Background

The polymeric Immunoglobulin Receptor (pIgR), initially known as "Secretory Component" (SC) in the early literature, is expressed on mucosal epithelial cells where it binds and transports polymeric IgM and dimeric IgA across the epithelial barrier and out to the mucosal secretions [1].

Disease relevance of Pigr

• Contribution of polymeric immunoglobulin receptor to regulation of intestinal inflammation in dextran sulfate sodium-induced colitis [2].
• Additionally, colonic tissues from the pIgR(-/-) mice exhibited progressively and significantly greater degrees of mucosal edema, ulceration, crypt abscesses and macrophage infiltration when compared to similarly treated IgA(-/-) mice and wild-type animals [2].
• Mesangial IgA in IgA nephropathy are dimers with a J chain but no poly-Ig receptor [3].

High impact information on Pigr

• Absence of epithelial immunoglobulin A transport, with increased mucosal leakiness, in polymeric immunoglobulin receptor/secretory component-deficient mice [4].
• The polymeric immunoglobulin receptor, a transmembrane protein, is made by a variety of polarized epithelial cells [5].
• Functional expression of the polymeric immunoglobulin receptor from cloned cDNA in fibroblasts [5].
• Accumulation of intestinal intraepithelial lymphocytes in association with lack of polymeric immunoglobulin receptor [6].
• Molecular cloning of a novel member of the immunoglobulin gene superfamily homologous to the polymeric immunoglobulin receptor [7].
• Northern blot analysis of salivary gland RNA revealed that these vitamin A-deficient mice also had greater levels of mRNA of the polymeric immunoglobulin receptor (pIgR), which transports IgA across mucosal surfaces (plgR: beta-actin mRNA ratio = 7.8 +/- 0.8), than did pair-fed control mice (3.7 +/- 0.4, P = 0.0001) [8].

Biological context of Pigr

• The pIgR transgenic line 3644, having the highest pIgR transgene expression, had a markedly altered milk composition compared to non-transgenic mice [9].
• During this process, the 110 kDa form of pIgR was converted into a 120 kDa form by glycosylation [10].
• Collectively, the pIgR and/or the secretory component are important for the maintenance of epithelial integrity and mucosal homeostasis in the colonic epithelium [2].
• The tissue distribution of mouse polymeric immunoglobulin receptor (pIgR) has been demonstrated [11].
• We previously identified a novel Fc receptor for IgA and IgM, designated Fcalpha/mu receptor (Fcalpha/muR), whose gene is closely located at the polymeric immunoglobulin receptor (poly-IgR), also a receptor for IgA and IgM, in the Fc receptor gene cluster on the chromosome 1 [12].

Anatomical context of Pigr

• PCR amplification of liver progenitor cell chromosomal (rat and mouse Pigr, rat INS1, mouse INS2) and mitochondrial (rat and mouse COX1) genes revealed only mouse sequences [13].
• The pIgR is consumed during the transcytosis of dIgA and is cleaved at the apical side of the epithelial cells, regardless of the binding to its ligand (dIgA), to form secretory component (SC) [14].
• Four transgenic lines were made, expressing the pIgR construct at RNA and protein level only in their mammary glands [14].
• A high level of poly-Ig receptor or Thy-1 mRNA accumulation was observed in MDCK cells in response to dexamethasone with a parallel ten- to 200-fold increase in protein synthesis depending on the recombinant protein and the transfected cell clone [15].
• Taken together, our findings suggest that dietary FOS increases the intestinal IgA response and pIgR expression in the small intestine as well as the colon in infant mice [16].

Associations of Pigr with chemical compounds

• Moreover, tunicamycin treatment revealed the core form of pIgR had a molecular mass of approximately 100 kDa [10].
• It was found that dextran sulfate sodium-treated pIgR(-/-) mice displayed greater loss of bodyweight and had severe clinical illness compared to similarly treated IgA(-/-) mice and wild-type animals [2].
• We found a repetition of CA dinucleotides on the second intron of mouse polymeric immunoglobulin receptor (PIgR) gene [17].

Analytical, diagnostic and therapeutic context of Pigr

• Western blotting and metabolic labeling experiments followed by immunoprecipitation with an anti-mouse secretory component (SC) Ab demonstrated the existence of a 110 kDa immature form of pIgR [10].
• Using RT-PCR we also show that mRNA for the polymeric immunoglobulin receptor (PIgR), which transports IgA across mucosal epithelia, is expressed only in the prostate but not in other regions of the male reproductive ducts upstream of the prostate [18].

References