Vairogdziedzera autoimunitāte: ar Th17-asociēto citokīnu un patomorfoloģisko mehānismu izpēte Hašimoto tireoidīta un Greivsa slimības patoģenēzē. Promocijas darba kopsavilkums

Pēdējo dekāžu laikā ievērojami pieaugusi tādu autoimūno vairogdziedzera slimību (AIVS) kā Greivsa slimība (GS) un Hašimoto tireoidīts (HT) saslimstība un izplatība. Ir būtiski identificēt imunoloģiskos un patomorfoloģiskos faktorus, kas iesaistīti vairogdziedzera autoimunitātes izcelsmē. Lai gan 1. un 2. tipa T līdzētājšūnu (Th) izmainīta aktivitāte AIVS patoģenēzē uzskatāma par pierādītu, nesen veiktie pētījumi liecina arī par iespējamu Th17 šūnu lomu AIVS attīstībā. Turklāt Th šūnu diferenciāciju var ietekmēt selēna deficīts, veicinot šūnu un humorālās imūnatbildes disfunkciju. Šī promocijas darba mērķis bija izpētīt Th17 šūnu nozīmi HT un GS patoģenēzē, lietojot dažādas morfoloģiskās diagnostikas metodes un xMAP tehnoloģiju, kā arī korelēt iegūtos datus ar selēna statusu. Sākotnēji pētījumā tika iekļauti 29 pieauguši pacienti ar AIVS, kuriem veikta tireoīdektomija, savukārt pētījuma klīniskā daļa ietvēra 52 pacientus ar pirmreizēji diagnosticētu, iepriekš neārstētu AIVS, kā arī 26 klīniski veselas pētāmās personas, kuras iekļautas kontroles grupā. Lai izvērtētu ar Th17 saistītu imūnatbildi AIVS ietvaros, tika mērīts ar Th17 saistīto citokīnu – interleikīna (IL)-17, IL-22, IL-23, IL-6 un IL-10 – līmenis plazmā, kā arī IL-17, IL-23 un IL-1β imūnekspresijas izplatība un līmenis vairogdziedzera audos. Vairogdziedzera folikulu integritāte tika pētīta, analizējot blīvo šūnu savienojumu jeb slēgjūgļu proteīnu zonula occludens-1 un klaudīna-1 imūnekspresiju un korelējot iegūtos datus ar IL-17 un CD68 ekspresiju. Papildus tam tika noteikts selēna statuss plazmā. Starp AIVS un kontroles grupas pacientiem statistiski ticamas ar Th17 saistīto citokīnu plazmas līmeņa atšķirības netika konstatētas. Tomēr IL-17 ekspresijas līmenis tireocītos bija ievērojami augstāks pacientiem ar HT un GS nekā kontroles grupas pētāmajām personām, vienlaicīgi korelējot ar IL-23 un IL-1β imūnpozitivitāti HT grupā. Tika noteikta statistiski nozīmīga pozitīva korelācija starp ar Th17 saistīto citokīnu līmeni plazmā un hipertireozes smaguma pakāpi, kas bija neatkarīga no autoantivielu līmeņa, tādējādi norādot uz to iespējamo lomu GS patoģenēzē. HT pacientu vairogdziedzera audos tika novērotas tireocītu slēgjūgļu molekulārās pārmaiņas, uzsverot vairogdziedzera folikulu integritātes bojājumu, taču to saistība ar IL-17 netika konstatēta. Nozīmīgai vairogdziedzera enzīmu daļai, kura nodrošina gan antioksidatīvo un pretiekaisuma funkciju, gan aktivē vairogdziedzera hormonus mērķa audos, funkcionālai aktivitātei nepieciešams pietiekams daudzums selēna, tādēļ selēna deficīts tiek saistīts ar AIVS patoģenēzi un pat terapiju. Lai gan mūsu pētījumā starp AIVS pacientiem un kontroles grupu netika noteiktas statistiski nozīmīgas atšķirības plazmas selēna līmenī, rezultāti pierāda, ka selēna statuss plazmā pirmreizēji diagnosticētiem GS un HT pacientiem Latvijā ir suboptimāls. Analizējot selēna līmeni plazmā HT pacientiem, iegūta statistiska nozīmīga negatīva asociācija ar autoantivielu pret tireoperoksidāzi (TPO) titru, tādējādi liecinot par selēna imūnmodulējošo lomu AIVS patoģenēzē. Turklāt HT pacientiem ar augstāku autoantivielu pret TPO līmeni tika novērots zemāks selēna līmenis plazmā, kas liek domāt, ka selēna papildterapija šiem pacientiem var sniegt ieguvumus. Veicot šo pētījumu, tika iegūta nozīmīga informācija, kas padziļina mūsu zināšanas par vairogdziedzera autoimunitātes patoģenēzi, kā arī ar Th17 saistīto citokīnu lomu un regulatoro ietekmi, tomēr būtu nepieciešami turpmāki pētījumi, lai vēl precīzāk izpētītu Th17 šūnu lomu AIVS patoģenēzē. Pētījums apstiprina arī nepietiekamu selēna līmeni plazmā AVS pacientiem, tomēr, lai izprastu saistību starp selēna papildterapiju un imūnatbildes reakciju, nepieciešams iegūt vairāk klīnisko pētījumu datu.

Decreased ZO1 expression causes loss of time-dependent tight junction function in the liver of ob/ob mice

Diabetes patients are at a high risk of developing complications related to angiopathy and disruption of the signal transduction system. The liver is one of the multiple organs damaged during diabetes. Few studies have evaluated the morphological effects of adhesion factors in diabetic liver. The influence of diurnal variation has been observed in the expression and functioning of adhesion molecules to maintain tissue homeostasis associated with nutrient uptake. The present study demonstrated that the rhythm-influenced functioning of tight junction was impaired in the liver of ob/ob mice. The tight junctions of hepatocytes were loosened during the dark period in normal mice compared to those in ob/ob mice, where the hepatocyte gaps remained open throughout the day. The time-dependent expression of zonula occludens 1 (ZO1) in the liver plays a vital role in the functioning of the tight junction. The time-dependent expression of ZO1 was nullified and its expression was attenuated in the liver of ob/ob mice. ZO1 expression was inhibited at the mRNA and protein levels. The expression rhythm of ZO1 was found to be regulated by heat shock factor (HSF)1/2, the expression of which was reduced in the liver of ob/ob mice. The DNA-binding ability of HSF1/2 was decreased in the liver of ob/ob mice compared to that in normal mice. These findings suggest the involvement of impaired expression and functioning of adhesion factors in diabetic liver complications.

Beneficial Effects of Quercetin on Microcystin-LR Induced Tight Junction Defects

Quercetin has numerous functions including antioxidant and anti-inflammatory effects. The beneficial effect of quercetin against microcystin-LR (MC-LR)-induced testicular tight junctions (TJs) defects in vitro and in vivo were investigated. Significant reductions in transepithelial electrical resistance, occludin, and zonula occludens-1(ZO-1) levels were detected in the MC-LR-treated TM4 cells, and quercetin attenuated these effects. Interestingly, quercetin suppressed MC-LR-induced phosphorylation of protein kinase B (AKT). It effectively inhibited the accumulation of reactive oxygen species (ROS) in cells stimulated by MC-LR. In addition, ROS inhibitors blocked the TJ damage that is dependent on the AKT signaling pathway induced by MC-LR. In conclusion, our results suggest that alleviates MC-LR-impaired TJs by suppressing the ROS-regulated activation of the AKT pathway.

The Cx43 Carboxyl-Terminal Mimetic Peptide αCT1 Protects Endothelial Barrier Function in a ZO1 Binding-Competent Manner

The Cx43 carboxyl-terminus (CT) mimetic peptide, αCT1, originally designed to bind to Zonula Occludens 1 (ZO1) and thereby inhibit Cx43/ZO1 interaction, was used as a tool to probe the role of Cx43/ZO1 association in regulation of epithelial/endothelial barrier function. Using both in vitro and ex vivo methods of barrier function measurement, including Electric Cell-Substrate Impedance Sensing (ECIS), a TRITC-dextran Transwell permeability assay, and a FITC-dextran cardiovascular leakage protocol involving Langendorff-perfused mouse hearts, αCT1 was found to protect the endothelium from thrombin-induced breakdown in cell–cell contacts. Barrier protection was accompanied by significant remodeling of the F-actin cytoskeleton, characterized by a redistribution of F-actin away from the cytoplasmic and nuclear regions of the cell, towards the endothelial cell periphery, in association with alterations in cellular chiral orientation distribution. In line with observations of increased cortical F-actin, αCT1 upregulated cell–cell border localization of endothelial VE-cadherin, the tight junction protein Zonula Occludens 1 (ZO1), and the Gap Junction Protein (GJ) Connexin43 (Cx43). A ZO1 binding-incompetent variant of αCT1, αCT1-I, indicated that these effects on barrier function and barrier-associated proteins, were likely associated with Cx43 CT sequences retaining ability to interact with ZO1. These results implicate the Cx43 CT and its interaction with ZO1, in the regulation of endothelial barrier function, while revealing the therapeutic potential of αCT1 in the treatment of vascular edema.

Morphological Features of the Testis among Autoimmune Mouse Model and Healthy Strains

Autoimmune diseases play a critical role in the progression of infertility in both sexes and their severity has been reported to increase with age. However, few reports have discussed their effect on the morphological features of the testis. Therefore, we compared the morphological alterations in the testes of autoimmune model mice (MRL/MpJ-Faslpr) and the control strain (MRL/MpJ) with those of their background strain (C57BL/6N) at 3 and 6 months. Furthermore, we analyzed the changes in spermatocytes, Sertoli cells, immune cells, and Zonula occludens-1 junctional protein by immunohistochemical staining. The MRL/MpJ-Faslpr mice showed a significant increase in the serum Anti-double stranded DNA antibody level, relative spleen weight, and seminiferous luminal area when compared with other studied two strains. In contrast, a significant decrease in the relative testis weight, and numbers of both Sertoli, meiotic spermatocyte was observed in MRL/MpJ-Faslpr and MRL/MpJ mice compared with C57BL/6N mice especially at 6 months. Similarly, Zonula occludens-1 junctional protein positive cells showed a significant decrease in the same strains at 6 months. However, no immune cell infiltration could be observed among the studied three strains. Our findings suggest that the increase in autoimmune severity especially with age could lead to infertility through loss of spermatogenic and Sertoli cells, rather than the disturbance of the blood–testis barrier.

Tight junction protein ZO-1 in Kawasaki disease

Background Kawasaki disease (KD) is a form of systemic febrile vasculitis that is complicated with coronary artery lesions (CAL). The tight junctions that maintain the intestinal barrier also play a role in systemic inflammatory diseases. Serum zonula occludens-1 (ZO-1) expression was found to be significantly lower in asthmatic patients, and another study reported that elevated systemic ZO-1 was positively correlated with inflammation in cirrhotic patients. A murine model of KD vasculitis demonstrated that vasculitis depended on intestinal barrier dysfunction, which is maintained by tight junctions. In this study, we aimed to investigate the role of the tight junction zonula occludens-1 (ZO-1) in the treatment response of intravenous immunoglobulin (IVIG) and the occurrence of CAL formation in KD patients. Methods We enrolled 40 KD patients, 12 healthy controls, and 12 febrile controls in this study. The serum levels of tight junction ZO-1 were determined by enzyme-linked immunosorbent assay. Results The serum ZO-1 level was higher in the fever control group but did not reach a statistical significance. KD patients who received a second dose of IVIG treatment due to initial IVIG unresponsiveness had a higher serum levels of tight junction ZO-1, but without statistical significance (2.15 ± 0.18 vs. 2.69 ± 0.31 ng/mL, p = 0.058). KD patients who developed a CAL demonstrated a significant lower serum tight junction ZO-1 levels than KD without CAL formation (1.89 ± 0.16 vs. 2.39 ± 0.15 ng/mL, p = 0.027). After multiple logistic regression analysis, ZO-1 levels [(95% confidence interval (CI): 0.058 ~ 0.941, odds ratio (OR) = 0.235, p = 0.041)] showed as the risk factor for CAL formation. Conclusion Serum levels of tight junction ZO-1 levels were lower in KD patients than fever controls and associated with CAL formation.

Expression of Tight Junction Proteins Is Altered in Bladder Cancer

Bladder cancer (BC) is one of the tumors which occur most frequently in urological system, but less is known about the expression of tight junction proteins and its clinical significance in BC. In this study, expression of claudin-4, zonula occludens-1 (ZO-1) and zonula occludens-1 nucleic acid-binding protein (ZONAB), in BC tissues, adjacent nontumor tissue (ANTT), and BC cell lines was examined by Western blotting, semiquantitative RT-PCR, and immunohistochemistry, and then, the clinical significance of these proteins was investigated. The mRNA and protein expression of ZONAB were significantly upregulated, while those of ZO-1 was significantly downregulated in some BC cell lines and tissues in comparison with nontumor urothelial cell lines and ANTT. High expression rate of ZO-1 and ZONAB had negative correlation in BC tissues and was also correlated with muscle-invasive lesions in BC tissues. In conclusion, the expression of tight junction proteins is significantly altered in BC and ZO-1, and ZONAB interaction might be involved in BC development.