Idiopathic pulmonary fibrosis (IPF) is an age-related and progressive interstitial lung disease, with a life expectancy of 3-5 years after diagnosis. Accumulating evidence indicates that genetic factors, both common and rare variants, contribute significantly to the pathogenesis of IPF. Genome-wide association studies have identified several common variants linked to IPF risk, for example, the most widely replicated variant rs35705950 located in the promoter region of the MUC5B
gene.,, Next generation sequencing (NGS) technologies have facilitated the identification of rare genetic variants.
Based on the structure and function of a molecule, mucin is subdivided into 3 categories: membrane-bound mucins (MUC1, MUC3 MUC4, MUC12, MUC16, MUC17), gel-forming (secreted) mucins (MUC2, MUC5AC, MUC5B
, MUC6, MUC19), and soluble mucin (MUC7).
The primary antibodies used in this study were rabbit antiSP-C (1:1000, Merck Millipore, USA), rabbit anti-AQP-5 (1:1000, Abcam, USA), mouse anti-thyroid transcription factor-1 (TTF-1; 1:1000, Thermo Fisher Scientific, UK), rabbit anti-zonula occludens-1 (ZO-1; 1:1000, Zymed Lab Inc., USA), rabbit anti-Mucin 5B (MUC5B
; 1:1000, Santa Cruz Biotech, USA) and rabbit anti-[beta]-actin (1:1000, Santa Cruz Biotech).
Salivary glycoconjugates such as mucins (MUC1, MUC4, MUC5B
, MUC7, and MUC19), proline-rich glycoproteins (PRGs), and kallikrein may also ensure the appropriate hydration of the oral mucosa and maintain the proper pH of the stimulated and nonstimulated saliva [8, 9].
Williamson et al., "Expression of MUC2, MUC5AC, MUC5B
, and MUC6 mucins in colorectal cancers and their association with the CpG island methylator phenotype," Modern Pathology, vol.
The two main secreted airway mucins are MUC5AC and MUC5B
[38, 40]; the latter but not MUC5AC seems to be required for airway defence against bacteria .
DAMP TLR Refs (i) Biglycan and decorin are degraded TLR2 and by saliva from NOD.B10 mice TLR4  (ii) Versican is increased in SGEC lines TLR2/6  from SS patients heterodimer (i) Fibronectin is dysregulated in salivary  tissue from SS mice and upregulated in  saliva from SS patients  (ii) Calprotectin (S100A8/A9) levels are TLR4  elevated in sera, salivary tissue, and  saliva of pSS patients  (iii) MUC5B
and MUC7 are mislocalized  in the ECM of pSS patients  (i) Long interspersed nuclear element 1  (LINE-1) is increased in MSG tissue TLR 7/8  from SS patients
Higher levels of salivary MUC5B
and MUC7 in individuals with gastric diseases who harbor Helicobacter pylori .
The expression of MUC5AC and MUC5B
mucin genes in the mucosa of chronic rhinosinusitis and nasal polyposis.
Estrogen has been demonstrated to upregulate the MUC5B
gene, a major mucin in the human airway .
The genes that can be evaluated further are Th2-related genes (interleukin 4 (IL-4), interleukin-5 (IL-5), and interleukin-13 (IL-13)), transforming growth factor-[beta] (TGF-[beta]), mucin (MUC) genes (MUC5AC, MUC5B
), Signal Transducer and Activator of Transcription 6 (STAT6), and forkhead box A2 (FOXA2) which are closely involved in asthma onset and progression.