Depolymerization of hepatocellular microtubules after partial hepatectomy

Vasudeva R. Bommineni, Namita Roy Chowdhury, George Y. Wu, Catherine H. Wu, Nicholas Franki, Richard M. Hays, Jayanta Roy-Chowdhury

Research output: Contribution to journalArticle

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Abstract

Asialoglycoproteins (ASG) are internalized by hepatocytes by ASG receptor (ASGR)-mediated endocytosis. We have shown previously that when a plasmid DNA, pAlb(9-12)CAT (expressing chloramphenicol acetyltransferase driven by an albumin promoter enhancer), was complexed with an ASG-polylysine conjugate and injected intravenously in rats, 80% of the DNA was internalized by the liver. In normal recipient rats, over 95% of the internalized DNA was degraded in 4 h; the plasmid was undetectable after 48 h. In contrast, when 66% hepatectomy was performed 20 min after DNA administration, the internalized DNA persisted for several weeks in cytoplasmic vesicles (Chowdhury, N. R., Wu, C. H., Wu, B. Y., Yerneni, P. C., Bommineni, V. R., and Chowdhury, J. R. (1993) J. Biol. Chem. 268, 11265-11271). Since microtubules are required for the translocation of ligand-containing endosomes to lysosomes, the site of ligand degradation, we hypothesized that persistence of the endocytosed DNA might be related to changes in microtubular structure and function. To test this hypothesis, we examined hepatocellular microtubules by immunofluorescence confocal microscopy. Liver from untreated rats or sham-operated controls showed a network of fibrillar microtubules throughout the cytoplasm. The extent of the microtubular network was substantially reduced 3-6 h after 66% hepatectomy. By 24 h, microtubules had regenerated. Intraportal infusion of cycloheximide (250 mg/kg body weight) 15 min before 66% hepatectomy, prevented microtubular disruption, indicating that protein synthesis is required for this process. Immunotransblot analysis showed that hepatic α-tubulin concentration remained unchanged through microtubular disassembly and subsequent reassembly, which is consistent with conservation and reutilization of tubulin released by depolymerization of microtubules.

Original languageEnglish (US)
Pages (from-to)25200-25205
Number of pages6
JournalJournal of Biological Chemistry
Volume269
Issue number40
StatePublished - Oct 7 1994

Fingerprint

Depolymerization
Hepatectomy
Microtubules
DNA
Rats
Tubulin
Endocytosis
Liver
Plasmids
Asialoglycoproteins
Asialoglycoprotein Receptor
Cytoplasmic Vesicles
Ligands
Chloramphenicol O-Acetyltransferase
Confocal microscopy
Endosomes
Cycloheximide
Lysosomes
Fluorescence Microscopy
Confocal Microscopy

ASJC Scopus subject areas

  • Biochemistry

Cite this

Bommineni, V. R., Chowdhury, N. R., Wu, G. Y., Wu, C. H., Franki, N., Hays, R. M., & Roy-Chowdhury, J. (1994). Depolymerization of hepatocellular microtubules after partial hepatectomy. Journal of Biological Chemistry, 269(40), 25200-25205.

Depolymerization of hepatocellular microtubules after partial hepatectomy. / Bommineni, Vasudeva R.; Chowdhury, Namita Roy; Wu, George Y.; Wu, Catherine H.; Franki, Nicholas; Hays, Richard M.; Roy-Chowdhury, Jayanta.

In: Journal of Biological Chemistry, Vol. 269, No. 40, 07.10.1994, p. 25200-25205.

Research output: Contribution to journalArticle

Bommineni, VR, Chowdhury, NR, Wu, GY, Wu, CH, Franki, N, Hays, RM & Roy-Chowdhury, J 1994, 'Depolymerization of hepatocellular microtubules after partial hepatectomy', Journal of Biological Chemistry, vol. 269, no. 40, pp. 25200-25205.
Bommineni VR, Chowdhury NR, Wu GY, Wu CH, Franki N, Hays RM et al. Depolymerization of hepatocellular microtubules after partial hepatectomy. Journal of Biological Chemistry. 1994 Oct 7;269(40):25200-25205.
Bommineni, Vasudeva R. ; Chowdhury, Namita Roy ; Wu, George Y. ; Wu, Catherine H. ; Franki, Nicholas ; Hays, Richard M. ; Roy-Chowdhury, Jayanta. / Depolymerization of hepatocellular microtubules after partial hepatectomy. In: Journal of Biological Chemistry. 1994 ; Vol. 269, No. 40. pp. 25200-25205.
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abstract = "Asialoglycoproteins (ASG) are internalized by hepatocytes by ASG receptor (ASGR)-mediated endocytosis. We have shown previously that when a plasmid DNA, pAlb(9-12)CAT (expressing chloramphenicol acetyltransferase driven by an albumin promoter enhancer), was complexed with an ASG-polylysine conjugate and injected intravenously in rats, 80{\%} of the DNA was internalized by the liver. In normal recipient rats, over 95{\%} of the internalized DNA was degraded in 4 h; the plasmid was undetectable after 48 h. In contrast, when 66{\%} hepatectomy was performed 20 min after DNA administration, the internalized DNA persisted for several weeks in cytoplasmic vesicles (Chowdhury, N. R., Wu, C. H., Wu, B. Y., Yerneni, P. C., Bommineni, V. R., and Chowdhury, J. R. (1993) J. Biol. Chem. 268, 11265-11271). Since microtubules are required for the translocation of ligand-containing endosomes to lysosomes, the site of ligand degradation, we hypothesized that persistence of the endocytosed DNA might be related to changes in microtubular structure and function. To test this hypothesis, we examined hepatocellular microtubules by immunofluorescence confocal microscopy. Liver from untreated rats or sham-operated controls showed a network of fibrillar microtubules throughout the cytoplasm. The extent of the microtubular network was substantially reduced 3-6 h after 66{\%} hepatectomy. By 24 h, microtubules had regenerated. Intraportal infusion of cycloheximide (250 mg/kg body weight) 15 min before 66{\%} hepatectomy, prevented microtubular disruption, indicating that protein synthesis is required for this process. Immunotransblot analysis showed that hepatic α-tubulin concentration remained unchanged through microtubular disassembly and subsequent reassembly, which is consistent with conservation and reutilization of tubulin released by depolymerization of microtubules.",
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