The Essential Role of anxA2 in Langerhans Cell Birbeck Granules Formation

CD207 Expression Level is a New Prognostic Marker for Condyloma Acuminatum

Background

Condyloma cuminata (CA) is a sexually transmitted disease caused by human papillomavirus (HPV) infection, which is prone to recurrence and difficult to cure in the short term. CD207 is a C-type lectin receptor that is specifically expressed on the surface of Langerhans cells (LCs) and is considered as an LC-specific immunohistochemical marker. The main purpose of this study is to explore the correlation between the expression of CD207 in CA skin lesions and the duration of CA disease course and frequency of recurrence, in order to provide new prognostic markers for CA to clinicians.

Materials and Methods

A total of 40 male patients with CA and their skin lesions were collected, as well as 40 healthy male penile tissue samples. The skin lesions of CA were clinically and histologically confirmed by acetic acid test. The expression of CD207 in epidermal tissues was detected using immunohistochemistry. The difference in the number of CD207 positive cells between CA skin lesions and healthy skin controls was compared, and the association between the number of CD207 positive cells in CA skin lesions and the duration of disease course and the frequency of recurrence was determined through Spearman correlation analysis.

Conclusion

In CA skin lesions, CD207 positive cells were found to have morphological abnormalities and the number of cells was significantly reduced compared to healthy skin, suggesting that there may be antigen presentation dysfunction in CA skin lesions, which may be the reason for the prolonged and unresolved condition of the disease. The fewer CD207 positive cells in CA skin lesions, the longer the disease course and the more frequent the recurrence, therefore, the expression level of CD207 can be used as a new prognostic marker for predicting the outcome of CA.

Loss of ZNF148 enhances insulin secretion in human pancreatic β cells

Insulin secretion from pancreatic β cells is essential to the maintenance of glucose homeostasis. Defects in this process result in diabetes. Identifying genetic regulators that impair insulin secretion is crucial for the identification of novel therapeutic targets. Here, we show that reduction of ZNF148 in human islets, and its deletion in stem cell-derived β cells (SC-β cells), enhances insulin secretion. Transcriptomics of ZNF148-deficient SC-β cells identifies increased expression of annexin and S100 genes whose proteins form tetrameric complexes involved in regulation of insulin vesicle trafficking and exocytosis. ZNF148 in SC-β cells prevents translocation of annexin A2 from the nucleus to its functional place at the cell membrane via direct repression of S100A16 expression. These findings point to ZNF148 as a regulator of annexin-S100 complexes in human β cells and suggest that suppression of ZNF148 may provide a novel therapeutic strategy to enhance insulin secretion.

Cryo-electron tomography of Birbeck granules reveals the molecular mechanism of langerin lattice formation

Langerhans cells are specialized antigen-presenting cells localized within the epidermis and mucosal epithelium. Upon contact with Langerhans cells, pathogens are captured by the C-type lectin langerin and internalized into a structurally unique vesicle known as a Birbeck granule. Although the immunological role of Langerhans cells and Birbeck granules have been extensively studied, the mechanism by which the characteristic zippered membrane structure of Birbeck granules is formed remains elusive. In this study, we observed isolated Birbeck granules using cryo-electron tomography and reconstructed the 3D structure of the repeating unit of the honeycomb lattice of langerin at 6.4 Å resolution. We found that the interaction between the two langerin trimers was mediated by docking the flexible loop at residues 258–263 into the secondary carbohydrate-binding cleft. Mutations within the loop inhibited Birbeck granule formation and the internalization of HIV pseudovirus. These findings suggest a molecular mechanism for membrane zippering during Birbeck granule biogenesis and provide insight into the role of langerin in the defense against viral infection.

Special Issue "Recent Developments in Annexin Biology"

Discovered over 40 years ago, the annexin proteins were found to be a structurally conserved subgroup of Ca²⁺-binding proteins. While the initial research on annexins focused on their signature feature of Ca²⁺-dependent binding to membranes, over the years the biennial Annexin conference series has highlighted additional diversity in the functions attributed to the annexin family of proteins. The roles of these proteins now extend from basic science to biomedical research, and are being translated into the clinic. The research on annexins involves a global network of researchers, and the 10th biennial Annexin conference brought together over 80 researchers from ten European countries, USA, Brazil, Singapore, Japan and Australia for 3 days in September 2019. In this conference, the discussions focused on two distinct themes—the role of annexins in cellular organization and in health and disease. The articles published in this Special Issue cover these two main themes discussed at this conference, offering a glimpse into some of the notable findings in the field of annexin biology.