Disease relevance of PLUNC

• Isolation of a novel human lung-specific gene, LUNX, a potential molecular marker for detection of micrometastasis in non-small-cell lung cancer [1].
• Comparative analyses of the conventional histological examination and the RT-PCR detection assay for LUNX mRNA showed that the detection rate of metastases in lymph nodes by the RT-PCR assay was higher in 12 and consistent in 6 of the total 20 NSCLC patients [1].
• The findings suggest that SPLUNC1 is commonly expressed in adenocarcinomas, muco-epidermoid carcinoma, and bronchio-alveloar carcinoma, and is absent from small-cell carcinoma and squamous cell carcinoma [2].

High impact information on PLUNC

• PLUNC: a novel family of candidate host defence proteins expressed in the upper airways and nasopharynx [3].
• SPLUNC1 (PLUNC) is expressed in glandular tissues of the respiratory tract and in lung tumours with a glandular phenotype [2].
• Although SPLUNC1 is found in some epithelial cells of the upper airways and coats the surface epithelial cell lining of the major airways, the most significant site of protein localization is in mucous cells and ducts of submucosal glands [2].
• This expression pattern is consistent with the presumed phenotypic origin of these tumours and suggests that SPLUNC1 may be a useful marker for lung cancer [2].
• The protein was identified as palate, lung, nasal epithelium clone protein (PLUNC) [4].

Biological context of PLUNC

• A 25 kDa protein with pI 5.5 was found to be altered in the NLF 2-DE patterns; a trypsin digest of the 2-DE spot analyzed by MALDI-TOF and expressed sequence tags (ESTs) determined after post-source decay (PSD) identified the protein as palate lung and nasal epithelial clone (PLUNC) [5].
• In humans, PLUNC genes are located in a compact cluster on chromosome 20, with similar loci being found in synteneic locations in other species [6].
• In this article we use analysis of the human, mouse, and rat genomes and other sequence data to examine the relationships between the PLUNC family proteins from humans and other species, and between these proteins and members of the BPI family [7].
• Tissue distribution of the secretory protein, SPLUNC1, in the human fetus [8].
• Our research suggests that SPLUNC1 protein may not only be an antimicrobial peptide that plays an important role in the maintenance of homeostasis in the upper respiratory tract, oculi, and alimentary tract, it may also be important in the development and lipid metabolism of the adipose tissue [8].

Anatomical context of PLUNC

• Immunohistochemistry showed that PLUNC was expressed in human airway epithelium and submucosal glands [4].
• Parotid secretory protein (PSP) and palate-lung-nasal epithelium clone (PLUNC) are novel secretory proteins that are expressed in the oral cavity and upper airways [9].
• Here, we demonstrate the presence of multiple isoforms of palate lung nasal epithelial clone (PLUNC) in human nasal lavage fluid (NLF) [10].
• Among these genes, LPLUNC1 and SPLUNC1 were confirmed to be specifically expressed in nasopharyngeal epithelial tissue and the trachea [11].
• Lastly, we investigated whether epithelial differentiation and proinflammatory cytokines influence the expression of PLUNC in human nasal epithelial cells [12].

Associations of PLUNC with chemical compounds

• Although PLUNC is in the lipopolysaccharide (LPS)-binding protein (LBP) and bactericidal/permeability-increasing protein family of antibacterial host defense proteins, purified PLUNC failed to compete with LBP for the binding of LPS, whereas polymyxin B, a known inhibitor of LPS-LBP binding, did interfere with binding [4].
• PLUNC was poorly soluble in water (50 microg/ml) or in 50 mM NaCl but was more soluble in 75% ethanol (> 380 microg/ml) [4].

Regulatory relationships of PLUNC

• SPLUNC1 was differentially expressed in nasopharyngeal carcinoma [8].

Other interactions of PLUNC

• Moreover, three proteins that have not been previously identified in saliva, PLUNC, cystatin A, and cystatin B were identified [13].
• Association of PLUNC gene polymorphisms with susceptibility to nasopharyngeal carcinoma in a Chinese population [14].
• Consistent with the epithelial origin of this tissue, some of the identified proteins are epithelial markers (e.g. cytokeratins, palate lung and nasal epithelium clone protein (PLUNC), and squamous cell carcinoma antigen 1) [15].
• During allergy season, the levels of six sialylated isoforms of PLUNC (palate lung nasal epithelial clone) were lower in SAR patients than controls, as were the levels of six isoforms of von Ebner's gland protein (VEGP), including a previously undescribed form with N-linked glycosylation, and of cystatin S [16].

Analytical, diagnostic and therapeutic context of PLUNC

• Northern blot analysis showed that LUNX/PLUNC, BSP30 and VEMSGP are expressed in bovine salivary tissue and airways, and that they have non-identical patterns of expression in these tissues [17].
• We have identified two forms of the PLUNC protein in human nasal lavage fluid (NLF) using two-dimensional gel electrophoresis (2-DE) and MS [18].
• Reverse transcription-PCR (RT-PCR) of PLUNC was performed with mRNA from cultured human nasal epithelium cells treated with either interleukin-1beta or tumor necrosis factor-alpha [12].
• We have isolated a novel human lung-specific gene, LUNX (lung-specific X protein), by differential-display mRNA analysis [1].
• NASG gene expression was identified using aRNA by sqRT-PCR and showed that there was significant difference between the average value of case groups and that of control group (t = -5.275, df = 30, P < 0.001) [19].

References