NAD⁺ biosynthesis and mitochondrial repair in acute kidney injury via ultrasound-responsive thylakoid-integrating liposomes

Acute kidney injury (AKI) impairs the energy metabolism and antioxidant capacity of renal proximal tubular cells. Here we show that ultrasound-responsive liposomes integrating thylakoid fragments and encapsulating l-ascorbic acid can restore the energy supply and antioxidant capacity of the tubular cells as well as renal function in animal models of AKI. After intravenous injection, the liposomes preferentially accumulated in the injured kidneys and were internalized by proximal tubular cells. Quinolinate phosphoribosyltransferase expressed in thylakoid catalysed the biosynthesis of nicotinamide adenine dinucleotide (NAD⁺), prompting the recovery of damaged mitochondria. Local ultrasound stimulation activated electron transfer from ascorbic acid, which led to the cytoplasmic formation of NADH and to the restoration of adenosine triphosphate through the malate-aspartate shuttle. Concurrently, the enhanced pentose phosphate pathway facilitated NADPH biosynthesis and reduced the levels of reactive oxygen species. In mice and piglets with AKI, low doses of the liposomes prevented kidney damage.