MUC19 expression in human ocular surface and lacrimal gland and its alteration in Sjögren syndrome patients

Yu, Dongfang; Chen, Y.; Han, Jae-Il; Zhang, H.; Chen, X.P.; Zou, Wei; Liu, Liang; Xu, Chao; Liu, Z.G.

doi:10.1016/j.exer.2007.11.013

Cited by 69 publications

(46 citation statements)

References 22 publications

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“…Yu et al (2008) described the coexpression of MUC19 and MUC5AC in cells of the conjunctival epithelia and lacrimal glands of man, whereas MUC19, but not MUC5AC, is expressed in the corneal epithelium. We do not find Muc19 expression in conjunctiva or in lacrimal and Harderian glands, suggesting species differences and possibly a broader tissue distribution of MUC19 in man than in mice.…”

Section: Discussionmentioning

confidence: 99%

Tissue Distribution of Murine Muc19/Smgc Gene Products

Das

Cash

Hand

et al. 2009

J Histochem Cytochem.

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(ARH) S U M M A R Y The recently identified gene Muc19/Smgc encodes two diverse splice variants, Smgc (submandibular gland protein C) and Muc19 (mucin 19). Muc19 is a member of the large gel-forming mucin family and is an exocrine product of sublingual mucous salivary glands in mice. SMGC is a transiently expressed secretion product of developing rodent submandibular and sublingual glands. Little is known about the expression of Muc19/Smgc gene products in other murine salivary and non-salivary tissues containing the mucous cell phenotype. Muc19 expression was therefore initially assessed by RT-PCR and immunohistochemistry. As a complementary approach, we developed a knockin mouse model, Muc19-EGFP, in which mice express a fusion protein containing the first 69 residues of Muc19 followed by enhanced green fluorescent protein (EGFP) as a marker of Muc19 expression. Results from both approaches are consistent, with preferential Muc19 expression in salivary major and minor mucous glands as well as submucosal glands of the tracheolarynx and bulbourethral glands. Evidence also indicates that individual mucous cells of minor salivary and bulbourethral glands produce another gel-forming mucin in addition to Muc19. We further find tissue expression of full-length Smgc transcripts, which encode for SMGC, and are restricted to neonatal tracheolarynx and all salivary tissues. (J Histochem Cytochem 58:141-156, 2010)

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Section: Discussionmentioning

confidence: 99%

Tissue Distribution of Murine Muc19/Smgc Gene Products

Das

Cash

Hand

et al. 2009

J Histochem Cytochem.

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“…In this unit, the Meibomian glands provide the outermost hydrophobic lipid layer that slows tear film evaporation (6,30). Secretions from the cornea, conjunctiva, and lacrimal gland may all contribute to the aqueous/mucous layer, which is composed of water, mucins, ions, amino acids, growth factors, neurotransmitters, and other proteins (17,52). The neural input to these tissues regulates secretion rates (9).…”

mentioning

confidence: 99%

Regional differences in rat conjunctival ion transport activities

Thelin

Rogers

et al. 2012

American Journal of Physiology-Cell Physiology

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Active ion transport and coupled osmotic water flow are essential to maintain ocular surface health. We investigated regional differences in the ion transport activities of the rat conjunctivas and compared these activities with those of cornea and lacrimal gland. The epithelial sodium channel (ENaC), sodium/glucose cotransporter 1 (Slc5a1), transmembrane protein 16 (Tmem16a, b, f, and g), cystic fibrosis transmembrane conductance regulator (Cftr), and mucin (Muc4, 5ac, and 5b) mRNA expression was characterized by RT-PCR. ENaC proteins were measured by Western blot. Prespecified regions (palpebral, fornical, and bulbar) of freshly isolated conjunctival tissues and cell cultures were studied electrophysiologically with Ussing chambers. The transepithelial electrical potential difference (PD) of the ocular surface was also measured in vivo. The effect of amiloride and UTP on the tear volume was evaluated in lacrimal gland excised rats. All selected genes were detected but with different expression patterns. We detected αENaC protein in all tissues, βENaC in palpebral and fornical conjunctiva, and γENaC in all tissues except lacrimal glands. Electrophysiological studies of conjunctival tissues and cell cultures identified functional ENaC, SLC5A1, CFTR, and TMEM16. Fornical conjunctiva exhibited the most active ion transport under basal conditions amongst conjunctival regions. PD measurements confirmed functional ENaC-mediated Na(+) transport on the ocular surface. Amiloride and UTP increased tear volume in lacrimal gland excised rats. This study demonstrated that the different regions of the conjunctiva exhibited a spectrum of ion transport activities. Understanding the specific functions of distinct regions of the conjunctiva may foster a better understanding of the physiology maintaining hydration of the ocular surface.

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“…The cornea and conjunctiva are stratified, nonkeratinizing epithelium and these cells along with the lacrimal gland produce the aqueous layer, containing proteins, electrolytes, water and soluble mucins, for example, MUC7 which has antimicrobial activity and is expressed by the conjunctiva and the lacrimal glands [73]. This aqueous has also been detected in the apical cells of the cornea [73,74]. This gel layer is up to 0.5 µm thick.…”

Section: The Eye Mucus Barriermentioning

confidence: 93%

The Properties of the Mucus Barrier, a Unique Gel–How Can Nanoparticles Cross It?

2016

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The key criterion for a nanoparticle drug-delivery system is the ability to produce substantial bioavailability without damaging the physiological protective mechanisms. The main area for drug delivery is the aerodigestive tract. All epithelial surfaces have a membrane-bound layer and in the lung this layer is surmounted by a gel layer. In the gastrointestinal tract the membrane-bound mucin layer is covered by a mucus bilayer. The pore sizes of mucus gels are around 100 to 200 nm. Consequently, only nanoparticles in this size range could potentially penetrate without modification of these layers. To study nanoparticle permeation with results that pertain to in vivo conditions, native mucus mucin preparations must be used. Strategies to increase pores in mucus gels are discussed herein.

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MUC19 expression in human ocular surface and lacrimal gland and its alteration in Sjögren syndrome patients

Cited by 69 publications

References 22 publications

Tissue Distribution of Murine Muc19/Smgc Gene Products

Tissue Distribution of Murine Muc19/Smgc Gene Products

Regional differences in rat conjunctival ion transport activities

The Properties of the Mucus Barrier, a Unique Gel–How Can Nanoparticles Cross It?

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