Labial gland-derived mesenchymal stem cells and their exosomes ameliorate murine Sjögren's syndrome by modulating the balance of Treg and Th17 cells

Background Sjögren's syndrome (SS) is a chronic, systemic autoimmune disorder characterized by sicca syndrome and/or systemic manifestations. The disease severely affects the health and life of patients, and the treatment of SS has always been a clinical challenge and essentially palliative. Mesenchymal stem cells (MSCs) have been reported to exert immunomodulatory effects and as a potential novel therapeutic strategy for SS. Labial gland-derived MSCs (LGMSCs) are a population of resident stem cells in the labial gland, first isolated by our group. Exosomes released by MSCs contain a large variety of bioactive molecules and considered to function as an extension of MSCs. Methods LGMSCs were isolated from patients who were needed surgery to remove the lip mucocele and LGMSCs derived exosomes (LGMSC-Exos) were isolated by ultracentrifugation. The non-obese diabetic (NOD) mice were treated with LGMSCs or LGMSC-Exos by tail vein injection. The saliva flow rate of mice was determined and salivary glands were dissected and stained with hematoxylin and eosin. In vitro, peripheral blood mononuclear cells (PBMCs) from SS patients were cocultured with LGMSCs or LGMSC-Exos. Percentage of T helper 17 (Th17) cells and regulatory T (Treg) cells were determined by flow cytometry. The serum levels of cytokines in NOD mice and in the supernatant of the co-culture system by ELISA. Results Treatment with LGMSCs or LGMSC-Exos reduced inflammatory infiltration in the salivary glands, and restored salivary gland secretory function in NOD mice. Importantly, LGMSCs or LGMSC-Exos were demonstrated to inhibit the differentiation of Th17 cells but promote the induction of Treg cells in NOD mice and PBMCs from SS patients in vitro, accompanied by reduced interleukin 17 (IL-17), interferon gamma, and IL-6 levels and enhanced transforming growth factor beta and IL-10 secretion by T cells. Conclusions LGMSCs are potential candidates for MSCs-based therapy and LGMSC-Exos might be utilized for establishing a new cell-free therapy against SS.

A Gland of Many Uses: A Diversity of Compounds In The Labial Glands of The Bumble Bee Bombus Impatiens Suggests Multiple Signaling Functions

Communication in social insect colonies depends on signals accurately reflecting the identity and physiological state of the individuals. Such information is coded by the products of multiple exocrine glands, and the resulting blends reflect the species, sex, caste, age, task, reproductive status, and health of an individual, and may also contain caste-specific pheromones regulating the behavior and physiology of other individuals. Here we examined the composition of labial gland secretions in females of the bumble bee Bombus impatiens, of different castes, social condition, age, mating status, and ovarian activation. We show that active queens, gynes, and workers each produce caste-specific compounds that may serve different communicative functions. The composition and amounts of wax esters, mostly octyl esters produced by active queens, differed significantly between castes, mating, and social conditions, suggesting a social signaling role. Farnesyl esters were predominant in gynes and peaked at optimal mating age (6-10 days), suggesting their possible roles as sex pheromone components. Reproductive status of females and age across castes was reflected by the ratio between short- and long-chain hydrocarbons, suggesting that these compounds may serve as fertility signals. Our findings overall suggest that the labial gland composition in B. impatiens reflects different facets of female bee physiology. While further bioassays are required to determine the function of these compounds, they are likely to have an important role in the communication between individuals and to the cohesion of the social structure.

EP27 Sjögren’s or not: an anxious diagnosis

Case report - Introduction Sjögren’s syndrome is a chronic, autoimmune condition usually characterised by reduced function of exocrine glands (mainly lacrimal and salivary) resulting in sicca symptoms. Affected patients may also have extra-glandular features including arthritis, neuropathy, and interstitial nephritis. This is a case of possible Sjögren’s syndrome without classical features like positive serology or histology. This makes the patient feel anxious about his overall health. Diagnostic criteria have been debated over the years and whilst some clinical features may be suggestive, more objective evidence can help guide discussions on long term management and prognosis to allay anxiety. Case report - Case description A 63-year-old Asian gentleman has had 6 years of intermittent cervical lymphadenopathy, dry eye and mouth symptoms without weight loss or respiratory complaints. His background includes ulcerative colitis (relatively stable), angina, hypertension, degenerative back pain (confirmed on MRI), dental extraction and diabetes. Interval FNA sampling and excision biopsy of a prominent chain of right cervical nodes on separate occasions showed “reactive changes” with negative Mycobacterium TB screening (serology and lymph nodes). Blood tests show a normal CRP (<5 mg/L), ESR 36 mm/h, raised polyclonal IgG 28.6 g/L (IgG subclass 1, 20.40 g/L, subclass 2, 9.36g/L, subclass 3, 0.954g/L, subclass 4, 9.430g/L) , normal complement and negative results for ANA, HLA B27, Anti CCP and ANCA. Bilateral submandibular gland ultrasound showed hyperechoic lesions consistent with either chronic sialadenitis or Sjögren’s. FNA sampling of an intra-parotid lesion showed a “reactive” lymph node. A left lower lobe 5mm calcified granuloma seen on plain film was confirmed on CT chest imaging along with mild inflammatory changes (lingual area) and multiple soft tissue density nodules up to 1cm in the anterior mediastinum. Initially thought thymoma related, later it was agreed these were benign lymph nodes after noting bilateral, sub-centimetre axillary and pre-tracheal nodes of similar appearance. Following annual surveillance, a recent scan shows persistence of the lingular nodular focus, mediastinal lymphadenopathy and a 4mm ground glass nodule not thought suitable for PET CT or CT guided sampling. The previously seen parotid lymph node appears reduced and scattered low grade nodes are seen in the neck, chest, and porta hepatis. Ophthalmologists note a poor-quality tear film with an equivocal Schirmer’s test. He has been treated for blepharitis and diagnosed with macular oedema. He was due to have a labial gland (lip) biopsy but later declined the procedure. Case report - Discussion Sjögren’s syndrome has a female preponderance and is usually associated with sicca symptoms, a positive Schirmer’s test and autoantibodies (anti-Ro and anti-La). Extra-glandular features may exist, and secondary Sjögren’s features are seen in other autoimmune conditions. Various diagnostic criteria have been proposed using clinical, serological, and/or histological features. This patient has sicca symptoms, lymphadenopathy, and imaging findings suggestive of Sjögren’s. Though not routinely used, salivary gland imaging features include enlarged, hyperechoic lesions and later stage multi-cystic or reticular patterns within atrophic glands. Due to ethnicity, negative autoantibodies and imaging, the differential of tuberculosis (TB) was excluded. A labial gland biopsy was suggested as it may be a potentially sensitive and specific Sjögren’s biomarker. Presence of multiple, periductal, lymphocytic foci can help exclude alternative diagnoses like sarcoidosis, amyloidosis, or lymphoma. However, the patient declined the procedure due to concerns about possible post procedure hypersensitivity. This patient has mild fatigue and non-specific arthralgia but not typical of fibromyalgia which is known to mimic Sjögren’s. Reassuringly, he remains well but anxious about lymphadenopathy which he feels is unrelated to his mild ulcerative colitis managed with prednisolone enemas. In the absence of arthritis or significant organ involvement, he has only been given symptomatic treatment (e.g. eye drops). In Sjogren’s, any increased or persistent lymphadenopathy calls for further investigation. Other predictors include low complement and cryoglobulins which are absent in this patient. This case may add to the evidence of co-existence of secondary Sjögren’s or Sjogren’s like syndrome with IBD which seems uncommon and in other cases, appears to be in conjunction with immunosuppressive treatment and autoantibodies. Duration of follow up required remains uncertain and whilst the patient requires little ongoing monitoring, health anxieties can precipitate frequent contact. Case report - Key learning points Sjögren’s syndrome (SS) can be variable in presentation but in most cases is mildUnlike other autoimmune disorders, in SS there is a lack of standardised criteria for diagnosis and classificationSome features can be non- specific and like features of fibromyalgia and sarcoidosisIn unclear cases, like this, objective markers like serology or histology (labial gland biopsy) may be more helpfulIn lymphadenopathy, depending on size and appearance, further investigations require multidisciplinary discussion to check if regular imaging is more appropriate compared to invasive tests. The frequency of imaging and potential radiation exposure needs careful consideration.In this case the patient is unwilling to undergo further invasive tests like a biopsy and the lymphadenopathy seen on imaging is thought relatively stable and not amendable to sampling.The ideal duration of follow up and need for ongoing investigations in this patient remains unclear – advice on monitoring and outcome of similar cases may help guide patient management and reduce anxiety

A Novel Head Capsule Labial Gland Lobe in the Black Field Cricket (Orthoptera: Gryllidae)

We describe a pair of labial gland lobes on either side of the retrocerebral complex in the head of the Australian black field cricket, Teleogryllus commodus Walker. As the retrocerebral complex includes the corpora cardiaca and corpora allata, hormones secreted by these glands can be absorbed by these lobes. These lobes of the labial gland are connected to the thoracic lobes via a relatively long duct that enters the main duct draining the thoracic lobes. Measurement of the flow rate of dye from head to thorax in the ducts is rapid, suggesting that these glands may serve as a transport system into the thoracic region. Both serotonin and adipokinetic hormone are shown to be present in the lobes near the retrocerebral complex and the ducts of the thoracic lobes, but whether this connection between the head and thorax acts as a hormone transporter is still unclear.

OP0095 A DECISION MODEL OF LABIAL GLAND BIOPSY BASED ON B-MODE ULTRASONOGRAPHY WITH SHEAR-WAVE ELASTOGRAPHY IN PATIENTS WITH SUSPECTED SJÖGREN’S SYNDROME

Background:Focal lymphocytic sialadenitis defined as focus score (FS) ≥1 on labial gland (LG) biopsy plays an integral role in various classification criteria of Sjögren’s syndrome (SS). However, suspected patients often hesitate to receive a biopsy; and rheumatologists hope a decision for biopsy based on a high predicted incidence of FS≥1, or against biopsy based on an absolutely low predicted incidence.Objectives:To build a decision model of LG biopsy based on B-mode ultrasonography (US) with shear-wave elastography (SWE) in patients with suspected SS.Methods:Patients who had at least one symptom of oral dryness (based on AECG questions) or had anti-SSA positive were recruited and signed a written informed consent. Bilateral parotid (PG) and submandibular glands (SMG) were examined with B-mode US which graded the echostructure of each gland on a scoring system scaled 0 to 4 (US score), and SWE which described the elasticity of glands. Then LG biopsy was performed.Results:(1)Ninety-one patients whose mean age was 43±15 years were enrolled and 93% of them were female. Anti-SSA was detected in 77 patients (85%) and 28 patients (31%) showed unstimulated whole saliva flow rate (USFR)≤0.1mL/mim. There were 57 patients (63%) showing FS≥1 on LG biopsy. Sixty-three patients (69%) were classified as primary SS, 10 patients (10%) were secondary SS, 18 patients (20%) were uCTD and one patient was RA without SS.(2)US scores were equal between PG and SMG in 59 patients (65%), while the rest patients showed different US scores between two glands: 7 patients (8%) showed higher US scores in PG and 25 patients (27%) showed higher scores in SMG. In each pair of glands US scores were equal. SWE values in PG or SMG of US score 1, 2 or 3 were significantly higher than those of US score 0, while SWE values in glands of US score 4 became declined and showed no significant difference from those with US score 0 (Figure 1A).(3)Heatmap showed US scores in either major salivary gland of patients with FS≥1 on LG biopsy were significantly higher than those with FS<1 (all p<0.001, Figure 1B). ROC curve showed a total US score (including bilateral PG and SMG) ≥9 and a total SWE value (including bilateral PG and SMG)≥30 could significantly recognize patients with FS≥1, respectively with specificity of 100% and 93% (Figure 1C). In this cohort, among 51 patients with a total US score ≥9 and/or a total SWE value≥30, 49 patients (96%) showed FS≥1 on LG biopsy; while two outliers showed total US scores were both 8 although combined SWE values≥30. Other 29 patients showed total US scores≤6 with total SWE values <30 and only one patient (3%) showed FS≥1 on LG biopsy. The remaining 11 patients showed total US scores were 8 with total SWE values <30 and 64% of them (n=7) showed FS≥1.Conclusion:A preliminary decision model of LG biopsy based on B-mode US with SWE in patients with suspected SS were built in Table 1. For example, rheumatologists should reassess the need for biopsy if the incidence of FS≥1 would be <5%. Another cohort of patients with suspected SS is needed for further validation.Table 1.A preliminary decision model of LG biopsy based on B-mode US with SWE in patients with suspected SSAlgorithm*Comments on the decision of LG biopsyA total US score≥9 and/or a total SWE≥30The specificity of FS≥1 on biopsy is >93%. Biopsy is recommended. In some special cases (e.g. contraindicated to biopsy), this item is a potential alternative to LG biopsy.A total US score 7~8 with a total SWE <30It is hard to predict the result of FS, so biopsy is strongly recommended.A total US score≤6 with a total SWE <30The incidence of FS≥1 would be <5%. Rheumatologists should reassess the need for biopsy.References:NoneDisclosure of Interests:None declared

Sexual attraction: a review of bumblebee male pheromones

Males of many bumblebee species exhibit a conspicuous pre-mating behavior with two distinct behavioral components: scent marking and patrol flying. The marking pheromone is produced by the cephalic part of the labial gland (CLG). As far as is known, the CLG secretion is species specific, and it usually consists of two types of compounds: (i) straight-chain aliphatic alcohols, aldehydes or esters, and (ii) acyclic mono-, sesqui- and diterpenes (alcohols or acetates). Here, we summarize data from the literature reporting chemical composition of the CLG secretions of more than 80 bumblebee species. Similarities and differences within and between subgenera are discussed in the context of biosynthetic pathways and evolution.

Lyonet’s gland of the tomato fruitworm, Helicoverpa zea (Lepidoptera: Noctuidae)

The Lyonet’s gland is a widespread accessory labial gland in Lepidoptera. Although its function is ambiguous, the Lyonet’s gland arguably plays an important role in silk production. Our knowledge of the Lyonet’s gland in heliothine species is extremely limited; it is reportedly missing fromHelicoverpaarmigeraandHeliothisvirescens, whereas it is reportedly reduced in size inHelicoverpazea. Using confocal microscopy and brightfield imaging, we show that the Lyonet’s gland inHelicoverpazeais present and the size is relatively enlarged relative to other lepidopterans. We also examined whether glucose oxidase, an abundant enzyme found in labial salivary gland is also present in the extracts of Lyonet’s gland, but we found no evidence of that. Based on the size and accessibility of the Lyonet’s gland, future studies should include transcriptomic and proteomics studies inH.zeato provide evidence for potential functions.