Polymyxin nephrotoxicity in kidney chip

Drug-induced kidney injury, largely caused by proximal tubular intoxicants, limits development and clinical use of new and approved drugs. Assessing preclinical nephrotoxicity relies on animal models that are frequently insensitive, and thus, novel techniques, including human microphysiological systems, or “organs on chips,” are proposed to accelerate drug development and predict safety. Polymyxins are potent antibiotics against multidrug-resistant microorganisms; yet clinical use remains restricted because of high risk of nephrotoxicity and limited understanding of toxicological mechanisms. To mitigate risks, structural analogs of polymyxins (NAB739 and NAB741) are currently in clinical development. Using a microphysiological system to model human kidney proximal tubule, we exposed cells to polymyxin B (PMB) and observed significant increases of injury signals, including kidney injury molecule-1 KIM-1and a panel of injury-associated miRNAs (each P < 0.001). Surprisingly, transcriptional profiling identified cholesterol biosynthesis as the primary cellular pathway induced by PMB (P = 1.2 ×10–16), and effluent cholesterol concentrations were significantly increased after exposure (P < 0.01). Additionally, we observed no upregulation of the nuclear factor (erythroid derived-2)–like 2 pathway despite this being a common pathway upregulated in response to proximal tubule toxicants. In contrast with PMB exposure, minimal changes in gene expression, injury biomarkers, and cholesterol concentrations were observed in response to NAB739 and NAB741. Our findings demonstrate the preclinical safety of NAB739 and NAB741 and reveal cholesterol biosynthesis as the novel (to our knowledge) pathway for PMB- induced injury. To our knowledge, this is the first demonstration of a human-on-chip platform used for simultaneous safety testing of new chemical entities and defining unique toxicological pathway responses of an FDA-approved molecule. Overall design: Cells from six donors were seeded into a total of 74 kidney chips, and effluents of kidney MPS were exposed for 48 hours of treatments

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Weber EJ, Lidberg KA, Wang L, Bammler TK, MacDonald JW, Li MJ, Redhair M, Atkins WM, Tran C, Hines KM, Herron J, Xu L, Monteiro MB, Ramm S, Vaidya V, Vaara M, Vaara T, Himmelfarb J, Kelly EJ