Galectin-3 and prohibitin 1 are autoantigens in IgG4-related cholangitis without clear-cut protective effects against toxic bile acids.

Background and aims: IgG4-related cholangitis (IRC) is the hepatobiliary manifestation of IgG4-related disease, a systemic B cell-driven fibro-inflammatory disorder. Four autoantigens have recently been described in IgG4-RD: annexin A11, galectin-3, laminin 511-E8, and prohibitin 1. We have previously reported a protective role of annexin A11 and laminin 511-E8 in human cholangiocytes against toxic bile acids. Here, we explored the potentially protective role of the carbohydrate-binding lectin galectin-3 and the scaffold proteins prohibitins 1 and 2. Methods: Anti-galectin-3, anti-prohibitin 1 and 2 autoantibody positivity in IRC and healthy and disease (primary sclerosing cholangitis (PSC)) control sera was assessed by ELISA/liquid chromatography-tandem mass spectrometry (LC-MS/MS). Human H69 cholangiocytes were subjected to short hairpin RNA (shRNA) knockdown targeting galectin-3 (LGALS3), prohibitin 1 (PHB1), and prohibitin 2 (PHB2). H69 cholangiocytes were also exposed to recombinant galectin-3, the inhibitor GB1107, recombinant prohibitin 1, and the pan-prohibitin inhibitor rocaglamide. Protection against bile acid toxicity was assessed by intracellular pH (pHi) measurements using BCECF-AM, 22,23-3H-glycochenodeoxycholic acid (3H-GCDC) influx, and GCDC-induced apoptosis using Caspase-3/7 assays. Results: Anti-galectin-3 autoantibodies were detected in 13.5% of individuals with IRC but not in PSC. Knockdown of LGALS3 and galectin-3 inhibition with GB1107 did not affect pHi, whereas recombinant galectin-3 incubation lowered pHi. LGALS3 knockdown increased GCDC-influx but not GCDC-induced apoptosis. GB1107 reduced GCDC-influx and GCDC-induced apoptosis. Recombinant galectin-3 tended to decrease GCDC-influx and GCDC-induced apoptosis. Anti-prohibitin 1 autoantibodies were detected in 61.5% and 35.7% of individuals with IRC and PSC, respectively. Knockdown of PHB1, combined PHB1/2 KD, treatment with rocaglamide, and recombinant prohibitin 1 all lowered pHi. Knockdown of PHB1, PHB2, or combined PHB1/2 did not alter GCDC-influx, yet knockdown of PHB1 increased GCDC-induced apoptosis. Conversely, rocaglamide reduced GCDC-influx but did not attenuate GCDC-induced apoptosis. Recombinant prohibitin 1 did not affect GCDC-influx or GCDC-induced apoptosis. Finally, anti-galectin-3 and anti-prohibitin 1 autoantibody pretreatment did not lead to increased GCDC-influx. Conclusions: A subset of individuals with IRC have autoantibodies against galectin-3 and prohibitin 1. Gene-specific knockdown, pharmacological inhibition, and recombinant protein substitution did not clearly disclose a protective role of these autoantigens in human cholangiocytes against toxic bile acids. The involvement of these autoantibodies in processes surpassing epithelial secretion remains to be elucidated.

Colangitis biliar primaria. Parte 1. Actualización: generalidades, epidemiología, factores involucrados, fisiopatología y manifestaciones clínicas / Primary biliary cholangitis. Part 1. State of the art, epidemiology, physiopathology and clinical manifestations

La colangitis biliar primaria (CBP), es una colangiopatía crónica caracterizada por la destrucción selectiva de las células epiteliales biliares de conductos hepáticos de pequeño y mediano calibre, que afecta principalmente a mujeres. Los principales síntomas son la fatiga y el prurito, sin embargo, gran porcentaje de los pacientes pueden ser asintomáticos. El diagnóstico se basa en anticuerpos antimitocondriales (AMA) con títulos >1:40, fosfatasa alcalina >1,5 veces del límite superior normal por más de 24 semanas e histología hepática compatible con la patología. Se asocia con múltiples enfermedades principalmente de carácter autoinmune extra hepáticas, enfermedades tiroideas, óseas, entre otras. El tratamiento de primera línea es el ácido ursodesoxicólico (AUDC) que a pesar que no cura la enfermedad, mejora las pruebas del perfil hepático, así como el retraso en la progresión a cirrosis. Actualmente se encuentran en estudio nuevos tratamientos y terapias adyuvantes. El propósito de esta revisión es ofrecer una actualización de este tema que se presenta en los servicios de medicina interna y gastroenterología; para su realización se conformó un equipo interdisciplinario que desarrolló una búsqueda en la base Medline a través de PubMed con las palabras claves correspondientes y se procedió a una lectura crítica y analítica de títulos, resúmenes y textos completos para el filtro, extracción y síntesis de la información encontrada

Primary biliary cholangitis (PBC) is a chronic autoimmune cholangiopathy characterized by a selective destruction of biliary epithelial cells of small and medium caliber hepatic ducts, which mainly affects women. The main symptoms are fatigue and pruritus, however, a large proportion of patients may be asymptomatic. The diagnosis is based on AMA titers >1:40, alkaline phosphatase >1.5 times the upper limit for more than 24 weeks and compatible liver histology. It is associated with multiple autoimmune diseases mainly extrahepatic, thyroid diseases, bone diseases, among others. The first line treatment is ursodeoxycholic acid (UDCA), that improves liver function tests and delay the progression to cirrhosis. Currently, there are new treatments and adjuvant therapies on study. The purpose of this review is to offer an update in this topic, which is very important in gastroenterology and internal medicine. We formed an interdisciplinary team to search in the database Medline thorough PubMed with the key words describe below, we made a critical lecture of the titles and abstracts of each article to write this paper

Prevalencia de anticuerpos antinucleares en cirrosis biliar primaria, con anticuerpos antimitocondriales negativos / Primary biliar cirrhosis: patients eith autoimmune cholangitis ANA positive and AMA negative

Recientemente se describió en la literatura una subpoblación de pacientes con cirrosis biliar primaria (CBP) y anticuerpos antimitocondriales negativos [AAM(-)], que puede corresponder a pacientes con colangitis autoinmune con AAN(+). En este trabajo encontramos 25 casos (23 mujeres) con CBP y AAM(-), en las que 14 (56 por ciento) tuvieron AAN(+) a una dilución 1:40. Se determinaron bilirrubinas totales, transaminasas, AAM y AAN por inmunofluorescencia indirecta, considerándose como positivos títulos de 1:40. Cien por ciento tenían elevación de la fosfatasa alcalina (641 ñ 389 U/I). La bilirrubina estuvo por debajo de 2.5 en 59 por ciento. Trece pacientes tenían várices esofágicas. El estadio histológico fue I-II en once y III-IV en 14 casos. Corroboramos la existencia de una subpoblación de pacientes con CBP, AAM(-) y ANN(+) y confirmamos las observaciones de otros grupos con respecto a alteraciones inmunológicas diversas en pacientes con CBP.