Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model

role of endosomes/Lysosomes

Shankar C. Sanka, David C. Bennett, Jose Rojas, Geraldine B. Tasby, Cynthia J. Meininger, Guoyao Wu, Donald E. Wesson, Curt Pfarr, Raul Martinez-Zaguilan

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)

Abstract

Cytosolic Ca 2+ ([Ca 2+] cyt) regulates several functions, e.g. cell growth, contraction, secretion, etc. In many cell types, ion homeostasis appears to be coupled with glucose metabolism. In certain cell types, a strict coupling between glycolysis and the activity of Sarcoplasmic/Endoplasmic Reticulum Ca 2+-ATPases (SERCA) has been suggested. Glucose metabolism is altered in diabetes. We hypothesize that: (a) Ca 2+ homeostasis is altered in microvascular endothelial cells from diabetic animals due to the dysfunction of glycolysis coupling the activity of SERCA; (b) endosomal/lysosomal (E/L) compartments expressing SERCA are involved in the dysfunction associated with diabetes. Ca 2+ ions in E/L compartments can be studied by either spectral imaging/confocal microscopy in single cells, or by fluorescence spectroscopy in cell populations. In cell populations, agonist stimulation elicited greater [Ca 2+] cyt increases in cells from diabetic than from normal animals. Simultaneous measurements of [Ca 2+] cyt and Ca 2+ in E/L compartments ([Ca 2+] E/L) using fluorescence spectroscopy and spectral imaging/confocal microscopy, demonstrate that Ca 2+ is released from E/L compartments following agonist stimulation. Immunocytochemical studies demonstrate that E/L compartments exhibit the machinery to regulate Ca 2+: SERCA and ryanodine receptor (RyR) coupled Ca 2+ channels. Our functional studies, using confocal/spectral imaging microscopy, indicated that E/L compartments employ SERCA and RyR coupled Ca 2+ channels to refill and release Ca 2+, respectively. Glucose modulates refilling of E/L compartments with Ca 2+ via SERCA, since SERCA inhibitors suppress this refilling. The regulation of these phenomena are altered in diabetes. These data indicate that E/L compartments are important for Ca 2+ homeostasis.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSPIE
Pages56-66
Number of pages11
Volume3924
StatePublished - 2000
Externally publishedYes
EventMolecular Imaging: Reporters, Dyes, Markers, and Instrumentation - San Jose, CA, USA
Duration: Jan 23 2000Jan 24 2000

Other

OtherMolecular Imaging: Reporters, Dyes, Markers, and Instrumentation
CitySan Jose, CA, USA
Period1/23/001/24/00

Fingerprint

lysosomes
homeostasis
insulin
endoplasmic reticulum
Insulin
Endothelial cells
compartments
Medical problems
Glucose
glycolysis
glucose
refilling
Confocal microscopy
Fluorescence spectroscopy
Imaging techniques
Metabolism
metabolism
microscopy
cells
stimulation

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Sanka, S. C., Bennett, D. C., Rojas, J., Tasby, G. B., Meininger, C. J., Wu, G., ... Martinez-Zaguilan, R. (2000). Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model: role of endosomes/Lysosomes. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 3924, pp. 56-66). SPIE.

Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model : role of endosomes/Lysosomes. / Sanka, Shankar C.; Bennett, David C.; Rojas, Jose; Tasby, Geraldine B.; Meininger, Cynthia J.; Wu, Guoyao; Wesson, Donald E.; Pfarr, Curt; Martinez-Zaguilan, Raul.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3924 SPIE, 2000. p. 56-66.

Research output: Chapter in Book/Report/Conference proceedingChapter

Sanka, SC, Bennett, DC, Rojas, J, Tasby, GB, Meininger, CJ, Wu, G, Wesson, DE, Pfarr, C & Martinez-Zaguilan, R 2000, Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model: role of endosomes/Lysosomes. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 3924, SPIE, pp. 56-66, Molecular Imaging: Reporters, Dyes, Markers, and Instrumentation, San Jose, CA, USA, 1/23/00.
Sanka SC, Bennett DC, Rojas J, Tasby GB, Meininger CJ, Wu G et al. Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model: role of endosomes/Lysosomes. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3924. SPIE. 2000. p. 56-66
Sanka, Shankar C. ; Bennett, David C. ; Rojas, Jose ; Tasby, Geraldine B. ; Meininger, Cynthia J. ; Wu, Guoyao ; Wesson, Donald E. ; Pfarr, Curt ; Martinez-Zaguilan, Raul. / Ca 2+ homeostasis in microvascular endothelial cells from an insulin dependent diabetic model : role of endosomes/Lysosomes. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3924 SPIE, 2000. pp. 56-66
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AU - Tasby, Geraldine B.

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AU - Wesson, Donald E.

AU - Pfarr, Curt

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