Dr. Kai Sun, MD, PhD

Dr. Kai Sun, MD, PhD

Assistant Professor, Center for Metabolic & Degenerative Diseases

Email Address: Kai.Sun@uth.tmc.edu
Phone Number: 713-500-3190
Room Number: SRB 437A

Narrative

         Dr. Sun received his medical degree from West China University of Medical Sciences, MPH from Peking University, and Ph.D degree from University of California, Riverside. He finished his postdoctoral training in Dr. Philipp Scherer’s laboratory at UT Southwestern Medical Center where he had obtained a remarkable set of observations about adipose tissue remodeling and obesity. He had published the paradigm-shifting findings in high-impact journals such as PNAS, JCI, and Cell Metabolism. In 2015, Dr. Sun was recruited to the Institute of Molecular Medicine (IMM) as a tenure-track Assistant Professor.

         Research interests

         Dr. Sun’s laboratory investigates and discovers novel factors that regulate the dynamics of adipose tissue remodeling during obesity development. The long-term goal of his research is to address the clinical significance of these factors in human obesity, diabetes and cardiovascular diseases.

         In the past years, he has revealed that high fat diet-induced obesity shapes a hypoxic microenvironment that initiates the local fibrosis and inflammation in adipose tissue. The unhealthy adipose tissue eventually leads to systemic insulin resistance and cardiovascular dysregulation. Intriguingly, he found that VEGF-A-induced angiogenesis ameliorates the pathological changes by suppressing the local hypoxia and stimulating sympathetic innervation in both white and brown adipose tissue. His study further reveals that the hypoxia-induced MT1-MMP facilitates the healthy expansion of adipose tissue by stimulating angiogenesis in combination with VEGF-A, thus relieving the pathological conditions. On the other hand, MT1-MMP cleaves collagenous proteins to increase the extracellular matrix (ECM) flexibility in adipose tissue.

        Most recently, Dr. Sun’s laboratory analyzed the dynamics of lipid droplet-associated proteins during adipose tissue remodeling by Mass Spectrometry. He has successfully identified several novel proteins that translocalize onto lipid droplets and the interface of endoplasmic reticulum (ER)-lipid droplets in response to different cellular stimuli. Particularly, he discovered that one of the identified proteins named Carboxyl Esterase 3 (Ces3) targets lipid droplets upon β-adrenergic-stimulation where it exerts the lipolytic function on the lipids. He also discovered that another factor called Dynamin-Related Protein 1 (DRP1) translocates onto ER where it promotes the fission of the nascent lipid droplets from the ER in response to lipid stress. His laboratory continues to apply  state-of-the-art tools and techniques to decipher the mechanisms governing the functions of these novel factors and uncover their potential implication in metabolic health.

Research Projects

  1. Hypoxia stimulated fibrosis and local inflammation in adipose tissue.
  2. Sympathetic innervation in adipose tissue and energy expenditure).
  3. Reversibility of adipose tissue fibrosis by novel anti-fibrotic therapies.
  4. Regulation of the dynamics of lipid droplets and metabolic health.

Recent Publications

Li X, Yang L, Mao Z, Pan X, Zhao Y, Gu X, Eckel-Mahan K, Zuo Z, Tong Q, Hartig SM, Cheng X, Du G, Moore DD, Bellen HJ, Sesaki H, Sun K. Novel role of dynamin-related-protein 1 in dynamics of ER-lipid droplets in adipose tissue.  FASEB J. 2020 Jun; 34(6):8265-8282.  PMCID: PMC7336545

Li X, Zhao Y, Chen C, Yang L, Lee HH, Wang Z, Zhang N, Kolonin MG, An Z, Ge X, Scherer PE, Sun K.  The critical role of MMP14 in adipose tissue remodeling during obesity. Mol Cell Biol. 2020 Mar; 40(8): e00564-19.  PMCID: PMC7108820

Li X, Chan LWC, Li X, Liu C, Yang G, Gao J, Dai M, Wang Y, Xie Z, Liu J, Zhou F, Zheng T, Feng D, Guo S, Li H, Sun K, Yang S. Obesity-Induced Regulator of Calcineurin 1 Overexpression Leads to β-Cell Failure Through Mitophagy Pathway Inhibition. Antioxid Redox Signal. 2020 Mar 1;32(7):413-428.

An YA, Crewe C, Asterholm IW, Sun K, Chen S, Zhang F, Shao M, Funcke JB, Zhang Z, Straub L, Klein S, Kusminski CM, Scherer PE. Dysregulation of Amyloid Precursor Protein Impairs Adipose Tissue Mitochondrial Function and Promotes Obesity. Nat Metab. 2019 Dec;1(12):1243-1257.  PMCID: PMC6980705

Yang L, Li X, Tang H, Gao Z, Zhang K, Sun KA Unique Role of Carboxylesterase 3 (Ces3) in β-Adrenergic Signaling-Stimulated Thermogenesis. Diabetes. 2019 Jun; 68(6):1178-1196.  PMCID: PMC6610024

Li X, Mao Z, Yang L, Sun K. Co-staining Blood Vessels and Nerve Fibers in Adipose Tissue. J Vis Exp. 2019 Feb 13 (144):10.3791/59266.  PMCID: PMC6989151

Zhao Y, Gu X, Zhang N, Kolonin MG, An Z, Sun K. Divergent functions of endotrophin on different cell populations in adipose tissue. Am J Physiol Endocrinol Metab. 2016 Dec 1;311(6):E952-E963.  PMCID: PMC6189636

Li X, Sun K.  Regulation of Lipolysis in Adipose Tissue and Clinical Significance. Adv Exp Med Biol. 2018;1090:199-210.

Sun K, Gao Z, Kolonin MG. Transient inflammatory signaling promotes beige adipogenesis. Sci Signal. 2018 Apr 24;11(527):eaat3192. 

Zhao Y, Li X, Yang L, Eckel-Mahan K, Tong Q, Gu X, Kolonin MG, Sun K. Transient Overexpression of Vascular Endothelial Growth Factor A in Adipose Tissue Promotes Energy Expenditure via Activation of the Sympathetic Nervous System. Mol Cell Biol. 2018 Oct 29;38(22):e00242-18.  PMCID: PMC6206456