The Influence of a KDT501, a Novel Isohumulone, on Adipocyte Function in Humans

Abstract

Objective: In a phase II clinical trial in nine obese, insulin-resistant humans, we observed that treatment with KDT501, a novel isohumulone drug, increased total and high-molecular weight (HMW) adiponectin in plasma. The objective was to determine whether KDT501 increased adiponectin secretion from subcutaneous white adipose tissue (SC WAT) and the underlying mechanism(s).

Methods: Nine obese participants with either prediabetes or with normal glucose tolerance plus three features of metabolic syndrome were part of the study. SC WAT biopsies were performed before and after 28 days of KDT501 treatment in a clinical research setting. In addition, a cold stimulus was used to induce thermogenic gene expression. Adiponectin secretion was measured, and gene expression of 130 genes involved in adipose tissue function was determined. The effect of KDT501 on adipocyte mitochondrial function was analyzed in vitro.

Results: SC WAT explants secreted more total and HMW adiponectin after KDT501 treatment (P < 0.05). After KDT501 treatment, a number of genes involved in thermogenesis and lipolysis were induced by cold (P < 0.05). KDT501 also potentiated β-adrenergic signaling (P < 0.001) and enhanced mitochondrial function in adipocytes (P < 0.001).

Conclusion: KDT501 induced adiponectin secretion posttranscriptionally and increased gene expression of thermogenic and lipolytic genes in response to cold stimulation. These beneficial effects on SC WAT may be explained by the ability of KDT501 to potentiate β-adrenergic signaling and enhance mitochondrial function in adipocytes.

Clinical trial registration: https://www.ClinicalTrials.gov, ID number: NCT02444910.

Keywords: adipocyte secretion; adiponectin; adipose tissue biology; gene expression profiling; metabolic syndrome; mitochondria.

Figures

Figure 1

KDT501 induces total and high-molecular weight (HMW) adiponectin secretion by adipose tissue explants from obese, insulin-resistant subjects. Adipose tissue explants obtained before and after KDT501 treatment were incubated in Dulbecco’s modified Eagles’ medium (DMEM) for 1 h at 37°C. (A) Total and (B) HMW adiponectin concentrations in the DMEM were measured by ELISA and are expressed as the concentration/g adipose/h. (C) Adiponectin gene expression was measured in the corresponding adipose tissue biopsy with the Nanostring nCounter system as described in the Section “Materials and Methods.” Data represent the mean ± SEM (n = 9); data in all panels were analyzed by a paired, two-tailed Student’s t-test (*P < 0.05).

Figure 2

KDT501 treatment alters the subcutaneous white adipose tissue (SC WAT) transcriptional response to cold exposure. The Nanostring nCounter system was used to measure gene expression in SC WAT of subjects treated before and after 1 month KDT501 treatment. A-F) Genes that had a different response to the cold stimulus were identified as described in the Section “Materials and Methods.” Data represent the mean ± SEM (n = 9); data in all panels were analyzed by a paired, two tailed Student’s t-test of the change in gene expression by cold before and after KDT501 treatment (*P < 0.05; **P < 0.01).

Figure 3

Adipocytes treated with KDT501 show a magnified response to norepinephrine and increased fatty acid oxidation rate. (A) Mouse primary brown adipocytes were treated for 16 h with DMSO (vehicle), KDT501 (10 µM), or rosiglitazone (2 µM). Oxygen consumption rate was measured on a Seahorse XFe96 as described in the Section “Materials and Methods.” (B) 3T3-L1 adipocytes were treated for 48 h with KDT501 (10 µM) or rosiglitazone (2 µM), and the rate of basal (endogenous) and maximal (exogenous palmitate added) fatty acid oxidation measured in real time using the XFe96. Data represent four biological replicates. Error bars indicate SD. **P < 0.01; ***P < 0.001 by one-way analysis of variance.

Figure 4

Cold induces total and high-molecular weight (HMW) adiponectin secretion by adipose tissue explants of obese, insulin-resistant subjects. Adipose tissue explants obtained before and after cold treatment (30 min) before and after KDT501 treatment were incubated in Dulbecco’s modified Eagles’ medium (DMEM) for 4-h at 37°C. (A) Total and (B) HMW adiponectin secretion in the DMEM were measured by ELISA and are expressed as the concentration/g adipose/h. (C) Adiponectin gene expression was measured in the corresponding adipose tissue biopsy with the Nanostring nCounter system as described in the Section “Materials and Methods.” (D) Total and (E) HMW adiponectin secretion in the DMEM were measured by ELISA. (F) Adiponectin gene expression was measured in the corresponding adipose tissue biopsy with the Nanostring nCounter system as described in the Section “Materials and Methods.” Data represent the mean ± SEM (n = 9); data in all panels were analyzed by a paired, two tailed Student’s t-test (*P < 0.05; **P < 0.01).

Figure 5

Effect of KDT501 and cold on the expression of genes that regulate adiponectin secretion and multimerization. (A–C) Gene expression was measured by real-time reverse transcriptase polymerase chain reaction as described in the Section “Materials and Methods.” Data represent the mean ± SEM (n = 9); data in all panels were analyzed by a repeated measures analysis of variance (*P < 0.05; **P < 0.01; ***P < 0.001). The data in all panels were also analyzed by a paired, two tailed Student’s t-test of the change in gene expression by cold before and after KDT501 treatment (ERp44: *P < 0.05).