CLDN5: From structure and regulation to roles in tumors and other diseases beyond CNS disorders

Area of Science:

• Molecular Biology
• Cell Biology
• Pathology

Background:

• Claudin-5 (CLDN5) is a key protein in tight junctions (TJs), essential for blood-brain barrier (BBB) integrity and central nervous system (CNS) homeostasis.
• While CLDN5's role in CNS diseases is established, its involvement in other pathologies is increasingly recognized.

Purpose of the Study:

• To review the structure, expression, and regulation of Claudin-5 (CLDN5).
• To focus on CLDN5's multifaceted roles in tumor growth, metastasis, and clinical significance.
• To provide an overview of CLDN5's involvement in respiratory, intestinal, cardiac, and diabetic ocular diseases.

Main Methods:

• Literature review synthesizing existing research on Claudin-5 (CLDN5).
• Analysis of CLDN5 expression patterns and regulatory mechanisms across various diseases.
• Examination of CLDN5's impact on cellular phenotypes and disease progression.

Main Results:

• CLDN5 is implicated not only in BBB integrity but also significantly in tumor progression and metastasis.
• Abnormal CLDN5 expression correlates with the development of diverse conditions, including respiratory, intestinal, cardiac, and diabetic ocular diseases.

Conclusions:

• Claudin-5 (CLDN5) is a critical regulator with diverse roles beyond the CNS, impacting tumorigenesis and multiple organ system diseases.
• Understanding CLDN5's complex functions and regulation is crucial for developing novel therapeutic strategies for a wide range of human pathologies.