Nicotinamide mononucleotide (NMN) alleviates the poly(I:C)-induced inflammatory response in human primary cell cultures

Spermidine as a Potential Protective Agents Against Poly(I:C)-Induced Immune Response, Oxidative Stress, Apoptosis, and Testosterone Decrease in Yak Leydig Cells

Viral infections of the reproductive tract and testis in male yaks, often resulting from natural mating under grazing conditions, can lead to infertility due to Leydig cell (LC) apoptosis, immune activation, oxidative stress, and reduced testosterone production. Spermidine (SPD), a potential therapeutic agent with antioxidant and anti-aging properties, might alleviate oxidant stress, immune response, and virus infection caused by apoptosis. In this study, firstly testicular Leydig cells of yak were induced with Poly(I:C), the pathogen-associated molecular pattern of the dsRNA virus, as a pathogenic model at the cellular level. Secondly, immune response, apoptosis, oxidative stress, and testosterone synthesis were measured in LC with or without SPD culture medium. Finally, transcriptomic sequencing was utilized to investigate the molecular mechanisms underlying the protective effects of SPD. These results suggested Poly(I:C) damaged the function of Leydig cells, significantly decreased the concentration of testosterone, and induced immune response, oxidative stress, and cell apoptosis, while SPD significantly alleviated the immune response and oxidative stress, and then significantly inhibited cell apoptosis and restores testosterone production in LCs. Transcriptomic analysis revealed that SPD significantly alleviates inflammation and apoptosis induced by Poly(I:C), reducing immune response and cellular damage through the regulation of several key gene expressions. These findings suggest SPD has the potential ability to mitigate Poly(I:C)-induced immune response, oxidative stress, and apoptosis, and then restore testosterone production in Leydig cells, offering a promising strategy to protect and enhance male yak fertility after infection with dsRNA virus.

Nicotinamide mononucleotide combined with PJ-34 protects microglial cells from lipopolysaccharide-induced mitochondrial impairment through NMNAT3-PARP1 axis

Lipopolysaccharide (LPS) is known to induce cell injury and mitochondrial dysfunction, which are pivotal in neuroinflammation and related disorders. Recent studies have demonstrated the potential of nicotinamide mononucleotide (NMN) and poly(ADP-ribose) polymerase-1 (PARP1) inhibitors to enhance mitochondrial function. However, the underlying mechanisms have not been fully elucidated. This study investigates the impact of NMN in conjunction with PJ-34, a PARP1 inhibitor, on LPS-induced mitochondrial damage, focusing on nicotinamide mononucleotide adenylyl transferase 3 (NMNAT3) -PARP1 axis. The results showed that LPS treatment led to down-regulation of NMNAT3 (decreased 58.72% at 1 µM), up-regulation of PARP1 (enhanced 22.78% at 1 µM), thereby impairing mitophagy and mitochondrial function. The negative effects can be mitigated through supplementation with NMN and PJ-34. Specifically, compared to the LPS group, the expression of NMNAT3 increased by 63.29% and PARP1 decreased by 27.94% at a concentration of 400 µM NMN. Additionally, when 400 µM NMN was combined with 5 µM PJ-34, PARP1 expression decreased by 21.99%. Mechanistic studies reveal that NMN and PJ-34 counteracted the detrimental effects by promoting the binding of FoxO1 to the PINK1 promoter to activate the PINK1/Parkin mediated mitophagy pathway. Further experimental results demonstrate that the down-regulation of NMNAT3 can activate PARP1 and inhibit the initiation of autophagic processes. Consequently, targeting the NMNAT3-PARP1 signaling pathway holds promise for the development of novel therapeutic strategies to alleviate mitochondrial damage-related disorders.

NAD+ overconsumption by poly (ADP-ribose) polymerase (PARP) under oxidative stress induces cytoskeletal disruption in vascular endothelial cell

Vascular endothelial cytoskeletal disruption leads to increased vascular permeability and is involved in the pathogenesis and progression of various diseases. Oxidative stress can increase vascular permeability by weakening endothelial cell-to-cell junctions and decrease intracellular nicotinamide adenine dinucleotide (NAD+) levels. However, it remains unclear how intracellular NAD+ variations caused by oxidative stress alter the vascular endothelial cytoskeletal organization. In this study, we demonstrated that oxidative stress activates poly (ADP-ribose [ADPr]) polymerase (PARP), which consume large amounts of intracellular NAD+, leading to cytoskeletal disruption in vascular endothelial cells. We found that hydrogen peroxide (H2O2) could transiently disrupt the cytoskeleton and reduce intracellular total NAD levels in human umbilical vein endothelial cells (HUVECs). H2O2 stimulation led to rapid increase in ADPr protein levels in HUVECs. Pharmaceutical PARP inhibition counteracted H2O2-induced total NAD depletion and cytoskeletal disruption, suggesting that NAD+ consumption by PARP induced cytoskeletal disruption. Additionally, supplementation with nicotinamide mononucleotide (NMN), the NAD+ precursor, prevented both intracellular total NAD depletion and cytoskeletal disruption induced by H2O2 in HUVECs. Inhibition of the NAD+ salvage pathway by FK866, a nicotinamide phosphoribosyltransferase inhibitor, maintained H2O2-induced cytoskeletal disruption, suggesting that intracellular NAD+ plays a crucial role in recovery from cytoskeletal disruption. Our findings provide further insights into the potential application of PARP inhibition and NMN supplementation for the treatment and prevention of diseases involving vascular hyperpermeability.

The Role of Nicotinamide Mononucleotide Supplementation in Psoriasis Treatment

Psoriasis is one of several chronic inflammatory skin diseases with a high rate of recurrence, and its pathogenesis remains unclear. Nicotinamide mononucleotide (NMN), as an important precursor of nicotinamide adenine dinucleotide (NAD+), has been reported to be a promising agent in treating various diseases, its positive effects including those induced via its anti-inflammatory and antioxidant properties. For this reason, we have aimed to explore the possible role of NMN in the treatment of psoriasis. Psoriasis models were constructed with imiquimod (IMQ) stimulation for 5 days in vivo and with M5 treatment in keratinocyte cell lines in vitro. NMN treatment during the IMQ application period markedly attenuated excess epidermal proliferation, splenomegaly, and inflammatory responses. According to GEO databases, Sirtuin1 (SIRT1) levels significantly decreased in psoriasis patients' lesion tissues; this was also the case in the IMQ-treated mice, while NMN treatment reversed the SIRT1 decline in the mouse model. Moreover, NMN supplementation also improved the prognoses of the mice after IMQ stimulation, compared to the untreated group with elevated SIRT1 levels. In HEKa and HaCaT cells, the co-culturing of NMN and M5 significantly decreased the expression levels of proinflammation factors, the phosphorylation of NF-κB, stimulator of interferon genes (STING) levels, and reactive oxygen species levels. NMN treatment also recovered the decrease in mitochondrial membrane potential and respiration ability and reduced mtDNA in the cytoplasm, leading to the inhibition of autoimmune inflammation. The knockdown of SIRT1 in vitro eliminated the protective and therapeutic effects of NMN against M5. To conclude, our results indicate that NMN protects against IMQ-induced psoriatic inflammation, oxidative stress, and mitochondrial dysfunction by activating the SIRT1 pathway.

Mechanisms Underlying the Therapeutic Effects of Nicotinamide Mononucleotide in Treating High-fat Diet-induced Hypertrophic Cardiomyopathy based on GEO Datasets, Network Pharmacology, and Molecular Docking

BACKGROUND

The beneficial effects of nicotinamide mononucleotide (NMN) on heart disease have been reported, but the effects of NMN on high-fat diet-induced hypertrophic cardiomyopathy (HCM) and its mechanisms of action are unclear. In this study, we systematically explored the effects and mechanism of action of NMN in HCM using network pharmacology and molecular docking.

METHODS

Active targets of NMN were obtained from SWISS, CNKI, PubMed, DrugBank, BingingDB, and ZINC databases. HCM-related targets were retrieved from GEO datasets combined with GeneCards, OMIM, PharmGKB, and DisGeNET databases. A Protein-protein Interaction (PPI) network was built to screen the core targets. DAVID was used for GO and KEGG pathway enrichment analyses. The tissue and organ distribution of targets was evaluated. Interactions between potential targets and active compounds were assessed by molecular docking. A molecular dynamics simulation was conducted for the optimal core protein-compound complexes obtained by molecular docking.

RESULTS

In total, 265 active targets of NMN and 3918 potential targets of HCM were identified. A topological analysis of the PPI network revealed 10 core targets. GO and KEGG pathway enrichment analyses indicated that the effects of NMN were mediated by genes related to inflammation, apoptosis, and oxidative stress, as well as the FOXO and PI3K-Akt signaling pathways. Molecular docking and molecular dynamics simulations revealed good binding ability between the active compounds and screened targets.

CONCLUSION

The possible targets and pathways of NMN in the treatment of HCM have been successfully predicted by this investigation. It provides a novel approach for further investigation into the molecular processes of NMN in HCM treatment.

Gut Microbiota and Mitochondria: Health and Pathophysiological Aspects of Long COVID

The current understanding of long COVID (LC) is still limited. This review highlights key findings regarding the role of gut microbiota, mitochondria, and the main pathophysiological aspects of LC revealed by clinical studies, related to the complex interplay between infection, intestinal dysbiosis, dysfunctional mitochondria, and systemic inflammation generated in a vicious circle, reflecting the molecular and cellular processes from the "leaky gut" to the "leaky electron transport chain (ETC)" into a quantum leap. The heterogeneity of LC has hindered progress in deciphering all the pathophysiological mechanisms, and therefore, the approach must be multidisciplinary, with a special focus not only on symptomatic management but also on addressing the underlying health problems of the patients. It is imperative to further assess and validate the effects of COVID-19 and LC on the gut microbiome and their relationship to infections with other viral agents or pathogens. Further studies are needed to better understand LC and expand the interdisciplinary points of view that are required to accurately diagnose and effectively treat this heterogeneous condition. Given the ability of SARS-CoV-2 to induce autoimmunity in susceptible patients, they should be monitored for symptoms of autoimmune disease after contracting the viral infection. One question remains open, namely, whether the various vaccines developed to end the pandemic will also induce autoimmunity. Recent data highlighted in this review have revealed that the persistence of SARS-CoV-2 and dysfunctional mitochondria in organs such as the heart and, to a lesser extent, the kidneys, liver, and lymph nodes, long after the organism has been able to clear the virus from the lungs, could be an explanation for LC.