Our findings confirm the potential therapeutic value of betaine administration in preventing liver injury after binge drinking in an animal model

Splenectomy and proximal lieno-renal shunt in a factor five deficient patient with extra-hepatic portal vein obstruction

BACKGROUND: The clinico-surgical implication and successful management of a rare case of factor five (V) deficiency with portal hypertension and hypersplenism due to idiopathic extra-hepatic portal venous obstruction is presented. CASE PRESENTATION: A 16-year old boy had gastro-esophageal variceal bleeding, splenomegaly and hypersplenism. During preoperative workup prolonged prothrombin time and activated partial thromboplastin time were detected, which on further evaluation turned out to be due to factor V deficiency. Proximal lieno-renal shunt and splenectomy were successfully performed with transfusion of fresh frozen plasma during and after the surgical procedure. At surgery there was no excessive bleeding. The perioperative course was uneventful and the patient is doing well on follow up. CONCLUSION: Surgical portal decompressive procedures can be safely undertaken in clotting factor deficient patients with portal hypertension if meticulous surgical hemostasis is achieved at operation and the deficient factor is adequately replaced in the perioperative period

Ultra-High-Performance Concrete (UHPC): A state-of-the-art review of material behavior, structural applications and future

Ultra-high-performance concrete commonly known as UHPC is rising curiosity among structural engineers all over. Though early research on this material dates back to a couple of decades, some initial knowledge about this material, its behavior, and its properties is largely limited to a few research circles in a handful of advanced countries. This paper introduces UHPC as a material, elaborates on its ingredients, and describes its properties. A detailed review of available research literature about UHPC is made. The contributions made by several researchers have been discussed in detail. Following this, the structural behavior and strength of the material are reviewed comprehensively. Comparisons are made between conventional concrete and UHPC with respect to their properties, stress-strain relation, cracking behavior, compressive, tensile, and shear strengths. A detailed evaluation is made of the enhanced properties of the material with respect to its durability and long-term performance. The resistance of this material to moisture permeability, chloride ingress, and chemical attacks is understood. The impact resistance and energy absorption characteristics of the material are compared with conventional concrete. The study documented the structural applications of UHPC as well as the potential applications in the field of civil engineering. Finally, the authors enlisted the impacts of this new material (UHPC) on the future direction of structural engineering and the innovative solutions it can provide to structural engineering problem

Effect of Calcination Time on the Catalytic Activity of Ni/γ-Al2O3 Cordierite Monolith for Dry Reforming of Biogas

Ni/γ-Al2O3 wash coated cordierite monolith catalysts are calcined in air at 800 °C for 4, 10, and 20 h in order to study the effect of calcination time on the activity of the catalysts for dry reforming of model biogas. Catalytic activity studies are performed at 800 °C with three different CH4/CO2 ratios of 1.0, 1.5, and 2.0. The catalyst calcined for the longest time (C-20) displays higher stability and activity in terms of CH4 and CO2 conversion compared to those calcined for 4 h (C-4) and 10 h (C-10). XRD data and TPR analysis detect the maximum amount of NiAl2O4/MgAl2O4 phases and strongest metal-support interaction, respectively, for the C-20 sample. FESEM reveals the particle size of the calcined and reduced C-20 sample to be smaller than that of the C-4 and C-10 samples. Whereas, H2 pulse-chemisorption characterization demonstrates the highest metal surface area, metal dispersion, and smallest Ni particle size for the C-20 catalyst. While, no carbon deposition on any catalyst occurs for the CH4/CO2 ratio of one, lowest amount of carbon nanotubes is formed on the C-20 sample for the CH4/CO2 ratio of 1.5 and 2.0, as observe by DTA-TGA. EDX reveals concentration variation of Mg and Si from the cordierite monolith wall along the thickness of the coating for all the samples. In addition, the maximum amount of these elements is observed for the calcined C-20 catalyst coating. These implies that the diffusion of Mg and Si from the cordierite monolith to the catalyst coating during calcination contribute significantly in controlling the physicochemical properties of the catalysts. As a result, the higher stability and activity of the C-20 could be attributed to the formation of higher amount of the Ni– Mg- alumina spinel complex in the catalyst coating during longer calcination time, which leads to the improved metal-support interaction and higher nickel dispersion over monolith

Hepatitis C Virus Infection Induces Autophagy as a Prosurvival Mechanism to Alleviate Hepatic ER-Stress Response

Hepatitis C virus (HCV) infection frequently leads to chronic liver disease, liver cirrhosis and hepatocellular carcinoma (HCC). The molecular mechanisms by which HCV infection leads to chronic liver disease and HCC are not well understood. The infection cycle of HCV is initiated by the attachment and entry of virus particles into a hepatocyte. Replication of the HCV genome inside hepatocytes leads to accumulation of large amounts of viral proteins and RNA replication intermediates in the endoplasmic reticulum (ER), resulting in production of thousands of new virus particles. HCV-infected hepatocytes mount a substantial stress response. How the infected hepatocyte integrates the viral-induced stress response with chronic infection is unknown. The unfolded protein response (UPR), an ER-associated cellular transcriptional response, is activated in HCV infected hepatocytes. Over the past several years, research performed by a number of laboratories, including ours, has shown that HCV induced UPR robustly activates autophagy to sustain viral replication in the infected hepatocyte. Induction of the cellular autophagy response is required to improve survival of infected cells by inhibition of cellular apoptosis. The autophagy response also inhibits the cellular innate antiviral program that usually inhibits HCV replication. In this review, we discuss the physiological implications of the HCV-induced chronic ER-stress response in the liver disease progression