Selection of a Full Agonist Combinatorial Antibody that Rescues Leptin Deficiency In Vivo

Abstract

Growth factor deficiency in adulthood constitutes a distinct clinical syndrome with significant morbidities including abnormal body composition, reduced energy, affective disturbances, dyslipidemia, and increased cardiovascular risk. Protein replacement therapies using recombinant proteins or enzymes represent the only approved treatment. Combinatorial antibodies have shown great promise as a new class of therapeutic molecules because they act as “mechanism‐based antibodies” with both agonist and antagonist activities. Using leptin, a key hormone in energy metabolism, as an example, a function‐guided approach is developed to select combinatorial antibodies with high potency and full agonist activity that substitute natural growth factors in vivo. The identified antibody shows identical biochemical properties and cellular profiles as leptin, and rescues leptin‐deficiency in ob/ob mice. Remarkably, the antibody activates leptin receptors that are otherwise nonfunctional because of mutations (L372A and A409E). Combinatorial antibodies have significant advantages over recombinant proteins for chronical usage in terms of immunological tolerance and biological stability.

Structural insights into the mechanism of leptin receptor activation

“…2e ), consistent with JAK2 homodimerization driving downstream LepR signaling 5 , 13 , 41 , 42 . Moreover, engineered antibodies that induce LepR homodimerization independently of leptin have been shown to exert full agonist activity, suggesting recruitment of two copies of LepR is sufficient for full receptor activation 43 . The open 2:2 architecture observed here therefore likely represents the minimal fully active LepR signaling complex, and the functional role of the symmetric 3:3 assembly remains to be determined.…”

A Historical Review of Brain Drug Delivery

“…Leptin receptor (LEPR) antibodies are yet to be tested as BBB RMT agents. A panel of antibodies against the human LRPR ECD was isolated by panning a single chain Fv (ScFv) phage library with the human LEPR ECD [705]. For isolation of a LEPR antibody that does not inhibit leptin binding to the LEPR, panning of phage libraries can be performed with complexes of the LEPR ECD and leptin so as to eliminate capture of antibodies that bind the leptin binding site on the LEPR.…”

Obesity modulates cell-cell interactions during ovarian folliculogenesis

“…We first used two widely corroborated genetic models, leptin knockout (Lep KO) and leptinreceptor knockout (Lepr KO) mice (Figure S1A). Due to leptin deficiency in Lep KO mice or leptin receptor loss-of-function in Lepr KO mice, these two mouse lines developed severe hyperphagia and spontaneous obesity, accompanying the resulting metabolic disorders including insulin-resistance and impaired glucose homeostasis (Chen et al, 2021;Jia et al, 2020;Pan et al, 2021;Tao et al, 2020;Zheng et al, 2021aZheng et al, , 2021b. We also used high-fat diet feeding to obtain HFD mice (Figure S1B).…”