Alcohol exposure differentially effects anti-tumor immunity in females by altering dendritic cell function

Lysine β-hydroxybutyrylation promotes lipid accumulation in alcoholic liver disease

Continuous (chronic or sub-chronic) alcohol consumption induces a metabolic byproduct known as ketone bodies, and the accumulation of ketones leads to a life-threatening syndrome called alcoholic ketoacidosis. However, the mechanism underlining the physiological effects of ketone accumulation in alcoholic liver disease (ALD) is still in its infancy. Here, we discovered that mitochondrial acetyl-CoA accumulation was diverted into the ketogenesis pathway in ethanol-fed mice and ethanol-exposed hepatocytes. Unexpectedly, global protein lysine β-hydroxybutyrylation (Kbhb) was induced in response to increased ketogenesis-derived β-hydroxybutyrate (BHB) levels both in hepatocytes and in livers of mice. Focusing on the solute carrier family (SLCs), we found that SLC25A5 presented obvious Kbhb at lysine residues 147 and 166. Kbhb modifications at these two lysine residues stabilized SLC25A5 expression by blocking ubiquitin-proteasome pathway. Subsequent mutation analysis revealed that Kbhb of SLC25A5 at K147 and K166 had site-specific regulatory roles by increasing peroxisome proliferator activated receptor gamma (PPARγ) expression, which further promoting lipogenesis. Additionally, 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (HMGCS2), a rate-limiting enzyme for BHB production, was profoundly induced by ethanol exposure, and knockout of Hmgcs2 with CRISPR/Cas9 attenuated SLC25A5 Kbhb. Together, our study demonstrated a widespread Kbhb landscape under ethanol exposure and clarified a physiological effect of Kbhb modification on liver lipid accumulation.

A Pathogenic Role of Non-Parenchymal Liver Cells in Alcohol-Associated Liver Disease of Infectious and Non-Infectious Origin

Now, much is known regarding the impact of chronic and heavy alcohol consumption on the disruption of physiological liver functions and the induction of structural distortions in the hepatic tissues in alcohol-associated liver disease (ALD). This review deliberates the effects of alcohol on the activity and properties of liver non-parenchymal cells (NPCs), which are either residential or infiltrated into the liver from the general circulation. NPCs play a pivotal role in the regulation of organ inflammation and fibrosis, both in the context of hepatotropic infections and in non-infectious settings. Here, we overview how NPC functions in ALD are regulated by second hits, such as gender and the exposure to bacterial or viral infections. As an example of the virus-mediated trigger of liver injury, we focused on HIV infections potentiated by alcohol exposure, since this combination was only limitedly studied in relation to the role of hepatic stellate cells (HSCs) in the development of liver fibrosis. The review specifically focusses on liver macrophages, HSC, and T-lymphocytes and their regulation of ALD pathogenesis and outcomes. It also illustrates the activation of NPCs by the engulfment of apoptotic bodies, a frequent event observed when hepatocytes are exposed to ethanol metabolites and infections. As an example of such a double-hit-induced apoptotic hepatocyte death, we deliberate on the hepatotoxic accumulation of HIV proteins, which in combination with ethanol metabolites, causes intensive hepatic cell death and pro-fibrotic activation of HSCs engulfing these HIV- and malondialdehyde-expressing apoptotic hepatocytes.

COVID-19 Vaccination and Alcohol Consumption: Justification of Risks

Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, pharmaceutical companies and research institutions have been actively working to develop vaccines, and the mass roll-out of vaccinations against COVID-19 began in January 2021. At the same time, during lockdowns, the consumption of alcoholic beverages increased. During the peak of vaccination, consumption remained at high levels around the world, despite the gradual relaxation of quarantine restrictions. Two of the popular queries on search engines were whether it is safe to drink alcohol after vaccination and whether this will affect the effectiveness of vaccines. Over the past two years, many studies have been published suggesting that excessive drinking not only worsens the course of an acute respiratory distress syndrome caused by the SARS-CoV-2 virus but can also exacerbate post-COVID-19 syndrome. Despite all sorts of online speculation, there is no specific scientific data on alcohol-induced complications after vaccination in the literature. Most of the published vaccine clinical trials do not include groups of patients with a history of alcohol-use disorders. This review analyzed the well-known and new mechanisms of action of COVID-19 vaccines on the immune system and the effects of alcohol and its metabolites on these mechanisms.

miR-29c-3p promotes alcohol dehydrogenase gene cluster expression by activating an ADH6 enhancer

Alcohol dehydrogenases (ADHs) play vital roles in alcohol metabolism and alcohol toxicity, yet little is known about microRNA-mediated regulation of the ADH gene cluster. Here, we showed that miR-29c activated ADH gene cluster transcription by targeting an enhancer element within the ADH6 gene. miR-29c is differentially expressed in alcoholic liver disease. Following biochemical and molecular evidence demonstrated that miR-29c increased ADH6 mRNA and protein levels without affecting the stability of the ADH6 transcript. Further evidence showed that exogenous miR-29c translocated into the nucleus and then unconventionally bound an enhancer element within the ADH6 gene. Luciferase reporter assay and chromatin immunoprecipitation data indicated that miR-29c activated the enhancer and increased the enrichment of RNA polymerase II at the promoter regions of ADH1A, ADH1B, ADH1C, ADH4, and ADH6. Finally, exogenous miR-29c transfection promoted the expression of ADH1A, ADH1B, ADH1C, and ADH4 pre-mRNA and mRNA transcripts from the ADH gene cluster. In conclusion, our data suggest that miR-29c might be a novel epigenetic regulator involved in ADH gene cluster activation.

Role of alcohol in pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) and alcohol abuse often contribute to the development of end-stage liver disease. Alcohol abuse not only causes rapid progression of liver disease in HBV infected patients but also allows HBV to persist chronically. Importantly, the mechanism by which alcohol promotes the progression of HBV-associated liver disease are not completely understood. Potential mechanisms include a suppressed immune response, oxidative stress, endoplasmic reticulum and Golgi apparatus stresses, and increased HBV replication. Certainly, more research is necessary to gain a better understanding of these mechanisms such that treatment(s) to prevent rapid liver disease progression in alcohol-abusing HBV patients could be developed. In this review, we discuss the aforementioned factors for the higher risk of liver diseases in alcohol-induced HBV pathogenies and suggest the areas for future studies in this field.

Psoriasis and alcohol

Psoriasis is a chronic inflammatory skin disease that may be triggered or worsened by several factors, including alcohol. A higher than average alcohol consumption is common among individuals with psoriasis. Neurobiological signaling affected by alcohol intake includes a range of neurotransmitters, such as the dopaminergic, serotonergic, and tachykinergic systems, involved in reward and drug-seeking. These neurotransmitters may also have an impact on the inflammatory processes per se in psoriasis. Future therapy may, therefore, be targeted at neurotransmitter networks involved with both alcohol intake and the inflammatory processes.

Trichostatin A Shows Transient Protection from Chronic Alcohol-Induced Reactive Oxygen Species (ROS) Production in Human Monocyte-Derived Dendritic Cells

OBJECTIVE

The objective of this study was to understand whether histone deacetylase (HDACs) inhibitor Trichostatin A or TSA can block and/or reverse chronic alcohol exposure-induced ROS in human monocyte-derived dendritic cells (MDDCs). Additionally, since nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a known regulator of antioxidant responses, we studied the effects of alcohol and TSA on ROS production and modulation of Nrf2 by MDDCs.

METHODS

Intra-cellular, extra-cellular, and total ROS levels were measured in MDDCs treated chronically with alcohol (0.1 and 0.2 % EtOH) using 2',7'-dichlorofluorescin diacetate (DCF-DA) followed by detection of ROS in microplate reader and imaging flow cytometer. Nrf2 expression was analyzed by qRT- PCR and western blot. In addition, NFE2L2 (Nrf2), class I HDAC genes HDAC1, HDAC2, and histone acetyltransferase genes KAT5 were analyzed in silico using the GeneMania prediction server.

RESULTS

Our results confirmed alcohol's ability to increase intracellular ROS levels in MDDCs within minutes of treatment. Our findings have also demonstrated, for the first time, that TSA has a transient protective effect on MDDCs treated chronically with alcohol since the ability of TSA to reduce intracellular ROS levels is only detected up to 15 minutes post-chronic alcohol treatment with no significant protective effects by 10 hours. In addition, chronic alcohol treatment was able to increase the expression of the antioxidant regulator Nrf2 in a dose dependent manner, and the effect of the higher amount of alcohol (0.2%) on Nrf2 gene expression was significantly enhanced by TSA.

CONCLUSION

This study demonstrates that TSA has a transient protective effect against ROS induced by chronic alcohol exposure of human MDDCs and chronic long-term exposure of MDDCs with alcohol and TSA induces cellular toxicity. It also highlights imaging flow cytometry as a novel tool to detect intracellular ROS levels. Overall, the effect of TSA might be mediated through Nrf2; however, further studies are needed to fully understand the molecular mechanisms.

Targeting myeloid-derived suppressor cells using all-trans retinoic acid in melanoma patients treated with Ipilimumab

BACKGROUND

Immune checkpoint inhibitors have improved overall survival rates for many cancers, yet the majority of patients do not respond to treatment and succumb to disease progression. One tumor-related mechanism limiting the efficacy of immunotherapies in melanoma is the recruitment and expansion of myeloid-derived suppressor cells (MDSCs). Therefore, targeting MDSCs in combination with immunotherapies is an attractive strategy to improve response rates and effectiveness.

METHODS

We tested this strategy by designing a randomized phase II clinical trial treating advanced melanoma patients with either Ipilimumab monotherapy or Ipilimumab plus all-trans retinoic acid (ATRA). Clinicaltrails.gov identifier (NCT02403778). The frequency of circulating MDSCs and the activation of CD8(+) T cells was measured by flow cytometry. Expression of immunosuppressive genes was measured with quantitative real time-PCR. T cell suppressive functions were measured by mixed lymphocyte reaction.

RESULTS

Here we show that in vitro treatment with ATRA decreases immunosuppressive function of MDSCs in mixed lymphocyte reactions. Additionally, ATRA reduces the expression of immunosuppressive genes including PD-L1, IL-10, and indoleamine 2,3‑dioxygenase by MDSCs. Furthermore, the addition of ATRA to standard of care Ipilimumab therapy appears safe, as ATRA did not increase the frequency of grade 3 or 4 adverse events. Finally, ATRA significantly decreased the frequency of circulating MDSCs compared to Ipilimumab treatment alone in advanced-stage melanoma patients.

CONCLUSIONS

These results illustrate the importance of MDSCs in immunotherapy resistance and provide evidence that targeting MDSCs in cancer patients may augment immunotherapeutic approaches.