PURPOSE Lacritin is a novel human tear glycoprotein that promotes basal tear peroxidase secretion by rat lacrimal acinar cells in vitro. This study investigates whether lacritin is prosecretory when added topically to the ocular surface of normal living rabbits, and if so, what is its efficacy and tolerability versus cyclosporine and artificial tears. METHODS Purified recombinant human lacrit...

Multiple extracellular factors are hypothesized to promote the differentiation of unstimulated and/or stimulated secretory pathways in exocrine secretory cells, but the identity of differentiation factors, particularly those organ-specific, remain largely unknown. Here, we report on the identification of a novel secreted glycoprotein, lacritin, that enhances exocrine secretion in overnight cult...

Renewal of nongermative epithelia is poorly understood. The novel mitogen "lacritin" is apically secreted by several nongermative epithelia. We tested 17 different cell types and discovered that lacritin is preferentially mitogenic or prosecretory for those types that normally contact lacritin during its glandular outward flow. Mitogenesis is dependent on lacritin's C-terminal domain, which can...

Lacritin is a 12.3 kDa secreted tear protein in human (accession Q9GZZ8 [Genpept; UniProt; Sanghi et al., 2001]) and non-human primates. It consists of 119 aa after removal of the signal peptide (SP; Fig. 1) and has a predicted isoelectric point (pI ) of 5. Predicted values for secreted lacritin in non-human primates include the following: 12.2 kDa and pI of 5 (Chlorocebus aethiops), 12.3 kDa a...

purpose : the main ocular manifestation of rheumatoid arthritis is dry eye. lacritin is a secreted glycoprotein of tear and when applied topically in rabbits, it increased the volume of basal tear secretion. so the aim of this study was to compare lacritin level in rheumatoid arthritis (ra) and control group. methods : this cross-sectional study was done on 40 patients with ra and 48 healthy su...

Tear proteins are potential biomarkers, drug targets, and even biotherapeutics. As a biotherapeutic, a recombinant tear protein might physiologically rescue the ocular surface when a deficiency is detected. Such a strategy pays more attention to the natural prosecretory and protective properties of the tear film and seeks to alleviate symptoms by addressing cause, rather than the current pallia...

Cell surface heparan sulfate (HS) proteoglycans shape organogenesis and homeostasis by capture and release of morphogens through mechanisms largely thought to exclude the core protein domain. Nevertheless, heparanase deglycanation of the N-terminal HS-rich domain of syndecan-1 (SDC1), but not SDC2 or -4, is a prerequisite for binding of the prosecretory mitogen lacritin (Ma, P., Beck, S. L., Ra...

The lacrimal functional unit (LFU) is defined by the 2007 International Dry Eye WorkShop as 'an integrated system comprising the lacrimal glands, ocular surface (cornea, conjunctiva and meibomian glands) and lids, and the sensory and motor nerves that connect them'. The LFU maintains a healthy ocular surface primarily through a properly functioning tear film that provides protection, lubricatio...

Antimicrobial peptides are important as the first line of innate defense, through their tendency to disrupt bacterial membranes or intracellular pathways and potentially as the next generation of antibiotics. How they protect wet epithelia is not entirely clear, with most individually inactive under physiological conditions and many preferentially targeting Gram-positive bacteria. Tears coverin...