A Therapeutic Dose of Lithium Triggers Anti-inflammatory Mechanisms in The Kidneys of Treated Mice
Authors: Baranovskaya Irina , Volk Kevin , Alexander Sati , Mumuney Nichole , Abais-Battad Justine , Mamenko Mykola 
Published: May 2024

Lithium (Li+) is an effective mood stabilizer in people with schizoaffective disorders with more than 2 million prescriptions per year. Accumulation of Li+ in blood can cause neprotoxicity, manifesting in nephrogenic diabetes insipidus, renal tubular acidosis and tubulointerstitial nephropathy. Damage to renal cells often leads to a local immune response, playing a pivotal role in the ensuing renal injury and subsequent recovery. While both pro- and anti-inflammatory actions of Li+ were reported in various tissues, our understanding of the immunomodulatory effects of Li+ in the kidney is fragmentary. Here, we studied how immune mechanisms contribute to the development of Li+-induced adverse effects in the kidneys of C57BL/6 mice receiving a 0.3% lithium carbonate diet for 28 days. Given the insidious development of Li+-induced renal injury, we hypothesize that nephrotoxic effects of Li+ are alleviated by its anti-inflammatory action. We used fluorescence-activated cell sorting, qPCR, immunoblotting and proteome profiler arrays to assess the pyroptotic inflammatory cascade, characterize the infiltrating immune cells and cytokine markers in the renal tissue isolated from Li+-treated and control mice. We found that both biomarkers of tubular damage, kidney injury marker, KIM-1, and neutrophil gelatinase-associated lipocalin, NGAL, are elevated in the renal tissue of Li+-treated mice. This correlated with a moderate but significant increase in renal fibrosis in mice on Li+ diet. Expression of most genes associated with pyroptotic inflammatory cascade, including NLRP3, Casp-1, IL-1b, was not different in the renal tissue isolated from control and Li+-treated mice. Higher mRNA levels of apoptosis-associated speck-like protein (ASC), in the renal tissue of Li+-treated mice could be attributed to its a pro-apoptotic, rather than inflammasome forming, function. This is in line with elevated levels of CD93 marker in the kidneys of mice on Li+ diet, reflecting increased clearance of apoptotic cells. In general, Li+-treated mice had markedly higher levels of anti-inflammatory cytokine markers in the renal tissue, most notably, IL-10 and adiponectin, and lower abundance of pro-inflammatory markers, such as CD26, CLCX16, PCSK9 and osteopontin. Higher abundance of proinflammatory IL-6 in the kidneys of Li+-treated mice made a notable exception. However, this cytokine can also be released by tubular epithelial cells under insult and induce polarization of anti-inflammatory M2 macrophages. Mice on Li+-diet had higher levels of macrophages (F4.80+ cells) in the renal tissue. Future studies will determine their polarization phenotype. Overall, our results suggest that Li+-induced toxic insult to the tubular epithelial cells is paralleled by the anti-inflammatory immune response localized to the renal tissue. NIDDK 1R01DK125464. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.