C-Terminal Domain of Aquaporin-5 Is Required to Pass Its Protein Quality Control and Ensure Its Trafficking to Plasma Membrane

Aquaporin-5 (AQP5) is selectively expressed in the apical membrane of exocrine glands, such as salivary, lacrimal, and submucosal glands. It is important for the secretory function of exocrine glands because mice with the knockout of AQP5 exhibit a significant reduction in secretion from these glands. Previous reports indicated that the AQP5 C-terminal domain is crucial for the localization of AQP5 at the plasma membrane, but it remains unclear which motif or amino acid residues in the C-terminal domain are essential for this. In this study, we examined the effects of various AQP5 C-terminal deletions or mutations on the expression of AQP5 on the cell surface. AQP5 C-terminal domain mutants did not localize on the plasma membrane, and Leu262 was shown to be crucial for AQP5′s plasma membrane localization. The mutants localized in the autophagosome or lysosome and showed decreased protein stability via lysosomal degradation. Taking these findings together, our study suggests that the C-terminal domain is required for AQP5 to pass protein quality control and be trafficked to the plasma membrane.

Male and Female Cloacal Anatomy of the Fischer’s Clawed Salamander, Onychodactylus fischeri (Caudata, Hynobiidae)

The cloaca of salamanders is a complex organ with exocrine glands involved in the production of sex pheromones, spermatophores, and storage of sperm. Since the cloaca provides reproductive functions, its signs are important for phylogenetic analysis in the evolutionary biology of tailed amphibians. For clarification of intrafamilial variation of cloacal characteristics in hynobiids, we studied the anatomy of male and female cloacae of Onychodactylus fischeri via histological, histochemical, and 3D-reconstruction methods. Males and females had ciliated cloacal linings and with sexual dimorphism in cloacal conformation and cloacal glands. As in other males and females of hynobiids, females of O. fischeri possessed only ventral glands, secreting neutral glycoproteins. In contrast, males of this species had three types of the cloacal glands. Glands «B» were like ventral glands of females and other hynobiids, while glands «A» and «C» had different histochemical and morphological characteristics. As our results are generally consistent with the data for the related species O. japonicus, these characteristics of the male and female cloacal anatomy may be common to all species of the genus Onychodactylus. The presence of three types of unique cloacal glands in males distinguishes Onychodactylus from all other hynobiids and salamanders.

The Multiple Roles of B Cells in the Pathogenesis of Sjögren’s Syndrome

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disease characterized by lymphocytic infiltration and tissue destruction of exocrine glands such as salivary glands. Although the formation of ectopic lymphoid tissue in exocrine glands and overproduction of autoantibodies by autoreactive B cells highlight the critical involvement of B cells in disease development, the precise roles of various B cell subsets in pSS pathogenesis remain partially understood. Current studies have identified several novel B cell subsets with multiple functions in pSS, among which autoreactive age-associated B cells, and plasma cells with augmented autoantibody production contribute to the disease progression. In addition, tissue-resident Fc Receptor-Like 4 (FcRL4)+ B cell subset with enhanced pro-inflammatory cytokine production serves as a key driver in pSS patients with mucosa-associated lymphoid tissue (MALT)-lymphomas. Recently, regulatory B (Breg) cells with impaired immunosuppressive functions are found negatively correlated with T follicular helper (Tfh) cells in pSS patients. Further studies have revealed a pivotal role of Breg cells in constraining Tfh response in autoimmune pathogenesis. This review provides an overview of recent advances in the identification of pathogenic B cell subsets and Breg cells, as well as new development of B-cell targeted therapies in pSS patients.

Benign myoepithelioma of the soft palate: an unusual clinical entity

Myoepitheliomas are rare benign tumours that affect the exocrine glands and are sporadically located in the salivary glands. The most common location of myoepithelioma in the oral cavity is the parotid gland and it is seldom encountered in the palate. The diagnosis of this entity is challenging since its clinical presentation may resemble those of more common neoplasms, rendering a complex histopathological diagnosis. The aim of the present case report is to describe an unusual case of myoepithelioma of the soft palate in a male patient, which developed as an asymptomatic, slowly growing mass. The tumour was assessed with histopathological examination and the diagnosis was verified via immunohistochemistry. Finally, the treatment included surgical resection of the tumour and no signs of recurrence were noted 2.5 years after the surgical procedure. Early diagnosis and treatment plays an important role in the prognosis of this pathological entity.

A serendipitous case report of acute pancreatitis complicated by pseudocyst in a patient with COVID-19

Acute pancreatitis is a common gastrointestinal disease, most frequently requiring acute hospitalization. During SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) pandemic, the etiologic agent of COVID-19, several studies described the involvement of other tissues besides the respiratory tract, such as the gastrointestinal tract. In pancreas, ACE-2 receptor is expressed in exocrine glands and islets, both being targets for the virus and subsequent pancreatic injury. There are few articles which report pancreatic injury in COVID-19 patients but most of them do not report acute pancreatitis. Diagnosing acute pancreatitis in the setting of COVID-19 pandemic is challenging and requires ruling out all other potential causes of pancreatitis. Herein we report a rare case of severe acute pancreatitis.

Cutting the “Gordian Knot” — Cardiac Involvement in Primary Sjögren Syndrome

Sjögren syndrome (SS) is a systemic autoimmune disease typically characterized by inflammatory involvement of the exocrine glands1. The association of SS with an increased risk of cardiovascular disease (CVD) including manifestations such as stroke and myocardial infarction has been demonstrated by numerous previous studies1.

TO THE ULTRASTRUCTURAL ORGANIZATION OF EPITHELIOCYTES OF EXOCRINE GLANDS

Pieces of the sublingual multi-duct salivary glands of a domestic sexually mature large white pig were fixed in a 4 % paraform solution in 0.1 M phosphate buffer (pH = 7.4) with addi-tional fixation in a 1 % OsO4 solution, dehydrated in alcohols of increasing concentration. Taking into account the recommendations of G. Gayer, pieces of organs were poured into araldite accord-ing to the standard technique. Contrasting was performed according to Reynolds. In the cytoplasm of the mucocytes of the sublingual multi-duct salivary gland, the agranu-lar endoplasmic reticulum predominates, which gives oxyphilic staining. According to electron microscopic studies of mucous glandulocytes in the acini of the sub-lingual salivary glands of domestic pigs, the secretory vacuoles of the cytoplasm are large, with pro-nounced electron-dense membranes. The content of vacuoles in mucocytes of one acinus is differ-ent.

MANAGEMENT OF SJOGREN'S SYNDROME THROUGH AYURVEDA : A CASE STUDY

Sjögren's syndrome is a chronic, slowly progressing autoimmune disorder characterised by lymphocytic infiltration of exocrine glands resulting in xerostomia and dry eyes (conjunctivitis). 1) The disease can present as an entity alone or in association with other auto-immune diseases like Scleroderma, RA, SLE & auto-immune thyroid disease. 2) In this article, attempt is made to understand the Sjögren's syndrome & its treatment in ayurveda by considering the concept of udakvaha srotodushti, vyadhikshamatva and vatadhikya vatrakta. Keywords:Auto-immune, Vatadhikya Vatrakta, Sjögren's syndrome, Udakvaha srotodushti