Varga, John

ABSTRACT Nicotinamide adenine dinucleotide (NAD) is a key coenzyme involved in energy metabolism, DNA repair, and cellular signaling. While the effects of acute NAD depletion have been better characterized, the consequences of chronic NAD deficiency remain unclear. Here, we investigated the impact of chronic NAD depletion in cultured cells by removing the availability of nicotinamide (NAM), a key precursor for NAD synthesis, from the culture media. In NIH3T3 fibroblasts, NAM depletion caused a dramatic drop in intracellular NAD levels within 2 days. Remarkably, the cells remained viable even after 7–14 days of NAM depletion, despite NAD + levels falling to less than 10% of control conditions. This chronic NAD depletion led to distinct metabolic alterations. Mitochondrial basal respiration remained unchanged, but cells exhibited reduced spare respiratory and maximal capacities, along with significantly impaired glycolysis. Notably, NAD depletion triggered an interferon‐dependent inflammatory response, resembling viral infections. This was driven by cytosolic leakage of mitochondrial DNA (mtDNA) through voltage‐dependent anion channel 1 (VDAC1), which activated the cGAS‐STING signaling pathway. Inhibition of VDAC oligomerization with VBIT‐4, STING signaling with H‐151, or mtDNA depletion blocked the upregulation of interferon genes induced by NAM depletion. Similar interferon responses triggered by NAD depletion were observed in IMR90 human fibroblasts and HS5 stromal cells. Our findings reveal a novel link between chronic NAD deficiency, VDAC‐mediated mtDNA release to the cytoplasm, and the activation of the inflammatory response, providing new insight into how NAD decline affects cellular metabolic and inflammatory processes.

Objective We provide evidence‐based recommendations regarding the treatment of interstitial lung disease (ILD) in adults with systemic autoimmune rheumatic diseases (SARDs). Methods We developed clinically relevant population, intervention, comparator, and outcomes questions. A systematic literature review was then performed, and the available evidence was rated using the Grading of Recommendations, Assessment, Development, and Evaluation methodology. A panel of clinicians and patients reached consensus on the direction and strength of the recommendations. Results Thirty‐five recommendations were generated (including two strong recommendations) for first‐line SARD‐ILD treatment, treatment of SARD‐ILD progression despite first‐line ILD therapy, and treatment of rapidly progressive ILD. The strong recommendations were against using glucocorticoids in systemic sclerosis–ILD as a first‐line ILD therapy and after ILD progression. Otherwise, glucocorticoids are conditionally recommended for first‐line ILD treatment in all other SARDs. Conclusion This clinical practice guideline presents the first recommendations endorsed by the American College of Rheumatology and American College of Chest Physicians for the treatment of ILD in people with SARDs.

ObjectiveWe provide evidence‐based recommendations regarding screening for interstitial lung disease (ILD) and the monitoring for ILD progression in people with systemic autoimmune rheumatic diseases (SARDs), specifically rheumatoid arthritis, systemic sclerosis, idiopathic inflammatory myopathies, mixed connective tissue disease, and Sjögren disease.MethodsWe developed clinically relevant population, intervention, comparator, and outcomes questions related to screening and monitoring for ILD in patients with SARDs. A systematic literature review was performed, and the available evidence was rated using the Grading of Recommendations, Assessment, Development, and Evaluation methodology. A Voting Panel of interdisciplinary clinician experts and patients achieved consensus on the direction and strength of each recommendation.ResultsFifteen recommendations were developed. For screening people with these SARDs at risk for ILD, we conditionally recommend pulmonary function tests (PFTs) and high‐resolution computed tomography of the chest (HRCT chest); conditionally recommend against screening with 6‐minute walk test distance (6MWD), chest radiography, ambulatory desaturation testing, or bronchoscopy; and strongly recommend against screening with surgical lung biopsy. We conditionally recommend monitoring ILD with PFTs, HRCT chest, and ambulatory desaturation testing and conditionally recommend against monitoring with 6MWD, chest radiography, or bronchoscopy. We provide guidance on ILD risk factors and suggestions on frequency of testing to evaluate for the development of ILD in people with SARDs.ConclusionThis clinical practice guideline presents the first recommendations endorsed by the American College of Rheumatology and American College of Chest Physicians for the screening and monitoring of ILD in people with SARDs.

Objective We provide evidence‐based recommendations regarding screening for interstitial lung disease (ILD) and the monitoring for ILD progression in people with systemic autoimmune rheumatic diseases (SARDs), specifically rheumatoid arthritis, systemic sclerosis, idiopathic inflammatory myopathies, mixed connective tissue disease, and Sjögren disease. Methods We developed clinically relevant population, intervention, comparator, and outcomes questions related to screening and monitoring for ILD in patients with SARDs. A systematic literature review was performed, and the available evidence was rated using the Grading of Recommendations, Assessment, Development, and Evaluation methodology. A Voting Panel of interdisciplinary clinician experts and patients achieved consensus on the direction and strength of each recommendation. Results Fifteen recommendations were developed. For screening people with these SARDs at risk for ILD, we conditionally recommend pulmonary function tests (PFTs) and high‐resolution computed tomography of the chest (HRCT chest); conditionally recommend against screening with 6‐minute walk test distance (6MWD), chest radiography, ambulatory desaturation testing, or bronchoscopy; and strongly recommend against screening with surgical lung biopsy. We conditionally recommend monitoring ILD with PFTs, HRCT chest, and ambulatory desaturation testing and conditionally recommend against monitoring with 6MWD, chest radiography, or bronchoscopy. We provide guidance on ILD risk factors and suggestions on frequency of testing to evaluate for the development of ILD in people with SARDs. Conclusion This clinical practice guideline presents the first recommendations endorsed by the American College of Rheumatology and American College of Chest Physicians for the screening and monitoring of ILD in people with SARDs.

Purpose of review Here we review recent literature on the emerging role of nicotinamide adenine dinucleotide (NAD + ) metabolism and its dysfunction via the enzyme CD38 in the pathogenesis of rheumatologic diseases. We evaluate the potential of targeting CD38 to ameliorate NAD + -related metabolic imbalance and tissue dysfunction in the treatment of systemic sclerosis (SSc), systemic lupus erythematous (SLE), and rheumatoid arthritis (RA). Recent findings In this review, we will discuss emerging basic, preclinical, and human data that point to the novel role of CD38 in dysregulated NAD + -homeostasis in SSc, SLE, and RA. In particular, recent studies implicate increased activity of CD38, one of the main enzymes in NAD + catabolism, in the pathogenesis of persistent systemic fibrosis in SSc, and increased susceptibility of SLE patients to infections. We will also discuss recent studies that demonstrate that a cytotoxic CD38 antibody can promote clearance of plasma cells involved in the generation of RA antibodies. Summary Recent studies identify potential therapeutic approaches for boosting NAD + to treat rheumatologic diseases including SSc, RA, and SLE, with particular attention to inhibition of CD38 enzymatic activity as a target. Key future directions in the field include the determination of the cell-type specificity and role of CD38 enzymatic activity versus CD38 structural roles in human diseases, as well as the indicators and potential side effects of CD38-targeted treatments.