Human alcohol dehydrogenase 1 is an acceptor protein for polyADP-ribosylation

ADP-ribosylation, a multifaceted modification: Functions and mechanisms in aging and aging-related diseases

Aging, a complex biological process, plays key roles the development of multiple disorders referred as aging-related diseases involving cardiovascular diseases, stroke, neurodegenerative diseases, cancers, lipid metabolism-related diseases. ADP-ribosylation is a reversible modification onto proteins and nucleic acids to alter their structures and/or functions. Growing evidence support the importance of ADP-ribosylation and ADP-ribosylation-associated enzymes in aging and age-related diseases. In this review, we summarized ADP-ribosylation-associated proteins including ADP-ribosyl transferases, the ADP-ribosyl hydrolyses and ADP-ribose binding domains. Furthermore, we outlined the latest knowledge about regulation of ADP-ribosylation in the pathogenesis and progression of main aging-related diseases, organism aging and cellular senescence, and we also speculated the underlying mechanisms to better disclose this novel molecular network. Moreover, we discussed current issues and provided an outlook for future research, aiming to revealing the unknown bio-properties of ADP-ribosylation, and establishing a novel therapeutic perspective in aging-related diseases and health aging via targeting ADP-ribosylation.

ADP-ribosylation: An emerging direction for disease treatment

ADP-ribosylation (ADPr) is a dynamically reversible post-translational modification (PTM) driven primarily by ADP-ribosyltransferases (ADPRTs or ARTs), which have ADP-ribosyl transfer activity. ADPr modification is involved in signaling pathways, DNA damage repair, metabolism, immunity, and inflammation. In recent years, several studies have revealed that new targets or treatments for tumors, cardiovascular diseases, neuromuscular diseases and infectious diseases can be explored by regulating ADPr. Here, we review the recent research progress on ART-mediated ADP-ribosylation and the latest findings in the diagnosis and treatment of related diseases.

Brain ethanol metabolism and mitochondria

Alcohol abuse and dependence in humans causes an extreme shift in metabolism for which the human brain is not evolutionarily prepared. Oxidation of ethanol and acetaldehyde are not regulated, making ethanol a dominating metabolic substrate that prevents the activity of enzymes from oxidizing their usual endogenous substrates. The enzymes required to oxidize ethanol across the variety of affected tissues all produce acetaldehyde which is then converted to acetate by aldehyde dehydrogenases (ALDHs). ALDHs are NAD+-dependent enzymes, and mitochondrial ALDH2 is likely the primary contributor to ethanol-derived acetaldehyde clearance in cells. Metabolism of alcohol has several adverse effects on mitochondria including increased free radical levels, hyperacetylation of mitochondrial proteins, and excessive mitochondrial fragmentation. This review discusses the role of astrocytic and neuronal mitochondria in ethanol metabolism that contributes to the acute and chronic changes in mitochondrial function and morphology, that might promote tolerance, dependence and withdrawal. We also propose potential modes of therapeutic intervention to reduce the toxicity of chronic alcohol consumption.

PARPs in lipid metabolism and related diseases

PARPs and tankyrases (TNKS) represent a family of 17 proteins. PARPs and tankyrases were originally identified as DNA repair factors, nevertheless, recent advances have shed light on their role in lipid metabolism. To date, PARP1, PARP2, PARP3, tankyrases, PARP9, PARP10, PARP14 were reported to have multi-pronged connections to lipid metabolism. The activity of PARP enzymes is fine-tuned by a set of cholesterol-based compounds as oxidized cholesterol derivatives, steroid hormones or bile acids. In turn, PARPs modulate several key processes of lipid homeostasis (lipotoxicity, fatty acid and steroid biosynthesis, lipoprotein homeostasis, fatty acid oxidation, etc.). PARPs are also cofactors of lipid-responsive nuclear receptors and transcription factors through which PARPs regulate lipid metabolism and lipid homeostasis. PARP activation often represents a disruptive signal to (lipid) metabolism, and PARP-dependent changes to lipid metabolism have pathophysiological role in the development of hyperlipidemia, obesity, alcoholic and non-alcoholic fatty liver disease, type II diabetes and its complications, atherosclerosis, cardiovascular aging and skin pathologies, just to name a few. In this synopsis we will review the evidence supporting the beneficial effects of pharmacological PARP inhibitors in these diseases/pathologies and propose repurposing PARP inhibitors already available for the treatment of various malignancies.

Integrative transcriptomic-proteomic analysis revealed the flavor formation mechanism and antioxidant activity in rice-acid inoculated with Lactobacillus paracasei and Kluyveromyces marxianus

In the study on fermented acid rice soup (rice-acid) inoculated with L. paracasei H4-11 and K. marxianus L1-1, the concentrations of main flavor components on the third day of fermentation were significantly higher than those on the first day. Transcriptome analysis and proteome analysis based on RNA sequencing and 4D label-free proteomic techniques were combined to provide new insights into the molecular mechanisms of flavor characteristics and antioxidant activity of the two strains during the development of rice-acid. The key up-regulated genes and proteins in L. paracasei and K. marxianus L1-1, which were involved in flavor formation and antioxidant activity in rice-acid development, were different. The KEGG pathways involving the up-regulated genes and proteins in L. paracasei included starch and sucrose metabolism, pyruvate metabolism, amino sugar, and nucleotide sugar metabolism, and glycolysis/guconeogenesis. The KEGG pathways involving the up-regulated genes and proteins in K. marxianus L1-1 mainly included glycolysis/gluconeogenesis, TCA cycle, pyruvate metabolism, and other pathways related to antioxidant capacity. We successfully identified key genes and proteins associated with the metabolism and accumulation of flavor components and antioxidant activity. These findings provide new insights into the molecular mechanisms of flavor formation in co-cultivation with L. paracasei and K. marxianus. SIGNIFICANCE: It is anticipated that this study would provide us an insight into the mechanisms of flavor components accumulation and antioxidant activity of acid rice soup in China's minority areas. Importantly, this research provides the foundation of biological and chemical analysis for the application of the co-culture of L. paracasei H4-11 and K. marxianus in non-dairy products.

NAD metabolism in aging and cancer

IMPACT STATEMENT

NAD is a central metabolite connecting energy balance and organismal growth with genomic integrity and function. It is involved in the development of malignancy and has a regulatory role in the aging process. These processes are mediated by a diverse series of enzymes whose common focus is either NAD's biosynthesis or its utilization as a redox cofactor or enzyme substrate. These enzymes include dehydrogenases, cyclic ADP-ribose hydrolases, mono(ADP-ribosyl)transferases, poly(ADP-ribose) polymerases, and sirtuin deacetylases. This article describes the manifold pathways that comprise NAD metabolism and promotes an increased awareness of how perturbations in these systems may be important in disease prevention and/or progression.