Liver-Specific Nonviral Gene Delivery of Fibroblast Growth Factor 21 Protein Expression in Mice Regulates Body Mass and White/Brown Fat Respiration

Abstract

Viral-mediated in vivo gene delivery methods currently dominate among therapeutic strategies within the clinical and experimental settings, albeit with well documented limitations arising from immunologic constraints. In this study, we demonstrate the utility of nonviral hepatotropic in vivo gene delivery of unpackaged expression constructs, including one encoding fibroblast growth factor 21 (FGF21). FGF21 is an important hepatokine whose expression positively correlates with therapeutic outcomes across various animal models of obesity. Our data demonstrate that FGF21 expression can be restored into the livers of immunocompetent FGF21 knockout mice for at least 2 weeks after a single injection with an FGF21 expression plasmid. In wild-type C57BL6/J mice, in vivo transfection with an FGF21-expressing plasmid induced weight loss, decreased adiposity, and activated thermogenesis in white fat within 2 weeks. Furthermore, in vivo FGF21 gene delivery protected C57BL6/J mice against diet-induced obesity by decreasing adiposity and increasing uncoupling protein 1–dependent thermogenesis in brown fat and by boosting respiratory capacity in subcutaneous and perigonadal white fat. Together, the data illustrate a facile and effective methodology for delivering prolonged protein expression specifically to the liver. We contend that this method will find utility in basic science research as a practical means to enhance in vivo studies characterizing liver protein function. We further believe our data provide a rationale for further exploring the potential clinical utility of nonviral gene therapy in mouse models of disease. Significance Statement This study presents a valuable method for nonviral gene delivery in mice that improves upon existing techniques. The data provide a rationale for further exploring the potential clinical utility of nonviral gene therapy in mouse models of disease and will likely enhance in vivo studies characterizing liver protein function.

Fibroblast growth factor 21: An emerging pleiotropic regulator of lipid metabolism and the metabolic network

“… 85 Although viral-mediated in vivo gene delivery can produce significant effects and is widely used, nonviral-mediated FGF21 expression plasmids can also be used for adipose cell transfection into the liver, providing new ideas and a basis for basic research even if the transfection time is increased. 86 Subsequently, another interesting study proved that the transduction of the exogenous FGF21 gene into high-fat-induced obesity mice by genetic engineering technology could effectively prevent fat accumulation, inhibit the formation of fatty liver, and greatly ameliorate insulin resistance. 87 Many studies have also proven that exogenous FGF21 has an excellent effect on lipid metabolism, the homeostasis of insulin, and energy balance.…”

Targeting FGF21 in cardiovascular and metabolic diseases: from mechanism to medicine

“…Studies that investigated T2DM and FGF21 found that FGF21 can improve glucose homeostasis-related risk factors, such as glycated hemoglobin glycosylated hemoglobin A1c [142], insulin [97], and insulin resistance [108]. For obese animals and patients, preclinical and clinical trials have indicated the effect of FGF21 on improving the serum lipid profile and reducing body weight [173][174][175]. Regarding CVD, FGF21 can reduce the risk factors that influence the pathologic process of CVD, such as atherosclerosis [214], arterial stiffness [113], and blood pressure [86].…”

“…Many studies have chosen to increase FGF21 expression through genetic plasmids. One study reported that injection with a liver-specific FGF21 expression nonviral plasmid in FGF21 knockout mice can restore FGF21 expression and regulate body mass 174 . Another study utilized an adeno-associated viral vector to express FGF21 in mouse visceral adipose tissue, which resulted in reduced whole-body adiposity and adipose tissue macrophage inflammation 130 .…”