Physiology and Biophysics Discipline

Center for Cancer Cell Biology, Immunology, and Infection

Dr. White received his PhD in Physiology from the Queen’s University Belfast in the United Kingdom. His graduate work focused on calcium signaling and the use of electrophysiology and microscopy as tools to study cytoplasmic and organelle calcium fluxes in smooth muscle cells.

As a postdoctoral fellow at the University of Pennsylvania, he helped develop cell models and technical approaches for the study of the InsP₃ receptor intracellular calcium release channels in their native membranes.

On joining the Chicago Medical School faculty in the Physiology & Biophysics discipline, Dr. White established an active research program that has addressed important questions relating to calcium signaling dysfunction in cancer, metabolic disease, and diabetes.

CURRENT RESEARCH PROJECTS

Our current research efforts are focused on understanding how chronic inflammation caused by obesity impinges on the microvascular system.

Microvascular disease is one of the first clinical manifestations of obesity and is a serious health issue because it directly contributes to the development of hypertension, insulin resistance, and type-2 diabetes. Our goal is to define the mechanisms that catalyze the initiation and drive the progression of microvascular disease. We are currently testing the hypothesis that activation of the innate immune system plays a central role in the development of microvascular dysfunction in obesity. 

Early microvascular disease is characterized by increased vessel contractility caused by changes in the way vessels respond to vasoconstrictor and vasodilator inputs. Contractility is tightly regulated by the physiology of the perivascular adipose tissue (PVAT), the layer of fat that surrounds most vessels and is composed of adipocytes, fibroblasts, and immune cells. Macrophages that adopt a proinflammatory phenotype are recruited to adipose tissue during obesity. We discovered that proinflammatory macrophages localized within the PVAT contribute to vascular dysfunction in obesity. We are currently studying how PVAT-macrophages communicate with the underlying vessels. 

We are also interested in how obesity modifies macrophage signal transduction. We discovered that the macrophage store-operated calcium entry pathway is physiologically regulated by the gaseous signaling molecular hydrogen sulfide. We are currently studying how this signaling loop plays a role in driving macrophage inflammatory signaling and recruitment to the PVAT during obesity.

Publications

Full Text: 

Peterson, D.R., et al.,  A Glutathione Precursor Reduces Oxidative Injury to Cultured Embryonic Cardiomyocytes. American Journal of Therapeutics. 2018

White, C., The Regulation of Tumor Cell Invasion and Metastasis by Endoplasmic Reticulum-to-Mitochondrial Ca²⁺ Transfer. Frontiers in Oncology, 2017. 7: p. 171.

Candela, J., R. Wang, and C. White, Microvascular Endothelial Dysfunction in Obesity Is Driven by Macrophage-Dependent Hydrogen Sulfide Depletion. Arterioscler Thromb Vasc Biol, 2017. 37(5): p. 889-899.

Wang, J., et al., Role of cystathionine-gamma-lyase in hypoxia-induced changes in TASK activity, intracellular [Ca²⁺] and ventilation in mice. Respir Physiol Neurobiol, 2017. 246: p. 98-106.

Zhao, G., et al., N-(3-oxo-acyl) homoserine lactone inhibits tumor growth independent of Bcl-2 proteins. Oncotarget, 2016. 7(5): p. 5924-42.

Demczuk, M., et al., Retinoic Acid Regulates Calcium Signaling to Promote Mouse Ovarian Granulosa Cell Proliferation. Biol Reprod, 2016. 95(3): p. 70.

Candela, J., G.V. Velmurugan, and C. White, Hydrogen sulfide depletion contributes to microvascular remodeling in obesity. Am J Physiol Heart Circ Physiol, 2016. 310(9): p. H1071-80.

White, C., A. Nixon, and N.A. Bradbury, Determining Membrane Protein Topology Using Fluorescence Protease Protection (FPP). J Vis Exp, 2015(98).

Velmurugan, G.V., et al., Depletion of H₂S during obesity enhances store-operated Ca2+ entry in adipose tissue macrophages to increase cytokine production. Science Signaling, 2015. 8(407): p. ra128.

Rajan, S., et al., Structural transition in Bcl-xL and its potential association with mitochondrial calcium ion transport. Scientific Reports, 2015. 5: p. 10609.

Kim, D., et al., Hydrogen sulfide and hypoxia-induced changes in TASK (K2P3/9) activity and intracellular Ca²⁺ concentration in rat carotid body glomus cells. Respir Physiol Neurobiol, 2015. 215: p. 30-8.

Kang, D., et al., Increase in cytosolic Ca²⁺ produced by hypoxia and other depolarizing stimuli activates a non-selective cation channel in chemoreceptor cells of rat carotid body. J Physiol, 2014. 592(9): p. 1975-92.

Huang, H., et al., Mcl-1 promotes lung cancer cell migration by directly interacting with VDAC to increase mitochondrial Ca²⁺ uptake and reactive oxygen species generation. Cell Death Dis, 2014. 5: p. e1482.

Velmurugan, G.V., et al., Defective Nrf2-dependent redox signalling contributes to microvascular dysfunction in type 2 diabetes. Cardiovasc Res, 2013. 100(1): p. 143-50.

Nixon, A., et al., Determination of the membrane topology of lemur tyrosine kinase 2 (LMTK2) by fluorescence protease protection. Am J Physiol Cell Physiol, 2013. 304(2): p. C164-9.

Huang, H., et al., An interaction between Bcl-xL and the voltage-dependent anion channel (VDAC) promotes mitochondrial Ca²⁺ uptake. J Biol Chem, 2013. 288(27): p. 19870-81.

Velmurugan, G.V. and C. White, Calcium homeostasis in vascular smooth muscle cells is altered in type 2 diabetes by Bcl-2 protein modulation of InsP­₃R calcium release channels. Am J Physiol Heart Circ Physiol, 2012. 302(1): p. H124-34.

Eno, C.O., et al., Distinct roles of mitochondria- and ER-localized Bcl-xL in apoptosis resistance and Ca²⁺ homeostasis. Mol Biol Cell, 2012. 23(13): p. 2605-18.

Wang, X., et al., Bcl-2 proteins regulate ER membrane permeability to luminal proteins during ER stress-induced apoptosis. Cell Death Differ, 2011. 18(1): p. 38-47.

Bozym, R.A., et al., Calcium signals and calpain-dependent necrosis are essential for release of coxsackievirus B from polarized intestinal epithelial cells. Mol Biol Cell, 2011. 22(17): p. 3010-21.

George Paul, A., et al., Piracy of prostaglandin E2/EP receptor-mediated signaling by Kaposi's sarcoma-associated herpes virus (HHV-8) for latency gene expression: strategy of a successful pathogen. Cancer Res, 2010. 70(9): p. 3697-708.

Eckenrode, E.F., et al., Apoptosis protection by Mcl-1 and Bcl-2 modulation of inositol 1,4,5-trisphosphate receptor-dependent Ca2+ signaling. J Biol Chem, 2010. 285(18): p. 13678-84.

Li, C., et al., Apoptosis regulation by Bcl-x(L) modulation of mammalian inositol 1,4,5-trisphosphate receptor channel isoform gating. Proc Natl Acad Sci U S A, 2007. 104(30): p. 12565-70.

Jones, R.G., et al., The proapoptotic factors Bax and Bak regulate T Cell proliferation through control of endoplasmic reticulum Ca²⁺ homeostasis. Immunity, 2007. 27(2): p. 268-80.

Ionescu, L., et al., Mode switching is the major mechanism of ligand regulation of InsP3 receptor calcium release channels. J Gen Physiol, 2007. 130(6): p. 631-45.

Foskett, J.K., et al., Inositol trisphosphate receptor Ca²⁺ release channels. Physiol Rev, 2007. 87(2): p. 593-658.

White, C., et al., CIB1, a ubiquitously expressed Ca²⁺-binding protein ligand of the InsP₃ receptor Ca²⁺ release channel. J Biol Chem, 2006. 281(30): p. 20825-33.

Mak, D.D., et al., Nuclear Patch Clamp Electrophysiology of Inositol Trisphosphate Receptor Ca²⁺ Release Channels. 2nd ed. Methods in signal transduction. 2006, Boca Raton: CRC/Taylor & Francis. p. 509.

Ionescu, L., et al., Graded recruitment and inactivation of single InsP₃ receptor Ca²⁺-release channels: implications for quantal Ca²⁺release. J Physiol, 2006. 573(Pt 3): p. 645-62.

White, C., et al., The endoplasmic reticulum gateway to apoptosis by Bcl-X(L) modulation of the InsP₃R. Nat Cell Biol, 2005. 7(10): p. 1021-8.

Kumar, D., et al., Electrophysiological and pharmacological characterization of K+-currents in muscle fibres isolated from the ventral sucker of Fasciola hepatica. Parasitology, 2004. 129(Pt 6): p. 779-93.

White, C. and J.G. McGeown, Inositol 1,4,5-trisphosphate receptors modulate Ca²⁺ sparks and Ca²⁺ store content in vas deferens myocytes. Am J Physiol Cell Physiol, 2003. 285(1): p. C195-204.

White, C. and J.G. McGeown, Carbachol triggers RyR-dependent Ca²⁺ release via activation of IP₃ receptors in isolated rat gastric myocytes. J Physiol, 2002. 542(Pt 3): p. 725-33.

White, C. and G. McGeown, Imaging of changes in sarcoplasmic reticulum [Ca²⁺] using Oregon Green BAPTA 5N and confocal laser scanning microscopy. Cell Calcium, 2002. 31(4): p. 151-9.

White, C. and J.G. McGeown, Ca²⁺ uptake by the sarcoplasmic reticulum decreases the amplitude of depolarization-dependent [Ca²⁺]i transients in rat gastric myocytes. Pflugers Arch, 2000. 440(3): p. 488-95.

White, C. and J.G. McGeown, Regulation of basal intracellular calcium concentration by the sarcoplasmic reticulum in myocytes from the rat gastric antrum. J Physiol, 2000. 529 Pt 2: p. 395-404.