Biology subjects

Gunawan, A. L.

Publications and source records attributed to Gunawan, A. L..

3 recordsLinked to original sources

bioRxiv2026

Browning Lipid Nanoparticles Deliver Metabolic Benefits via Transient Conversion of White Adipose Tissue

Therapeutic strategies based on increasing uncoupled respiration (browning) in white adipose tissue (WAT) have great potential for treating obesity-related disorders such as diabetes and steatotic liver disease, but have not had a clinical impact because safe and efficient methods for browning WAT have not been developed. Lipid nanoparticles (LNPs) offer a promising platform for adipose-directed siRNA delivery; however, conventional formulations often exhibit limited activity in adipocytes and can induce inflammatory responses that may restrict repeated administration. Here we demonstrate that LNPs that contain ionizable lipids with three lipid tails and siRNAs targeting TLE3 and ZFP423 can efficiently transfect mature adipocytes and induce browning of WAT in vitro and in vivo while providing the biocompatibility needed for repeated subcutaneous injections. Repeated local administration of BLNPs in diet-induced obese mice resulted in sustained target gene silencing, increased expression of thermogenic markers, altered energy metabolism, and decreased hepatic lipid accumulation despite minimal effects on body weight relative to scramble siRNA controls. Collectively, these findings establish BLNPs as a promising platform for adipose-directed RNA delivery and targeted modulation of thermogenic pathways, providing a strategy for investigating how localized adipose tissue remodeling influences metabolic physiology.

bioengineering↗

bioRxiv2026

Chiral methionine oxidation reagents reveal stereospecific proteome modifications

Life is predicated on chirality, a molecular asymmetry akin to the left and right versions of human hands. Here we show that privileged protein residues are predisposed for chiral regulation. We developed enantiomeric oxaziridine reagents that systematically identify pro-(S) and pro-(R) methionine oxidation sites across proteomes that can be erased by stereospecific methionine sulfoxide reductase enzymes A and B, respectively. These probes reveal that chiral regulation of methionine oxidation-reduction processes can allosterically regulate protein function, as shown in cell and murine models of oxidative stress where selective (R)-methionine sulfoxide formation on M69 of biphenyl hydrolase-like protein leads to hydrolase inhibition and amplification of proteome N-homocysteinylation modifications. This work introduces a platform for characterizing sites of asymmetric methionine oxidation and the functional consequences concomitant with an individual chiral single-atom modification.

biochemistry↗

bioRxiv2022

Coenzyme Q regulates UCP1 expression and thermogenesis through the integrated stress responses

Coenzyme Q (CoQ) is an essential component of mitochondrial respiration1 and required for thermogenic activity in brown adipose tissues2 (BAT). CoQ deficiency leads to a wide range of pathological manifestations3 but mechanistic consequences of CoQ deficiency in specific tissues such as BAT remain poorly understood. Here we show that pharmacological or genetic CoQ deficiency (50-75% reduction) in BAT leads to accumulation of cytosolic mitochondrial RNAs (mtRNAs) and activation of the eIF2 kinase PKR resulting in the induction of the integrated stress response (ISR) and suppression of UCP1 expression in an ATF4-dependent fashion. Surprisingly, despite diminished UCP1 levels, BAT CoQ deficiency increases whole-body metabolic rates at room temperature and thermoneutrality resulting in decreased weight gain on high fat diets (HFD). This mitohormesis like effect of BAT CoQ insufficiency is dependent on the ATF4-FGF21 axis in BAT revealing an unexpected role for CoQ in the modulation of whole-body energy expenditure with wide-ranging implications for primary and secondary CoQ deficiencies.

cell biology↗