Molecular biology of BPIFB1 and its advances in disease

Bactericidal/permeability-increasing (BPI)-fold-containing family B member 1 (BPIFB1), also known as long-palate lung and nasal epithelium clone 1 (LPLUNC1), belongs to the BPI-fold-containing family, is a newly discovered natural immune protection molecule, which, having the function of bactericidal and osmotic enhancement protein domain, can respond to the external physical and chemical stimuli. The gene of BPIFB1 is located at chromosome 20q11.21-20q11.22, and contains 16 exons and 15 introns, encoding 484 amino acids. The 5' terminal of the BPIFB1 protein has a signal peptide sequence composed of 19 amino acids. BPIFB1 is abnormally expressed in nasopharyngeal carcinoma (NPC), gastric cancer, and other cancer tissues, regulate chronic infections and inflammation, indicating that it may play an important role in the development of tumors. Meanwhile, BPIFB1 has well-recognized roles in sensing and responding to Gram-negative bacteria due to its structural similarity with BPI protein and lipopolysaccharide (LPS)-binding protein, both of which are innate immune molecules with recognized roles in sensing and responding to Gram-negative bacteria, so it can regulate cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), asthma, and other respiratory diseases. In this article, we will discuss the progress of BPIFB1 in a variety of diseases and fully understand its function.