NKG2D Ligand Expression Induced by Oxidative Stress Mitigates Cutaneous Ischemia-Reperfusion Injury.

Pressure ulcers represent a crucial clinical problem, especially in hospitalized patients. Ischemia-reperfusion (I-R) is an important cause of these lesions. Natural killer (NK), invariant NK T (iNKT), and dendritic epidermal T-cells, which express the natural killer group 2, member D (NKG2D) receptor, have been reported to have physiological roles in skin tissue repair and wound healing. However, a role for NKG2D-NKG2D ligand interactions in I-R-induced skin injury has not been determined. Using a murine pressure ulcer model, we demonstrated that I-R-induced ulcers in NKG2D-deficient mice were larger than those in wild-type or T-cell receptor δ knockout mice. Histopathological evaluation revealed that accumulation of macrophages and neutrophils at the peripheral deep dermis and subcutaneous tissue of the ulcers was enhanced in NKG2D-deficient mice. Rae-1 mRNA, which encodes an NKG2D ligand, was induced, and RAE-1 protein was detected immunohistochemically in fibroblasts and inflammatory cells in the dermis after reperfusion. RAE-1 expression was also increased in primary mouse fibroblasts treated with sodium arsenite. These results suggested that NKG2D ligand expression was induced by oxidative stress after I-R injury and support a putative role for this ligand in wound repair. Furthermore, the influx of NKG2D-positive cells at I-R sites may mitigate pressure ulcers via NKG2D-NKG2D ligand interactions.

P450 Side-Chain Cleavage Enzyme (P450-SCC) Is an Ovarian Autoantigen in a Mouse Model for Autoimmune Oophoritis.

Steroid-producing cells contain key cytochrome P450 enzymes, such as side-chain cleavage (P450-SCC) and 17α-hydroxylase (17α-OH). They are required for steroid hormone synthesis and considered antigens associated with Addison's disease and autoimmune primary ovarian insufficiency (POI). We studied an animal model for human autoimmune POI in mice with autoimmune oophoritis induced by neonatal thymectomy performed at day 3 (TX3). We previously identified an oocyte-specific protein as a major antigen inciting autoimmune oophoritis in mice. In this study, we characterized ovarian steroid-producing cell antigens. Using indirect immunofluorescence staining, we tested immune reactions in mouse ovarian and adrenal tissue sections with sera from TX3 female mice. More than half of the TX3 mice (8 of 15) produced antibodies reacting with both ovarian and adrenal steroid-producing cells, including some that reacted to oocytes as well. We produced recombinant proteins for the three key steroidogenic enzymes 17α-OH, P450-SSC, and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and tested their immune reactions with individual mouse sera. By immunoblotting, all mouse sera that reacted with the steroid-producing cells (n = 8) were shown to react with the P450-SCC, but not with the 17α-OH or 3ß-HSD recombinant proteins. The sham-operated mouse sera and TX3 mouse sera negative for steroid-producing cells did not react with the P450-SCC recombinant protein. Our findings indicate that the P450-SCC is a specific and unique major antigen within the ovarian steroid-producing cells. Given their similarity of predicted antigenicity, we assume that P450-SCC acts in human autoimmune POI as it does in mouse autoimmune oophoritis.

Case Report: Hereditary Fibrosing Poikiloderma With Tendon Contractures, Myopathy, and Pulmonary Fibrosis (POIKTMP) Presenting With Liver Cirrhosis and Steroid-Responsive Interstitial Pneumonia.

Background: Hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis (POIKTMP) is an extremely rare disease caused by mutations in FAM111B, and only approximately 30 cases have been reported worldwide. Some patients develop interstitial pneumonia, which may lead to progressive pulmonary fibrosis and poor prognosis. However, no effective treatment for interstitial pneumonia associated with POIKTMP has been reported. Here, we report an autopsy case of POIKTMP, wherein interstitial pneumonia was improved by corticosteroids. Case Presentation: A 44-year-old Japanese man was referred to our hospital due to poikiloderma, hypotrichosis, and interstitial pneumonia. He developed progressive poikiloderma and muscle weakness since infancy. He also had tendon contractures, short stature, liver cirrhosis, and interstitial pneumonia. Mutation analysis of FAM111B revealed a novel and de novo heterozygous missense mutation, c.1886T > G (p(Phe629Cys)), through which we were able to diagnose the patient with POIKTMP. 3 years after the POIKTMP diagnosis, interstitial pneumonia had worsened. After 2 weeks of administrating 40 mg/day of prednisolone, his symptoms and lung shadows improved. However, he subsequently developed severe hepatic encephalopathy and eventually died of respiratory failure due to bacterial pneumonia and pulmonary edema. Autopsy revealed an unclassifiable pattern of interstitial pneumonia, as well as the presence of fibrosis and fatty degeneration in several organs, including the liver, kidney, skeletal muscle, heart, pancreas, and thyroid. Conclusions: We report a case of POIKTMP in which interstitial pneumonia was improved by corticosteroids, suggesting that corticosteroids could be an option for the treatment of interstitial pneumonia associated with this disease.

Expression of cathepsins B, D and K in thymic epithelial tumours.

AIM: Cathepsins are proteases that regulate a wide range of physiological processes, including protein turnover, cell signalling and antigen presentation. Recent studies have shown that cathepsins are highly upregulated in many types of tumours. Of the 15 cathepsins in humans, cathepsins V and S are abundantly expressed in the thymus, and we previously showed that the immunostaining of these cathepsins could serve as diagnostic markers for thymic epithelial tumours. However, little is known about the expression of other cathepsins in thymic epithelial tumours. To determine the diagnostic implications of cathepsins, we performed immunohistochemical analysis of cathepsin B (CTB), cathepsin D (CTD) and cathepsin K (CTK), all of which have been reported to correlate with the progression of squamous cell carcinoma. METHODS: The association between cathepsin expression and clinicopathological features was evaluated in 122 cases of thymoma and thymic carcinoma. RESULTS: CTB and CTD were frequently expressed in type A and type AB thymomas. In contrast, CTB and CTD were significantly less common in type B thymomas than in type A or AB thymomas. In type AB thymomas, the expression of CTB correlated with histological features, and was found predominantly in the type A component. Notably, CTK was expressed most commonly in thymic carcinomas, and patients who died of the disease showed increased expression of CTK. CONCLUSIONS: The expression of CTB and CTD correlated with the histological subtype of thymoma. In addition, the expression of CTK appears to be useful for the diagnosis of thymic carcinomas and as a prognostic marker.

Expression of the immunoproteasome subunit ß5i in non-small cell lung carcinomas.

AIM: The immunoproteasome is a specific proteasome isoform whose proteolytic activity enhances the generation of antigenic peptides to be presented by major histocompatibility complex class I molecules to CD8+ T cells. Physiologically, it is expressed abundantly in immune cells and is induced in somatic cells by cytokines, especially interferon-γ. Recently, variable expression of immunoproteasomes has been demonstrated in different types of cancers. However, the clinical significance of immunoproteasome expression in malignant tumours is poorly understood. In this study, we performed clinicopathological evaluation of immunoproteasome subunit ß5i in non-small cell lung carcinomas (NSCLCs). METHODS: Tumour tissues were collected from 155 patients with NSCLCs, and immunohistochemical analysis for ß5i was performed in relation to the prognosis of patients. RESULTS: High expression of ß5i was found in about 20% of all NSCLCs and was found significantly more frequently (40%) in the adenocarcinoma subset. High expression of ß5i was associated with a better 5-year relative survival rate in patients with pStage I to II adenocarcinoma and was also a significant and independent favourable prognostic factor in adenocarcinoma patients. In addition, when we performed in vitro analysis using NSCLC cell lines, combined treatment with the immunoproteasome-specific inhibitor ONX0914 and the proteasome inhibitor MG132 enhanced cell death in ß5i-expressing NSCLC cell lines. CONCLUSION: The expression of immunoproteasome can be explored as both a prognostic factor and a potential therapeutic target in NSCLCs. Since immunoproteasomes have crucial role in the antigen presentation, further studies may help to provide essential knowledge for therapeutic strategies in anticancer immunotherapy.

Pulmonary capillary hemangiomatosis-predominant vasculopathy in a patient with rheumatoid arthritis-associated interstitial lung disease: An autopsy report.

Pulmonary capillary hemangiomatosis (PCH) is a rare cause of pulmonary hypertension (PH) associated with poor prognosis. Clinically, it is characterized by severe hypoxemia, centrilobular ground-glass opacities on computed tomography, and pulmonary congestion triggered by pulmonary vasodilating therapy. In some cases, PCH has been reported to develop with other disorders including connective tissue disease; however, to date, no reports have described PCH in a patient with rheumatoid arthritis. We report a case of a 59-year-old male PCH patient with rheumatoid arthritis and associated pulmonary fibrosis. He was initially diagnosed with severe group 3 PH and received sildenafil, which generated a favorable hemodynamic response. However, 5 years later, his pulmonary hemodynamics deteriorated, and he died at the age of 67. An autopsy was performed, and thickening of alveolar septa and capillary proliferation, pathological features of PCH, were extensively observed in both lungs. We discuss when PCH developed, how sildenafil improved his hemodynamics, and how PCH could be clinically detected by noninvasive evaluations.

A rare case of cavernous hemangioma accompanied with diffuse hepatic hemangiomatosis.

BACKGROUND: Hepatic cavernous hemangioma (CH) is the most common hepatic benign tumor. Most cases are solitary, asymptomatic, and found incidentally. In symptomatic cases with rapidly growing tumors and coagulopathy, surgical treatment is considered. In rare cases, diffuse hepatic hemangiomatosis (DHH) is reported as a comorbidity. The etiology of DHH is unknown. CASE PRESENTATION: A 29-year-old female patient had a history of endometriosis treated with oral contraceptives. Hepatic CH was incidentally detected in the segment IVa of the liver according to the Couinaud classification. Follow-up computed tomography (CT) and ultrasound sonography showed the growth of the lesion and formation of multiple new lesions near the first. Enhanced CT and magnetic resonance imaging (MRI) revealed that the new lesions were different from CH. Although oral contraceptives were stopped, all lesions grew in size. Malignancy and possibility of rupture of these tumors were considered due to the clinical course, and we opted for surgical removal of the tumors. Left liver lobectomy and cholecystectomy were performed. Surgical findings were small red spot spreading and a mass in segment IV of the liver. Pathological examination revealed a circumscribed sponge-like tumor with diffuse irregular extension to the adjacent area. Both of the lesions consisted of blood-filled dilated vascular spaces lined by flat endothelium without atypia. The diagnosis was hepatic CH with DHH. The patient was discharged on postoperative day 12 uneventfully. CONCLUSION: We report the successful resection of CH with DHH. The case findings suggest a relationship between oral contraceptive use and enlargement of CH and DHH. Although DHH has been poorly understood, a few previously published cases reported DHH occurrence in patients using oral contraceptives. In such cases, the decision to perform surgical resection should be made after careful examination.

Laparoscopic posterior pelvic exenteration for primary adenocarcinoma of the rectovaginal septum without associated endometriosis: A case report.

The present report describes a case of laparoscopic posterior pelvic exenteration of a primary adenocarcinoma of the rectovaginal septum (PARS) without associated endometriosis. A 49-year-old woman was admitted to hospital for rectal bleeding. Imaging studies showed a 7-cm solid tumor located in the rectovaginal septum, presenting with invasion to the posterior aspect of the uterine cervix and the anterior rectal wall. The patient received laparoscopic posterior exenteration and rectosigmoid anastomosis followed by chemotherapy. There were no intra- or post-operative complications. Histopathological examination of the neoplastic tissue revealed moderate to severe cytological atypia with bizarre multinucleated cells and prominent mitotic figures. Histopathologically, R0 resection was achieved. No endometriotic lesions were confirmed in the primary tumor or other removed tissues. Immunohistochemistry showed positive staining for cytokeratin (CK)7, cancer antigen 125, vimentin, estrogen receptor and p53, but negative staining for CK20, progesterone receptor, p40 and thyroid transcription factor 1. Based on these findings and on the location of the tumor, the neoplasm was diagnosed as PARS without associated endometriosis, which may have arisen from metaplasia of the embryological Müllerian-duct remnants.

Clinicopathological significance of PSF3 expression in uterine endometrial carcinomas.

PSF3 (Partner of SLD Five 3) is a member of the heterotetrameric complex termed GINS. Previous studies have shown that PSF3 is up-regulated in several cancers and is associated with tumor malignancy. However, the clinicopathological significance of PSF3 expression in endometrial lesions is still poorly understood. To investigate whether PSF3 could serve as a useful biomarker for endometrial carcinomas, we performed immunohistochemical analysis of PSF3 expression. In 155 cases of endometrial carcinomas (ECs), the mean tumor proportion score of PSF3 expression was 30.7% in G1 endometrioid carcinoma, 55.0% in G2 endometrioid carcinoma, 59.0% in G3 endometrioid carcinoma, and 58.9% in nonendometrioid carcinomas. In 25 cases of atypical hyperplasia, the mean tumor proportion score of PSF3 expression was significantly lower (10.4%). High expression of PSF3 was associated with more advanced pathologic T stage (P = .000), lymphatic invasion (P = .001), and poor clinical outcomes such as shorter relapse-free survival (P = .000) and overall survival (P = .001). When we compared the immunostaining of PSF3 and Ki-67, the proportions of PSF3-positive cells in tumor epithelial cells were comparable to those of Ki-67-positive cells. However, PSF3-positive cells were selectively found in tumor cells, whereas Ki-67-positive cells were also found in tumor stromal cells. These results demonstrated that PSF3 immunostaining was valuable as a histopathologic marker for differential diagnosis between atypical hyperplasia and ECs, for tumor histologic grading, and for determining a patient's prognosis. PSF3 may play a crucial role in tumor progression in EC.

Expression of cathepsins V and S in thymic epithelial tumors.

Cathepsins are a group of proteolytic enzymes of the endosomal/lysosomal pathway involved in the thymic development of T cells restricted by major histocompatibility complex class II molecules. In the normal thymus, cathepsin V (CTV) and cathepsin S (CTS) are expressed in cortical and medullary epithelial cells, respectively. To investigate whether cathepsins could serve as a diagnostic marker, we performed immunohistochemical analysis for CTV and CTS in 77 cases of thymic epithelial tumors. Almost all cases (59/60) of thymoma expressed CTV, whereas 28 of 60 cases of thymoma expressed CTS. Notably, CTS was expressed in most cases of type A and type AB thymomas, but not in type B thymoma. The expression of cathepsins in type AB thymoma showed a clear correlation with histologic features; CTV was found predominantly in the type B component, and CTS was frequently expressed in the type A component. In thymic carcinoma, CTV was expressed in less than half cases (7/17), and the ratio of CTS-positive cases was equivalent to that of thymoma (8/17). Cases of CTV-negative thymic carcinoma tended to have a higher incidence of recurrence than did CTV-positive cases. Although further studies with a larger number of cases are required to confirm the utility of cathepsin immunostaining, CTV and CTS appear to serve as auxiliary diagnostic and/or prognostic markers in thymic epithelial tumors.

Fatal cardiac small-vessel involvement in ANCA-associated vasculitis: an autopsy case report.

An 80-year-old Japanese man, who had fever and generalized fatigue not improved by antibiotics, was admitted to our hospital. Laboratory data indicative of renal dysfunction and antineutrophil cytoplasmic antibody (ANCA) in the serum led to the consideration of ANCA-associated vasculitis as a differential diagnosis. However, before the diagnostic confirmation, he was found dead on the bed. Autopsy revealed necrotizing crescentic glomerulonephritis in the kidneys. In addition, necrotizing granulomatous vasculitis with infiltration of multinucleated giant cells and neutrophils but not eosinophils was present in multiple organs. The direct cause of death was presumed as cardiac arrest by lethal arrhythmia because vasculitic lesions were distributed widely in the cardiac walls, acute congestion was observed in the systemic organs, and other causes of death were ruled out. This report presents the unusual manifestation of cardiac small-vessel involvement in ANCA-associated vasculitis related to sudden death.

The SKINT1-like gene is inactivated in hominoids but not in all primate species: implications for the origin of dendritic epidermal T cells.

Dendritic epidermal T cells, which express an invariant Vγ5Vδ1 T-cell receptor and account for 95% of all resident T cells in the mouse epidermis, play a critical role in skin immune surveillance. These γδ T cells are generated by positive selection in the fetal thymus, after which they migrate to the skin. The development of dendritic epidermal T cells is critically dependent on the Skint1 gene expressed specifically in keratinocytes and thymic epithelial cells, suggesting an indispensable role for Skint1 in the selection machinery for specific intraepithelial lymphocytes. Phylogenetically, rodents have functional SKINT1 molecules, but humans and chimpanzees have a SKINT1-like (SKINT1L) gene with multiple inactivating mutations. In the present study, we analyzed SKINT1L sequences in representative primate species and found that all hominoid species have a common inactivating mutation, but that Old World monkeys such as olive baboons, green monkeys, cynomolgus macaques and rhesus macaques have apparently functional SKINT1L sequences, indicating that SKINT1L was inactivated in a common ancestor of hominoids. Interestingly, the epidermis of cynomolgus macaques contained a population of dendritic-shaped γδ T cells expressing a semi-invariant Vγ10/Vδ1 T-cell receptor. However, this population of macaque T cells differed from rodent dendritic epidermal T cells in that their Vγ10/Vδ1 T-cell receptors displayed junctional diversity and expression of Vγ10 was not epidermis-specific. Therefore, macaques do not appear to have rodent-type dendritic epidermal T cells despite having apparently functional SKINT1L. Comprehensive bioinformatics analysis indicates that SKINT1L emerged in an ancestor of placental mammals but was inactivated or lost multiple times in mammalian evolution and that Skint1 arose by gene duplication in a rodent lineage, suggesting that authentic dendritic epidermal T cells are presumably unique to rodents.

Decreased expression of thymus-specific proteasome subunit ß5t in Down syndrome patients.

AIMS: The majority of patients with Down syndrome (DS), trisomy 21, have morphologically abnormal thymuses and present with intrinsic immunological abnormalities affecting mainly the cellular immune response. The aim of this study was to examine whether the expression of functionally important molecules is altered in thymic stromal cells in patients with DS. METHODS AND RESULTS: We analysed thymic tissues from patients with trisomy 13 (n = 4), trisomy 18 (n = 14) and trisomy 21 (n = 13) for histological alterations, and for the expression of functionally important molecules such as ß5t, a thymoproteasome subunit, and cathepsins L and S. In patients with trisomy 13 and trisomy 18, the thymus was morphologically normal or showed only mild depletion of cortical thymocytes. In contrast, the thymus showed variable histological changes in patients with trisomy 21; six of 13 cases showed severe depletion of thymocytes accompanied by the disappearance of thymic lobular architecture. In such thymuses, spindle-shaped keratin-positive cells were densely distributed, and expression of ß5t, but not of cathepsin L, was markedly decreased. CONCLUSIONS: The present study suggests that abnormal thymic architecture and decreased expression of functionally important molecules in thymic stromal cells may be involved in immunological abnormalities in DS patients.

Immunohistochemical validation and expression profiling of NKG2D ligands in a wide spectrum of human epithelial neoplasms.

The MHC class I-chain-related proteins (MICs) and the UL16-binding proteins (ULBPs) are inducible stress response molecules that work as activators of a specific receptor, NKG2D, which is expressed on effector cells, such as NK cells and subsets of T cells. In this study, we sought to explore the biological significance of NKG2D ligands in human neoplasms by comprehensively examining the immunohistochemical expression profile of NKG2D ligands in a variety of human epithelial neoplasms. Following careful validation of the immunohistochemical specificity and availability of anti-human ULBP antibodies for formalin-fixed paraffin-embedded (FFPE) materials, the expression of NKG2D ligands was analyzed in FFPE tissue microarrays comprising 22 types of epithelial neoplastic tissue with their non-neoplastic counterpart from various organs. Hierarchical cluster analysis demonstrated a positive relationship among ULBP2/6, ULBP3, ULBP1, and ULBP5, whose expression patterns were similar across all of the neoplastic tissues examined. In contrast, MICA/B, as well as ULBP4, did not appear to be related to any other ligand. These expression profiles of NKG2D ligands in human neoplasms based on well-validated specific antibodies, followed by hierarchical cluster analysis, should help to clarify some functional aspects of these molecules in cancer biology, and also provide a path to the development of novel tumor-type-specific treatment strategies.

Hepatosplenic gamma-delta T-cell lymphoma associated with Epstein-Barr virus.

Hepatosplenic gamma-delta T-cell lymphoma (HSTCL) is a rare, aggressive subset of peripheral T-cell lymphoma. It has been reported that Epstein-Barr virus (EBV) infection can cause HSTCL; however, such cases are extremely rare, with only a few cases having been reported to date. We herein report an autopsy case of HSTCL associated with EBV infection. The presence of EBV infection was confirmed in serum EBV DNA and on in-situ hybridization, and cytotoxic molecules, such as granzyme B, perforin and T-cell intracytoplasmic antigen (TIA)-1, were all positive in lymphoma cells. These findings indicate that stimulation of persistent EBV infection may have caused HSTCL in this patient.

MICA/B expression in macrophage foam cells infiltrating atherosclerotic plaques.

Infiltrating macrophages accumulate in fatty streak lesions and transform into foam cells, leading to the formation of atherosclerotic plaques. Inflammatory mechanisms underlying the plaque formation mediated by NKG2D-positive lymphocytes such as CD8+ T cells, natural killer cells and natural killer T cells have been extensively investigated. Yet, the involvement of the NKG2D system itself remains poorly understood. Recent work in mouse models has shown that blockade of an NKG2D receptor-ligand interaction reduces plaque formation and suppresses inflammation in aortae. In this study, we conducted immunohistochemical analysis of NKG2D ligand expression in autopsy-derived aortic specimens. Foam cells expressing NKG2D ligands MICA/B were found in advanced atherosclerotic lesions accompanied by a large necrotic core or hemorrhage. Human monocyte-derived macrophages treated in vitro with acetylated low-density lipoproteins enhanced expression of MICA/B and scavenger receptor A, thus accounting for NKG2D ligand expression in foam cells infiltrating atherosclerotic plaques. Our results suggest that, as in mice, the NKG2D system might be involved in the development of atherosclerosis in humans.

Ovarian abnormalities in a mouse model of fragile X primary ovarian insufficiency.

FMR1 premutation (PM) alleles have 55-200 CGG·CCG-repeats in their 5' UTR. PM carriers are at risk of fragile X-associated tremor and ataxia syndrome (FXTAS). Females are also at risk for FX primary ovarian insufficiency (FXPOI). PM pathology is generally attributed to deleterious properties of transcripts with long CGG-tracts. For FXPOI, hormone changes suggest a reduced residual follicle pool. Whether this is due to a smaller than normal original follicle pool or an increased rate of follicle depletion is unclear. A FX-PM mouse the authors generated with 130 CGG·CCG-repeats in the endogenous Fmr1 gene recapitulates features of FXTAS. Here the authors demonstrate that the gross development of the ovary and the establishment of the primordial follicle pool is normal in these mice. However, these animals show a faster loss of follicles of all follicle classes, suggesting that the problem is intrinsic to the ovary. In addition, many oocytes show aberrant nuclear accumulation of FMRP and elevated levels of ubiquitination. Furthermore, PM follicles are smaller and have fewer granulosa cells (GCs) than normal. Thus, these animals have ovarian abnormalities involving both the oocytes and GCs that may shed light on the molecular basis of FXPOI in humans.

Involvement of an NKG2D ligand H60c in epidermal dendritic T cell-mediated wound repair.

Dendritic epidermal T cells (DETCs) found in mouse skin are NKG2D-positive γδ T cells involved in immune surveillance and wound repair. It is assumed that the interaction of an NKG2D receptor on DETCs and an MHC class I-like NKG2D ligand on keratinocytes activates DETCs, which then secrete cytokines promoting wound repair. However, direct evidence that DETC activation through NKG2D signaling promotes wound repair is not available. In the present study, we generated mAbs for an NKG2D ligand H60c previously suggested to be expressed specifically on skin keratinocytes. Local administration of H60c-specific mAb inhibited activation of DETCs and significantly delayed wound repair. Likewise, administration of NKG2D-specific mAb impaired wound repair to a similar extent. The delay in wound closure resulting from the blockade of the NKG2D pathway was comparable to that observed in γδ T cell-deficient mice. These results indicate that H60c/NKG2D interactions play a critical role in wound repair. Reassessment of binding affinities showed that H60c monomers bind to NKG2D with affinity (K(d) = 26 ± 3.2 nM) comparable to those of other high-affinity NKG2D ligands. H60c is transcribed not only in skin but also in tissues such as tongue and female reproductive tract known to contain epithelium-resident γδ T cells expressing invariant TCRs, suggesting a more general role for H60c in the maintenance of epithelial integrity.