Extraction of characteristic serum microRNAs and prediction of target genes in IgG4-related dacryoadenitis and sialadenitis

OBJECTIVES

To identify the specific microRNAs (miRNAs) in IgG4-related dacryoadenitis and sialadenitis (IgG4-DS) and predict the targeted genes.

METHODS

miRNAs in the serum of nine patients with IgG4-DS, three patients with primary Sjögren's syndrome, and three healthy controls were analysed using the human miRNA chip, and miRNAs that exhibited significant fluctuation in expression in IgG4-DS patients were extracted. The respective target genes were predicted using an existing database, and expression of the target genes was evaluated in actual submandibular gland tissues affected by IgG4-DS.

RESULTS

Serum miR-125a-3p and miR-125b-1-3p levels were elevated in IgG4-DS. Six candidate target genes (glypican 4, forkhead box C1, protein tyrosine phosphatase non-receptor type 3, hydroxycarboxylic acid receptor 1, major facilitator superfamily domain containing 11, and tumour-associated calcium signal transducer 2) were downregulated in the affected submandibular gland tissue.

CONCLUSION

Overexpression of miR-125a-3p and miR-125b-1-3p is a hallmark of IgG4-DS. These miRNAs appear to be involved in the pathogenesis of IgG4-DS.

Marginal Zone B (MZB) Cells: Comparison of the Initial Identification of Immune Activity Leading to Dacryoadenitis and Sialadenitis in Experimental Sjögren's Syndrome

Although multiple mouse strains have been advanced as models for Sjögren's syndrome (SS), which is a human systemic autoimmune disease characterized primarily as the loss of lacrimal and salivary gland functions, the C57BL/6.NOD-Aec1Aec2 recombinant inbred (RI) mouse derived from the NOD/ShiLtJ line is considered one of the more appropriate models exhibiting virtually all the characteristics of the human disease. This mouse model, as well as other mouse models of SS, have shown that B lymphocytes are essential for the onset and development of observed clinical manifestations. Recently, studies carried out in the C57BL/6.IL14α transgenic mouse have provided clear evidence that the marginal zone B (MZB) cell population is directly involved in the early pathological events initiating the development of the clinical SS disease, as well as late-stage lymphomagenesis resulting in B-cell lymphomas. Since MZB cells are difficult to study in vivo and in vitro, we carried out a series of ex vivo investigations that utilize temporal global RNA transcriptomic analyses to profile differentially expressed genes exhibiting temporal upregulation during the initial onset and subsequent development of pathophysiological events within the lacrimal and salivary gland tissues per se or associated with the leukocyte cell migrations into these glands. The initial transcriptomic analyses revealed that while the upregulated gene expression profiles obtained from lacrimal and salivary glands overlap, multiple genetic differences exist between the defined activated pathways. In the current study, we present a concept suggesting that the initial pathological events differ between the two glands, yet the subsequent upregulated TLR4/TLR3 signal transduction pathway that activates the type-1 interferon signature appears to be identical in the two glands and indicates an autoimmune response against dsRNA, possibly a virus. Here, we attempt to put these findings into perspective and determine how they can impact the design of future therapeutic protocols.

Toll-Like Receptor Signaling in the Pathogenesis of Chronic Dacryocystitis: Implication of c-FOS Transcription Factor and its Downstream Effector Chemokine Genes CCL2, CCL4, CXCL3, CXCR4 with a Shift of the M1/M2 Macrophage Phenotype

INTRODUCTION

TLRs are fundamental elements in the orchestration of the innate immune system. These receptors seem to be responsible for the inflammation and fibrosis in chronic dacryocystitis. The aim of the present study was to investigate the role of the toll-Like receptors (TLR2 and TLR4) signaling pathway and its downstream effector chemokine genes in the pathogenesis of chronic dacryocystitis.

METHODS

This study was conducted on 20 patients diagnosed with chronic dacryocystitis and underwent external dacryocystorhinostomy. Estimation of gene expression of TLR2, TLR4, CCL2, CCL4, CXCL3, CXCR4, and c-FOS genes in the lacrimal sac tissues was performed together with the assessment of the inflammatory markers TNFα, IL-1β, IFN-γ, and IL-22. Histopathological examination of the lacrimal sac walls using hematoxylin and eosin (H&E) stain, in addition to immunohistochemical staining of the CD68 and CD163 macrophage markers, was also performed.

RESULTS

Our results showed that TLR2, TLR4, and c-FOS gene expressions were significantly increased in the chronic dacryocystitis group with a subsequent increase in their downstream effector chemokine genes CCL2, CCL4, and CXCL3. This up-regulation of genes was accompanied by macrophage shift of polarization toward the M1 pro-inflammatory phenotype (increased CD68 and decreased CD163 expression), leading to increased levels of the pro-inflammatory cytokines (TNF- α, IL-1β and IFN-γ) and decreased anti-inflammatory marker IL-22 with chronic dacryocystitis.

CONCLUSION

It is essential to fine-tune TLR activation through emerging therapeutic approaches. Targeting TLR signaling at the level of receptors or downstream adaptor molecules represents a new challenge for treating chronic dacryocystitis.

Tear miRNAs Identified in a Murine Model of Sjögren’s Syndrome as Potential Diagnostic Biomarkers and Indicators of Disease Mechanism

Objective

The tear miRNAome of the male NOD mouse, a model of ocular symptoms of Sjögren’s syndrome (SS), was analyzed to identify unique miRNAs.

Methods

Male NOD mice, aged 12-14 weeks, were used to identify tear miRNAs associated with development of autoimmune dacryoadenitis. Age- and sex-matched male BALB/c mice served as healthy controls while age-matched female NOD mice that do not develop the autoimmune dacryoadenitis characteristic of SS were used as additional controls. Total RNA was isolated from stimulated tears pooled from 5 mice per sample and tear miRNAs were sequenced and analyzed. Putative miRNA hits were validated in additional mouse cohorts as well as in tears of SS patients versus patients with another form of dry eye disease, meibomian gland disease (MGD) using qRT-PCR. The pathways influenced by the validated hits were identified using Ingenuity Pathway Analysis.

Results

In comparison to tears from both healthy (male BALB/c) and additional control (female NOD) mice, initial analy1sis identified 7 upregulated and 7 downregulated miRNAs in male NOD mouse tears. Of these, 8 were validated by RT-qPCR in tears from additional mouse cohorts. miRNAs previously implicated in SS pathology included mmu-miR-146a/b-5p, which were significantly downregulated, as well as mmu-miR-150-5p and mmu-miR-181a-5p, which were upregulated in male NOD mouse tears. All other validated hits including the upregulated miR-181b-5p and mmu-miR-203-3p, as well as the downregulated mmu-miR-322-5p and mmu-miR-503-5p, represent novel putative indicators of autoimmune dacryoadenitis in SS. When compared to tears from patients with MGD, miRNAs hsa-miR-203a-3p, hsa-miR-181a-5p and hsa-miR-181b-5p were also significantly increased in tears of SS patients.

Conclusions

A panel of differentially expressed miRNAs were identified in tears of male NOD mice, with some preliminary validation in SS patients, including some never previously linked to SS. These may have potential utility as indicators of ocular symptoms of SS; evaluation of the pathways influenced by these dysregulated miRNAs may also provide further insights into SS pathogenesis.

An autoimmune response to odorant binding protein 1a is associated with dry eye in the Aire-deficient mouse

Sjögren's Syndrome (SS) is a human autoimmune disease characterized by immune-mediated destruction of the lacrimal and salivary glands. In this study, we show that the Aire-deficient mouse represents a new tool to investigate autoimmune dacryoadenitis and keratoconjunctivitis sicca, features of SS. Previous work in the Aire-deficient mouse suggested a role for alpha-fodrin, a ubiquitous Ag, in the disease process. Using an unbiased biochemical approach, however, we have identified a novel lacrimal gland autoantigen, odorant binding protein 1a, targeted by the autoimmune response. This novel autoantigen is expressed in the thymus in an Aire-dependent manner. The results from our study suggest that defects in central tolerance may contribute to SS and provide a new and clinically relevant model to investigate the pathogenic mechanisms in lacrimal gland autoimmunity and associated ocular surface sequelae.

Lacrimal gland inflammation is responsible for ocular pathology in TGF-beta 1 null mice

Mice homozygous for a nonfunctional transforming growth factor-beta 1 gene develop rampant inflammation in vital organs that contributes to a shortened life span. The presence of circulating anti-nuclear anti-bodies, immune deposits in tissues, leukocyte infiltration, and increased major histocompatibility complex antigen expression resembles an autoimmune-like syndrome. One of the overt symptoms that appears in these mice lacking transforming growth factor-beta 1 is the development of dry crusty eyes that close persistently as their health declines. Histologically, the eyes appear normal with little or no inflammation. However, inflammatory lesions, predominantly lymphocytic, develop in the lacrimal glands, disrupting their structure and function and severely limiting their ability to generate tears. This histopathology and aberrant function mimic that of Sjögren's syndrome, a human autoimmune disease characterized by dry eyes and dry mouth. Impeding the leukocyte infiltration into the glands with synthetic fibronectin peptides, which block adhesion, not only prevents the inflammatory pathology but also prevents the persistent eye closure characteristic of these mice.

Dacryocystitis associated with osteopoikilosis

We report five members of a family with dacryocystitis associated with osteopoikilosis. The inheritance is autosomal dominant. Review of the literature revealed no other report of this kind of association. Osteopoikilosis must not be considered as a coincidental radiographic finding but as part of a systemic disorder.

Chronic bilateral dacryo-adenitis in identical twins: a possible incomplete form of Sjögren syndrome

We report an unusual case of chronic bilateral dacryo-adenitis in 10-year-old identical twin sisters. Both girls presented with bilateral lacrimal gland enlargement and developed moderate xerophthalmia and keratitis. Both the lacrimal and minor salivary gland biopsies showed a non-granulomatous inflammatory infiltration of mono-nuclear cells. All granulomatous diseases and neoplasms could therefore be ruled out and only Sjögren syndrome and very few other forms of chronic dacryo-adenitis remained as possible diagnoses. Both patients and their parents were evaluated for auto-antibodies. Very low titres of smooth muscle antibodies were found in one, antinuclear antibodies in two and anti-dsDNA antibodies in all four members of the family. Even though the titres of antinuclear and anti-dsDNA antibodies increased in one of the sisters, both patients did not develop any sign or symptom of a systemic connective tissue disease. During the 6 years' follow up, both patients showed persistent tarsal gland enlargement but no other symptoms apart from a moderate xerophthalmia and occasional mild keratitis.

The EEC syndrome and its ocular manifestations

The EEC syndrome (ectrodactyly or lobster-claw deformity, ectodermal dysplasia, and cleft lip and palate) is a rare disorder with autosomal dominant inheritance, variable expression, and in some families lack of penetrance. We present the findings in five cases with emphasis on the ocular findings. Lacrimal surgery was performed on three patients with good results in each case. We also report the occurrence of spontaneous corneal perforation in two cases, a complication not previously recognised. The ophthalmic care of these patients must be pursued long-term, as progressive visual impairment may be the most disabling feature of the syndrome.

Lacrimal gland enlargement in familial sarcoidosis

Familial sarcoidosis is rare. It is unusual for lacrimal gland enlargement to be the initial manifestation of sarcoidosis. Two sisters are described with lacrimal gland enlargement as the initial manifestation of sarcoidosis. Gallium-67 scan was a useful adjunct to lacrimal biopsy in sarcoidosis. Sarcoid dacryoadenitis responded dramatically to a short term course of low dose prednisone.