Altered morphology and function of the lacrimal functional unit in protein kinase C{alpha} knockout mice.

PURPOSE Protein kinase C (PKC) α plays a major role in the parasympathetic neural stimulation of lacrimal gland (LG) secretion. It also has been reported to have antiapoptotic properties and to promote cell survival. Therefore, the hypothesis for the present study was that PKCα knockout ((-/-)) mice have impaired ocular surface-lacrimal gland signaling, rendering them susceptible to desiccating stress and impaired corneal epithelial wound healing. In this study, the lacrimal function unit (LFU) and the stressed wound-healing response were examined in PKCα(-/-) mice. METHODS In PKCα(+/+) control mice and PKCα(-/-) mice, tear production, osmolarity, and clearance rate were evaluated before and after experimental desiccating stress. Histology and immunofluorescent staining of PKC and epidermal growth factor were performed in tissues of the LFU. Cornified envelope (CE) precursor protein expression and cell proliferation were evaluated. The time course of healing and degree of neutrophil infiltration was evaluated after corneal epithelial wounding. RESULTS Compared with the PKCα(+/+) mice, the PKCα(-/-) mice were noted to have significantly increased lacrimal gland weight, with enlarged, carbohydrate-rich, PAS-positive acinar cells; increased corneal epithelia permeability, with reduced CE expression; and larger conjunctival epithelial goblet cells. The PKCα(-/-) mice showed more rapid corneal epithelial healing, with less neutrophil infiltration and fewer proliferating cells than did the PKCα(+/+) mice. CONCLUSIONS The PKCα(-/-) mice showed lower tear production, which appeared to be caused by impaired secretion by the LG and conjunctival goblet cells. Despite their altered tear dynamics, the PKCα(-/-) mice demonstrated more rapid corneal epithelial wound healing, perhaps due to decreased neutrophil infiltration.

[1]  C. Smith,et al.  Lymphocyte function-associated antigen-1-dependent inhibition of corneal wound healing. , 2006, The American journal of pathology.

[2]  C. Smith,et al.  Platelet response to corneal abrasion is necessary for acute inflammation and efficient re-epithelialization. , 2006, Investigative ophthalmology & visual science.

[3]  S. Yuspa,et al.  CXCR2 ligands and G-CSF mediate PKCα-induced intraepidermal inflammation , 2006 .

[4]  D. Roopenian,et al.  Accelerated wound healing of alkali-burned corneas in MRL mice is associated with a reduced inflammatory signature. , 2005, Investigative ophthalmology & visual science.

[5]  Paul Martin,et al.  Inflammatory cells during wound repair: the good, the bad and the ugly. , 2005, Trends in cell biology.

[6]  Zhuo-Yi Chen,et al.  Effect of Experimental Dry Eye on Tear Sodium Concentration in the Mouse , 2005, Eye & contact lens.

[7]  Rainer Schmidt,et al.  The cornified envelope: a model of cell death in the skin , 2005, Nature Reviews Molecular Cell Biology.

[8]  G. Sharma,et al.  Epidermal and Hepatocyte Growth Factors, but Not Keratinocyte Growth Factor, Modulate Protein Kinase Cα Translocation to the Plasma Membrane through 15(S)-Hydroxyeicosatetraenoic Acid Synthesis* , 2005, Journal of Biological Chemistry.

[9]  C. Vinson,et al.  Activation of Cutaneous Protein Kinase Cα Induces Keratinocyte Apoptosis and Intraepidermal Inflammation by Independent Signaling Pathways , 2003, The Journal of Immunology.

[10]  L. DiPietro,et al.  Accelerated wound closure in neutrophil‐depleted mice , 2003, Journal of leukocyte biology.

[11]  L. Carpenter,et al.  Inhibition of PKCα induces a PKCδ-dependent apoptotic program in salivary epithelial cells , 2003, Cell Death and Differentiation.

[12]  S. Nakashima.  Protein kinase Cα (PKCα): Regulation and biological function , 2002 .

[13]  De-Quan Li,et al.  A mouse model of keratoconjunctivitis sicca. , 2002, Investigative ophthalmology & visual science.

[14]  G. Matthews,et al.  Calcium dependence of exocytosis in lacrimal gland acinar cells. , 2002, American journal of physiology. Cell physiology.

[15]  D. Zoukhri,et al.  Regulation of conjunctival goblet cell secretion by Ca(2+)and protein kinase C. , 2000, Experimental eye research.

[16]  R. Wu,et al.  Induction of cell cornification and enhanced squamous-cell marker SPRR1 gene expression by phorbol ester are regulated by different signaling pathways in human conducting airway epithelial cells. , 2000, American journal of respiratory cell and molecular biology.

[17]  R. Smart,et al.  Overexpression of protein kinase C-alpha in the epidermis of transgenic mice results in striking alterations in phorbol ester-induced inflammation and COX-2, MIP-2 and TNF-alpha expression but not tumor promotion. , 1999, Journal of cell science.

[18]  J. Zieske,et al.  Immunolocalization of muscarinic and VIP receptor subtypes and their role in stimulating goblet cell secretion. , 1999, Investigative ophthalmology & visual science.

[19]  W. Feuer,et al.  Correlation of tear fluorescein clearance and Schirmer test scores with ocular irritation symptoms. , 1999, Ophthalmology.

[20]  A. Fields,et al.  Interleukin-1-induced Nuclear Factor-κB-IκBα Autoregulatory Feedback Loop in Hepatocytes , 1999, The Journal of Biological Chemistry.

[21]  R. Beuerman,et al.  The pathology of dry eye: the interaction between the ocular surface and lacrimal glands. , 1998, Cornea.

[22]  H. Bazan,et al.  Selective changes in protein kinase C (PKC) isoform expression in rabbit corneal epithelium during wound healing. Inhibition of corneal epithelial repair by PKCalpha antisense. , 1998, Experimental eye research.

[23]  W. May,et al.  A Functional Role for Mitochondrial Protein Kinase Cα in Bcl2 Phosphorylation and Suppression of Apoptosis* , 1998, The Journal of Biological Chemistry.

[24]  N. Huh,et al.  Induction of Differentiation in Normal Human Keratinocytes by Adenovirus-Mediated Introduction of the η and δ Isoforms of Protein Kinase C , 1998, Molecular and Cellular Biology.

[25]  D. Zoukhri,et al.  Immunolocalization of Lacrimal Gland PKC Isoforms. Effect of Phorbol Esters and Cholinergic Agonists on Their Cellular Distribution , 1997, The Journal of Membrane Biology.

[26]  D. Dartt,et al.  Vasoactive intestinal peptide-stimulated glycoconjugate secretion from conjunctival goblet cells. , 1996, Experimental eye research.

[27]  D. Zoukhri,et al.  Role of protein kinase C in cholinergic stimulation of lacrimal gland protein secretion , 1994, FEBS letters.

[28]  H. Bazan,et al.  Protein kinase C subspecies in rabbit corneai epithelium: increased activity of $aL subspecies during wound healing , 1992 .

[29]  Y. Nishizuka,et al.  The molecular heterogeneity of protein kinase C and its implications for cellular regulation , 1988, Nature.

[30]  S. Yuspa,et al.  CXCR2 ligands and G-CSF mediate PKCalpha-induced intraepidermal inflammation. , 2006, The Journal of clinical investigation.

[31]  L. Carpenter,et al.  Inhibition of PKCalpha induces a PKCdelta-dependent apoptotic program in salivary epithelial cells. , 2003, Cell death and differentiation.

[32]  M. Sajan,et al.  Knockout of PKC alpha enhances insulin signaling through PI3K. , 2002, Molecular endocrinology.

[33]  S. Nakashima.  Protein kinase C alpha (PKC alpha): regulation and biological function. , 2002, Journal of biochemistry.

[34]  M. Sajan,et al.  Knockout of PKC Enhances Insulin Signaling Through PI3K , 2002 .

[35]  A. Brasier,et al.  Interleukin-1-induced nuclear factor-kappaB-IkappaBalpha autoregulatory feedback loop in hepatocytes. A role for protein kinase calpha in post-transcriptional regulation of ikappabalpha resynthesis. , 1999, The Journal of biological chemistry.

[36]  C. Sergheraert,et al.  Protein kinase C isoforms differentially control lacrimal gland functions. , 1998, Advances in experimental medicine and biology.

[37]  A. Toker,et al.  Lacrimal gland PKC isoforms are differentially involved in agonist-induced protein secretion. , 1997, The American journal of physiology.

[38]  H. Bazan,et al.  Protein kinase C substrates in corneal epithelium during wound healing: the phosphorylation of growth associated protein-43 (GAP-43). , 1995, Experimental eye research.

[39]  D. Dartt.  Regulation of tear secretion. , 1994, Advances in experimental medicine and biology.

[40]  H. Bazan,et al.  Protein kinase C subspecies in rabbit corneal epithelium: increased activity of alpha subspecies during wound healing. , 1992, Current eye research.

[41]  Transforming Growth Factor- (cid:1) 1 Regulation of Collagenase-3 Expression in Osteoblastic Cells by Cross-talk between the Smad and MAPK Signaling Pathways and Their Components, Smad2 and Runx2* , 2022 .