title: Synthesis and evaluation of human serum albumin-modified exendin-4 conjugate via heterobifunctional polyethylene glycol linkage with protracted hypoglycemic efficacy.
abstract: Albumin conjugation is considered to be one of the most effective means of protracting the short in vivo lifespans of peptides and proteins. Here, we present a new long-acting antidiabetic exendin-4 conjugate linked with human serum albumin (HSA) via polyethylene glycol (PEG). As a first step toward synthesizing this conjugate, three artificial sulfhydryl groups were introduced in HSA using 2-iminothiolane at pH 8.0. This thiolated HSA was further reacted with the monomer fraction of exendin-4 (6 equiv) conjugated with maleimide-PEG(5k)-N- hydroxysuccinimide (MAL-PEG(5k)-NHS) for 3 h. Because of the presence of PEG molecules, the resulting conjugate (HSA-PEG-Ex4) was found to have a greater apparent molecular weight and a larger particle size (ca. 195 kDa and 9.48 +/- 0.74 nm) than those of HSA-exendin-4 without the PEG linker (HSA-Ex4, ca. 84.3 kDa and 7.77 +/- 0.98 nm). Although the receptor binding affinity of HSA-PEG-Ex4 on RIN-m5F cells was significantly lower than that of Ex4, its antihyperglycemic efficacy was slightly higher than that of Ex-4 and HSA-Ex4 in type 2 diabetic db/db mice. Furthermore, HSA-PEG-Ex4 had greater circulating t(1/2) and AUC(inf) values than HSA-Ex and native exendin-4 by 2.1- and 10.3-fold, respectively. Accordingly, its hypoglycemic duration was greatly increased to 31.0 h at a dose of 250 nmol/kg vs that of native Ex4 (7.0 h). Results show that the HSA-PEG-Ex4 conjugate produced has distinct advantages over HSA-Ex4 without PEG. We believe that this exendin-4 derivative, which has the merits of albumin conjugation and PEGylation, has considerable potential as a novel type 2 antidiabetic agent.
authors: Pusan National University, 30 Jangjun-dong, Geumjeong-gu, Busan, Korea. [corrected]
authors: Insoo
authors: I
authors: Kim
authors: Tae Hyung
authors: TH
authors: Kim
authors: Kyungwan
authors: K
authors: Ma
authors: Eun Seong
authors: ES
authors: Lee
authors: Dongin
authors: D
authors: Kim
authors: Kyung Taek
authors: KT
authors: Oh
authors: Don Haeng
authors: DH
authors: Lee
authors: Kang Choon
authors: KC
authors: Lee
authors: Yu Seok
authors: YS
authors: Youn
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D000077270:Exenatide; D005951:Glucose Tolerance Test; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000188:drug therapy*; D007004:Hypoglycemic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use*; D008297:Male; D008301:Maleimides / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D015394:Molecular Structure; D008970:Molecular Weight; D010316:Particle Size; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use*; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D012709:Serum Albumin / Q000737:chemistry*; D013388:Succinimides / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties; D014688:Venoms / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use*
chemical_list: D007004:Hypoglycemic Agents; D008301:Maleimides; D010455:Peptides; D012709:Serum Albumin; D013388:Succinimides; D013438:Sulfhydryl Compounds; D014688:Venoms; C043592:maleimide; D011092:Polyethylene Glycols; D000077270:Exenatide; C001426:N-hydroxysuccinimide