In search for new antipsoriatic agents: NAD topical composition

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.

Assessment of NADH/NAD+ Redox Imbalance in Psoriatic Lesions Using the FMSF Technique: Therapeutic Aspects

Mitochondrial dysfunction has been linked to psoriasis, and it may be an important underlying factor contributing to this disease. However, a precise methodology for assessing mitochondrial dysfunction has yet to be developed. One promising approach is to measure NADH autofluorescence from the affected skin areas. In this study, we show that Flow-Mediated Skin Fluorescence (FMSF) can be used for the non-invasive assessment of mitochondrial dysfunction in psoriasis. The fluorescence level at baseline and the half-time of ischemic growth (t1/2) derived from the FMSF traces can be used for the non-invasive assessment of NADH/NAD+ redox imbalance in psoriatic lesions compared to unaffected skin. These results are supported by an analysis of the key FMSF parameters: Reactive Hyperemia Response (RHR) and Hypoxia Sensitivity (HS). This method not only contributes to understanding the biochemical processes involved in the etiopathogenesis of psoriasis, but it also provides a basis for identifying new drug targets and improving the treatment process.

Nicotinamide adenine dinucleotide metabolism in the immune response, autoimmunity and inflammageing

Metabolism is dynamically regulated to accompany immune cell function, and altered immunometabolism can result in impaired immune responses. Concomitantly, the pharmacological manipulation of metabolic processes offers an opportunity for therapeutic intervention in inflammatory disorders. The nicotinamide adenine dinucleotide (NAD⁺) is a critical metabolic intermediate that serves as enzyme cofactor in redox reactions, and is also used as a co‐substrate by many enzymes such as sirtuins, adenosine diphosphate ribose transferases and synthases. Through these activities, NAD⁺ metabolism regulates a broad spectrum of cellular functions such as energy metabolism, DNA repair, regulation of the epigenetic landscape and inflammation. Thus, the manipulation of NAD⁺ availability using pharmacological compounds such as NAD⁺ precursors can have immune‐modulatory properties in inflammation. Here, we discuss how the NAD⁺ metabolism contributes to the immune response and inflammatory conditions, with a special focus on multiple sclerosis, inflammatory bowel diseases and inflammageing.

Clinical Evidence for Targeting NAD Therapeutically

Nicotinamide adenine dinucleotide (NAD) pharmacology is a promising class of treatments for age-related conditions that are likely to have a favorable side effect profile for human use, given the widespread use of the NAD precursor vitamin B3 supplements. However, despite several decades of active investigation and numerous possible biochemical mechanisms of action suggested, only a small number of randomized and adequately powered clinical trials of NAD upregulation as a therapeutic strategy have taken place. We conducted a systematic review of the literature, following the PRISMA guidelines, in an attempt to determine whether or not the human clinical trials performed to date support the potential benefits of NAD supplementation in a range of skin, metabolic and age-related conditions. In addition, we sought medical indications that have yielded the most promising results in the limited studies to date. We conclude that promising, yet still speculative, results have been reported for the treatment of psoriasis and enhancement of skeletal muscle activity. However, further trials are required to determine the optimal method of raising NAD levels, identifying the target conditions, and comparisons to the present standard of care for these conditions. Lastly, pharmacological methods that increase NAD levels should also be directly compared to physiological means of raising NAD levels, such as exercise programs and dietary interventions that are tailored to older individuals, and which may be more effective.

Methotrexate use and NAD+/NADH metabolism in psoriatic keratinocytes

Methotrexate inhibits tetrahydrofolic acid production and influences mitochondrial oxygen uptake and activity of several enzymes in the respiratory chain reactions, which utilize nicotinamide adenine dinucleotide-linked (NAD-linked) substrates. Hyperproliferation of keratinocytes in psoriasis requires oxidative phosphorylation, in which the reduced form of nicotinamide adenine dinucleotide (NADH) is an electron donor. One hypothesis links increased cellular metabolism to the increased NADH/NAD⁺ ratio; as expected, the topical application of NAD⁺ (oxidized form of nicotinamide-adenine dinucleotide) resulted in a clinical improvement of psoriatic lesions in one study. Nevertheless, another report revealed reduced fluorescence of NADH in psoriatic plaques. The biological activity of NADH is not limited only to serving as the electron donor. It was also found to regulate gene transcription.

NAD+ therapy in age-related degenerative disorders: A benefit/risk analysis

Nicotinamide adenine dinucleotide (NAD+) is an essential pyridine nucleotide that is present in all living cells. NAD+ acts as an important cofactor and substrate for a multitude of biological processes including energy production, DNA repair, gene expression, calcium-dependent secondary messenger signalling and immunoregulatory roles. The de novo synthesis of NAD+ is primarily dependent on the kynurenine pathway (KP), although NAD+ can also be recycled from nicotinic acid (NA), nicotinamide (NAM) and nicotinamide riboside (NR). NAD+ levels have been reported to decline during ageing and age-related diseases. Recent studies have shown that raising intracellular NAD+ levels represents a promising therapeutic strategy for age-associated degenerative diseases in general and to extend lifespan in small animal models. A systematic review of the literature available on Medline, Embase and Pubmed was undertaken to evaluate the potential health and/or longevity benefits due to increasing NAD+ levels. A total of 1545 articles were identified and 147 articles (113 preclinical and 34 clinical) met criteria for inclusion. Most studies indicated that the NAD+ precursors NAM, NR, nicotinamide mononucleotide (NMN), and to a lesser extent NAD+ and NADH had a favourable outcome on several age-related disorders associated with the accumulation of chronic oxidative stress, inflammation and impaired mitochondrial function. While these compounds presented with a limited acute toxicity profile, evidence is still quite limited and long-term human clinical trials are still nascent in the current literature. Potential risks in raising NAD+ levels in various clinical disorders using NAD+ precursors include the accumulation of putative toxic metabolites, tumorigenesis and promotion of cellular senescence. Therefore, NAD+ metabolism represents a promising target and further studies are needed to recapitulate the preclinical benefits in human clinical trials.

1-Methylnicotinamide and nicotinamide: two related anti-inflammatory agents that differentially affect the functions of activated macrophages

INTRODUCTION

1-Methylnicotinamide (MNA), a major metabolite of nicotinamide (NA), is known to exert anti-inflammatory effects in vivo. Treatment of inflammatory skin diseases by topical application of MNA provides certain advantages over the use of NA. However, in contrast to NA, the molecular mechanisms of the anti-inflammatory properties of MNA are not well known. In this study the influence of exogenous MNA and NA in vivo on the generation of inflammatory mediators by macrophages (Mvarphi) was investigated.

MATERIALS AND METHODS

Peritoneal Mvarphi of CBA/J mice were activated in vitro with lipopolysaccharide and incubated with MNA or NA. The effect of these compounds on biological functions of Mvarphi was measured by evaluation of the production of reactive oxygen species (ROS) by luminol-dependent chemiluminescence, cytokines and prostaglandin E(2) (PGE(2)) by ELISA, and nitric oxide (NO) by the Griess method. Moreover, the expressions of inducible NO synthase and cyclooxygenase-2 were measured by Western blotting.

RESULTS

It was shown that at non-cytotoxic concentrations, NA inhibits the production of a variety of pro-inflammatory agents, such as tumor necrosis factor alpha, interleukin 6, NO, PGE(2), and the generation of ROS. In contrast to NA, exogenous MNA inhibited only the generation of ROS, while its effect on the synthesis of other mediators was negligible.

CONCLUSIONS

These results indicate that the anti-inflammatory properties of MNA demonstrated previously in vivo do not depend on its capacity to suppress the functions of immune cells, but more likely may be related to its action on vascular endothelium. The authors suggest that the limited permeability for exogenous MNA, in contrast to that for NA, may be responsible for its lack of suppressor activity against Mvarphi.