DHHC21 Deficiency Attenuates Renal Dysfunction During Septic Injury

Abstract

Renal dysfunction is one of the most common complications of septic injury. One critical contributor to septic injury-induced renal dysfunction is renal vascular dysfunction. Protein palmitoylation serves as a novel regulator of vascular function. Here, we examined whether palmitoyl acyltransferase (PAT)-DHHC21 contributes to septic injury-induced renal dysfunction through regulating renal hemodynamics. Multispectral optoacoustic imaging showed that cecal ligation and puncture (CLP)-induced septic injury caused impaired renal excretion, which was improved in DHHC21 functional deficient (Zdhhc21dep/dep) mice. DHHC21 deficiency attenuated CLP-induced renal pathology, characterized by tissue structural damage and circulating injury markers. Importantly, DHHC21 loss-of-function led to better-preserved renal perfusion and oxygen saturation after CLP. The CLP-caused reduction in renal blood flow was also ameliorated in Zdhhc21dep/dep mice. Next, CLP promoted the palmitoylation of vascular α1-adrenergic receptor (α1AR) and the activation of its downstream effector ERK, which were blunted in Zdhhc21dep/dep mice. Vasoreactivity analysis revealed that renal arteries from Zdhhc21dep/dep mice displayed reduced constriction response to α1AR agonist phenylephrine compared to those from wild-type mice. Consistently, inhibiting PATs with 2-bromopalmitate caused a blunted vasoconstriction response to phenylephrine in small arteries isolated from human kidneys. Therefore, DHHC21 contributes to impaired renal perfusion and function during septic injury via promoting α1AR palmitoylation-associated vasoconstriction.

Protein palmitoylation regulates extracellular vesicle production and function in sepsis

“…In recent studies, we identified a significantly increased plasma level of EVs in patients and animals with trauma and sepsis, correlating with exacerbated proinflammatory response and cellular injury (Beard et al., 2016). We also observed greatly increased palmitoylation and DHHC21 activity under inflammatory conditions (Beard et al., 2016; Yang et al., 2021). DHHC21, unlike other DHHCs, is localized in plasma membrane, which allows it to dynamically regulate the function of many plasma membrane‐associated proteins involved in EV generation, such as G protein‐coupled receptors, G proteins, and phospholipases (Beard et al., 2016; Fan et al., 2020; Yang et al., 2021).…”

“…Palmitoylated proteins on EVs were isolated using resin‐assisted capture as previously described (Beard et al., 2016; Mariscal et al., 2020; Yang et al., 2021). EV samples were lysed in lysis buffer (100 mM HEPES, 25 mM NaCl, 1 mM EDTA, 10 μM palmostatin B, Roche protease inhibitor tablet, pH 7.4).…”

“…We also observed greatly increased palmitoylation and DHHC21 activity under inflammatory conditions (Beard et al, 2016;Yang et al, 2021). DHHC21, unlike other DHHCs, is localized in plasma membrane, which allows it to dynamically regulate the function of many plasma membrane-associated proteins involved in EV generation, such as G protein-coupled receptors, G proteins, and phospholipases (Beard et al, 2016;Fan et al, 2020;Yang et al, 2021). In the present study, we sought to determine if DHHC21-mediated palmitoylation affects EV production, cargo content, and function during sepsis.…”

“…Zdhhc dep/dep mice and their wild-type control mice (B6C3Fe) were purchased from Jackson Laboratory. The genotype and phenotype of Zdhhc dep/dep mice were reported in our previous publications (Beard et al, 2016;Yang et al, 2021). Mice were housed under a 12/12 h light/dark cycle with food and water available ad libitum.…”

How palmitoylation affects trafficking and signaling of membrane receptors

“…It is indeed not clear whether β1-AR is palmitoylated on C358 only (Warne et al, 2009), or also on C392, C393, and C414 (Zuckerman et al, 2011) (Figure 2a). Two groups observed that DHHC21 is responsible for β1-AR palmitoylation (Marin et al, 2016;Yang et al, 2021). DHHC21 essentially localizes to the Golgi apparatus (Chopard et al, 2018;Fernández-Hernando et al, 2006;Tonn Eisinger et al, 2018).…”