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The Effect and Mechanism of Gene Fam20a on the Development and Function of Salivary Glands in Mice. Arch Oral Biol 2022; 137:105367. [DOI: 10.1016/j.archoralbio.2022.105367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 11/21/2022]
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Scheving LA, Zhang X, Stevenson MC, Threadgill DW, Russell WE. Loss of hepatocyte EGFR has no effect alone but exacerbates carbon tetrachloride-induced liver injury and impairs regeneration in hepatocyte Met-deficient mice. Am J Physiol Gastrointest Liver Physiol 2015; 308:G364-77. [PMID: 25414100 PMCID: PMC4346751 DOI: 10.1152/ajpgi.00364.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role(s) of the epidermal growth factor receptor (EGFR) in hepatocytes is unknown. We generated a murine hepatocyte specific-EGFR knockout (KO) model to evaluate how loss of hepatocellular EGFR expression affects processes such as EGF clearance, circulating EGF concentrations, and liver regeneration following 70% resection or CCl4-induced centrilobular injury. We were able to disrupt EGFR expression effectively in hepatocytes and showed that the ability of EGF and heregulin (HRG) to phosphorylate EGFR and ERBB3, respectively, required EGFR. Loss of hepatocellular EGFR impaired clearance of exogenous EGF from the portal circulation but paradoxically resulted in reduced circulating levels of endogenous EGF. This was associated with decreased submandibular salivary gland production of EGF. EGFR disruption did not result in increased expression of other ERBB proteins or Met, except in neonatal mice. Liver regeneration following 70% hepatectomy revealed a mild phenotype, with no change in cyclin D1 expression and slight differences in cyclin A expression compared with controls. Peak 5-bromo-2'-deoxyuridine labeling was shifted from 36 to 48 h. Centrilobular damage and regenerative response induced by carbon tetrachloride (CCl4) were identical in the KO and wild-type mice. In contrast, loss of Met increased CCl4-induced necrosis and delayed regeneration. Although loss of hepatocellular EGFR alone did not have an effect in this model, EGFR-Met double KOs displayed enhanced necrosis and delayed liver regeneration compared with Met KOs alone. This suggests that EGFR and Met may partially compensate for the loss of the other, although other compensatory mechanisms can be envisioned.
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Affiliation(s)
- Lawrence A. Scheving
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee; ,3Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - Xiuqi Zhang
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - Mary C. Stevenson
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - David W. Threadgill
- 6Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas; and ,7Department of Molecular and Cellular Medicine, Texas A&M University, College Station, Texas
| | - William E. Russell
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee; ,2Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee; ,3Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee; ,4Vanderbilt Diabetes Center, Vanderbilt University Medical Center, Nashville, Tennessee; ,5Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee;
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Cangussu SD, Vieira FG, Rossoni RB. Sexual dimorphism and seasonal variation in submandibular gland histology of Bolomys lasiurus (Rodentia, Muridae). J Morphol 2002; 254:320-7. [PMID: 12386901 DOI: 10.1002/jmor.10041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Wild rodents (Bolomys lasiurus) of both sexes were caught in a cerrado grassland area during the dry (July-September) and rainy (January-March) seasons of Brazil. Fasted animals were perfused with Karnovsky fixative through the left ventricle, under ether anesthesia, and the submandibular gland was processed for embedding in historesin. Histological and histometric data show sexual dimorphism at both seasons. In the volume percentage of the granular convoluted tubules (GCT) and their secretory granules, the males exhibited higher values. The absolute volume occupied by these structures, however, was dimorphic only in the rainy season. The diameter of the GCT, the height of its epithelium, and its total length were also greater in males during the rainy season. The absolute volumes of the acini and of the ductal tree were identical in both sexes in the dry and rainy seasons but the acinar diameter increased in the males and females during the rainy season. The sexual dimorphism and the seasonal variations now described in the B. lasiurus submandibular glands could be explained by the augmented reproductive activity of the males in the rainy period.
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Affiliation(s)
- S D Cangussu
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, 30161-970 Belo Horizonte MG, Brazil
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