The apical and basal environments of the retinal pigment epithelium regulate the maturation of tight junctions during development

Rahner, Christoph; Fukuhara, Masayuki; Peng, Shaomin; Kojima, S.; Rizzolo, Lawrence J.

doi:10.1242/jcs.01181

Cited by 51 publications

(35 citation statements)

References 46 publications

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“…Similarly, in polarized HepG2 cells we found that the basal and lateral pools of CLDN1 and JAM-A are Triton X-100 soluble, whereas TJ-associated CLDN1 and JAM-A are insoluble to detergent extraction (data not shown). The presence of TJ and nonjunctional pools of CLDNs in the liver is consistent with earlier reports (44). We hypothesize that nonjunctional CLDN1 may be more accessible to interact with the viral glycoproteins during entry.…”

Section: Discussionsupporting

confidence: 92%

Polarization Restricts Hepatitis C Virus Entry into HepG2 Hepatoma Cells

Mee

Harris

Farquhar

et al. 2009

J Virol

117

141

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The primary reservoir for hepatitis C virus (HCV) replication is believed to be hepatocytes, which are highly polarized with tight junctions (TJ) separating their basolateral and apical domains. HepG2 cells develop polarity over time, resulting in the formation and remodeling of bile canalicular (BC) structures. HepG2 cells expressing CD81 provide a model system to study the effects of hepatic polarity on HCV infection. We found an inverse association between HepG2-CD81 polarization and HCV pseudoparticle entry. As HepG2 cells polarize, discrete pools of claudin-1 (CLDN1) at the TJ and basal/lateral membranes develop, consistent with the pattern of receptor staining observed in liver tissue. The TJ and nonjunctional pools of CLDN1 show an altered association with CD81 and localization in response to the PKA antagonist Rp-8-Br-cyclic AMPs (cAMPs). Rp-8-Br-cAMPs reduced CLDN1 expression at the basal membrane and inhibited HCV infection, supporting a model where the nonjunctional pools of CLDN1 have a role in HCV entry. Treatment of HepG2 cells with proinflammatory cytokines, tumor necrosis factor alpha and gamma interferon, perturbed TJ integrity but had minimal effect(s) on cellular polarity and HCV infection, suggesting that TJ integrity does not limit HCV entry into polarized HepG2 cells. In contrast, activation of PKC with phorbol ester reduced TJ integrity, ablated HepG2 polarity, and stimulated HCV entry. Overall, these data show that complex hepatocyte-like polarity alters CLDN1 localization and limits HCV entry, suggesting that agents which disrupt hepatocyte polarity may promote HCV infection and transmission within the liver.Hepatitis C virus (HCV) poses a global health problem, with over 170 million infected individuals worldwide. The principal reservoir for HCV replication is believed to be hepatocytes in the liver. Innate and adaptive cellular immune responses are thought to play a critical role in controlling HCV replication. However, in the majority of cases, the virus persists and the resulting hepatitis leads to progressive liver injury, frequently culminating in fibrosis and hepatocellular carcinoma. At the present time there is no vaccine and the only established treatment is alpha interferon (IFN-␣) in combination with ribavirin, which is only partially effective. Hence, there is an urgent need for the development of more effective therapies.The recent discovery that some strains of HCV can replicate in cell culture (HCVcc) and release infectious particles has allowed the complete viral life cycle to be studied (30,52,58). HCV initiates infection by attaching to molecules or receptors at the cell surface, and current evidence suggests that the tetraspanin CD81 (3, 10, 20, 26), scavenger receptor class B member I (SR-BI) (2, 22, 48), and the tight junction (TJ) proteins claudin-1 (CLDN1) and occludin (OCLN) (15,37,43,55,57) are required for HCV entry (reviewed in reference 50). However, the exact role(s) played by each of the receptors is unclear.Many tissues in the body contain polarized cells,...

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Section: Discussionsupporting

confidence: 92%

Polarization Restricts Hepatitis C Virus Entry into HepG2 Hepatoma Cells

Mee

Harris

Farquhar

et al. 2009

J Virol

117

141

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“…In the eye of zebrafish, CLDN19 is specifically expressed in the retina, mainly in the retinal pigment epithelium (5). Its function in this epithelium remains unknown, but effective tight junction formation is required during normal retinal development (18). In our study, all patients had ocular involvement; however, its severity was far less significant.…”

Section: Discussionmentioning

confidence: 49%

Renal, Ocular, and Neuromuscular Involvements in Patients with CLDN19 Mutations

Faguer¹,

Chauveau²,

Pascal³

et al. 2011

Clinical Journal of the American Society of Nephrology

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SummaryBackground and objectives The objective of this study was to describe the renal and extrarenal findings in patients with recessively inherited familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) associated with CLDN19 mutations.Design, setting, participants, & measurements Medical records of three patients from two French unrelated families with CLDN19 mutations were retrospectively examined.Results Direct sequencing of CLDN19 identified a known variant (p.Gly20Asp) in all patients and a new missense mutation (p.Val44Met) in one (compound heterozygous). The patients' renal phenotype closely mimicked CLDN16-related nephropathy: low serum Mg 2ϩ (Ͻ0.65 mmol/L) despite oral supplementation, hypercalciuria partly thiazide-sensitive, and progressive renal decline with ESRD reached at age 16 and 22 years in two individuals. Primary characteristics (failure to thrive, recurrent urinary tract infections, or abdominal pain), age at onset (0.8 to 16 years), and rate of renal decline were highly heterogeneous. Ocular involvement was identified in all patients, although two patients did not have visual loss. Additionally, exercise intolerance with pain, weakness, and electromyographical alterations mimicking a Ca 2ϩ /K ϩ channelopathy (pattern V) were observed in two of three individuals. These features persisted despite the normalization of serum K ϩ and Mg 2ϩ after renal transplantation.Conclusions Ocular manifestations, even subtle, and exercise intolerance mimicking mild to moderate periodic paralysis are two symptoms that need to be searched for in patients with FHHNC and may indicate CLDN19 mutations.

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“…It is physiologically essential that the selective ‘leakage' of TJs is tissue specific [24]. Moreover, TJ structure and/or electrophysiological parameters are also known to be influenced by culture conditions [25]. The barrier function can be assessed by TER, which is mediated through the selective membrane conductance to potassium (K + ) and sodium ions (Na + ) induced by a polarized ion transporter distribution in mature epithelial monolayers of fetal RPE [26].…”

Section: Discussionmentioning

confidence: 99%

Effect of Novel Vital Dyes on Outer Blood-Retina Barrier Function in Cultured Human Retinal Pigment Epithelium

Liu

Meyer

Stanzel³

2013

Ophthalmologica

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Purpose: To assess tight junction (TJ) integrity in cultured human fetal retinal pigment epithelium (HFRPE) after exposure to clinically relevant novel vital dyes. Methods: HFRPE floater cells were harvested from RPE primary cultures of 4 donor eyes and seeded on polyester Transwell® for 4-6 weeks. The apical compartments of well-differentiated cultures were exposed to 0.005 mg/ml Coomassie violet R200 (CVR), methyl 2B (M2B) or Orange II. Periods of 30-300 s were chosen to mimic surgical exposure times, while 3 h was used for toxicity assays, with subsequent washout. Cell-cell junctions were studied by immunofluorescence (zonula occludens-1, ZO-1). Transepithelial electrical resistance (TER) was measured regarding blood-retina barrier (BRB) function. Results: At 4-6 weeks after confluence, HFRPE had grown into pigmented hexagonal monolayers with stable TER values (451-1,520 Ω·cm²). After 300-second dye treatments, a continuous ZO-1 signal was detected in all vital dye-treated groups 1.5 h after exposure, whereas trypsin controls showed patchy loss of the TJ stain. TER of CVR-, M2B- and Orange-II-treated groups had dropped 1.5 h after exposure to 148 ± 58.4, 162 ± 23.7 and 164 ± 18.5 Ω·cm², respectively, compared to 73 ± 44.9 Ω·cm² in positive controls. After 3 h of exposure to 0.005 mg/ml vital dyes in thick drops, TER maintained similar levels to those prior to exposure (90.8 ± 4.7% of the original values, 93.8 ± 6.5 and 91.9 ± 3.6%, respectively), together with no difference from the vehicle controls (94.8 ± 6.6%). TER values recovered in all groups to prior levels within 3 days. Conclusion: Novel vital dyes (CVR, M2B and Orange II) caused no outer BRB function alteration.

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The apical and basal environments of the retinal pigment epithelium regulate the maturation of tight junctions during development

Cited by 51 publications

References 46 publications

Polarization Restricts Hepatitis C Virus Entry into HepG2 Hepatoma Cells

Polarization Restricts Hepatitis C Virus Entry into HepG2 Hepatoma Cells

Renal, Ocular, and Neuromuscular Involvements in Patients with CLDN19 Mutations

Effect of Novel Vital Dyes on Outer Blood-Retina Barrier Function in Cultured Human Retinal Pigment Epithelium

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