POS0425 INCREASED KERATIN 9 EXPRESSION IN SYSTEMIC SCLEROSIS SKIN IS DRIVEN BY THE lncRNA HOTAIR FROM FIBROBLAST DERIVED EXOSOMES

Background:

Skin fibrosis is the hallmark fibrotic manifestation of systemic sclerosis (SSc). Despite a key role of tissue fibroblasts, skin changes extend to the keratinocyte layer, which contribute to the loss of skin function. RNA seq. analysis of SSc patient forearm skin showed that palmoplantar specific Keratin 9 (CK9) was highly expressed (1). SSc affected skin shares several features with palmoplantar skin including increased keratinocyte layer thickness and lack of hair. Seminal work of last decade has shown that long noncoding RNA in the HOX loci play a crucial role in skin keratinocyte differentiation (2), with the lncRNA HOTAIR being one of the HOX lncRNA mostly expressed in the palmoplantar region.

Objectives:

Following recent data suggesting a role of HOTAIR in the profibrotic phenotype of dermal fibroblasts in SSc (3), here we set out to determine if HOTAIR expressed in SSc dermal fibroblasts was a contributing factor to the high levels of CK9 found in SSc patient skin

Methods:

Full-thickness skin biopsies were surgically obtained from the forearms of patients with SSc of recent onset. Fibroblasts were isolated and cultured in monolayers. HOX transcript antisense RNA (HOTAIR) was expressed in healthy dermal fibroblasts by lentiviral induction employing a vector containing the specific sequence. Exosomes were isolated from dermal fibroblast media using the Total exosome isolation reagent (Thermo Fisher). Enhancer of zeste 2 (EZH2) was blocked with GSK126 inhibitor. Skin equivalents were created using scramble and HOTAIR expressing fibroblasts with primary keratinocytes

Results:

Media from both SSc patient fibroblasts and HOTAIR expressing fibroblasts induced CK9 expression in healthy keratinocytes in vitro. In addition, HOTAIR expressing fibroblasts induces CK9 expression in keratinocytes in 3D skin equivalent models. Media fractionation studies indicated that HOTAIR was present in fibroblasts exosomes and found at a higher concentration (2.7 fold p=0.01) in exosomes from SSc fibroblasts. Importantly, transfection of Exosomal RNAs from SSc fibroblasts could reproduce the increase in CK9 in keratinocytes. Mechanistically, CK9 induction was mediated by changes to the histone methylation profile in the keratinocytes through EZH2.

Conclusion:

Pro-fibrotic dermal fibroblasts in systemic sclerosis contribute to the overall skin loss of function by inducing CK9 in adjacent keratinocytes through transfer of the long non-coding RNA HOTAIR. Unraveling the crosstalk of activated fibroblasts with adjacent cells may lead to identify therapeutic targets to re-establish tissue homeostasis and function during fibrosis.

References:

[1]Assassi S et.al Arthritis and Rheumatology 2015

[2]Rinn JL et.al Cell 2007

[3]Wasson CW et.al Annals of Rheumatic Disease 2020

Disclosure of Interests:

Chris Wasson: None declared, rebecca ross: None declared, Jessica Bryon: None declared, Francesco Del Galdo Speakers bureau: Speakers bureau: Astra-Zeneca, Boehringer Ingelheim, Actelion, Consultant of: Astra-Zeneca, Mitsubishi-Tanabe, Capella Biosciences, Chemomab, Actelion, Boehringer-Ingelheim, Grant/research support from: Grant/research support from: Capella Biosciences, Chemomab, Kymab, Mitsubishi-Tanabe

P149 The intracellular chloride channel 4 (CLIC4) plays an important role in systemic sclerosis fibroblast activation

Background/Aims 

The intracellular chloride ion channel CLIC4 mediates the activation of cancer associated fibroblasts. Interestingly, systemic sclerosis (SSc) fibroblasts display a number of similar properties to cancer associated fibroblasts. Tissue fibrosis in SSc is driven by active fibroblasts (myofibroblasts). Therefore in this study we investigated the role of CLIC4 in SSc fibroblast activation.

Methods 

Dermal fibroblasts were obtained from full thickness skin biopsies from SSc patients (early-diffuse). RNA and protein were collected from the fibroblasts and CLIC4 transcript and protein levels were assessed by qPCR and western blot. SSc patient fibroblasts were treated with the chloride ion channel inhibitors NPPB and IAA-94.

Results 

CLIC4 was found to be expressed at significantly higher levels in SSc patients fibroblasts compared to healthy controls, at both the transcript (3.7 fold) and protein (1.7 fold) levels. Inhibition of the TGF-β signalling pathway led to reduced CLIC4 expression in SSc fibroblasts, confirming this pathway as the main driver of CLIC4 expression. Finally, treatment of SSc fibroblasts with small molecule inhibitors that target the channel led to reduced expression of the myofibroblast markers collagen type 1 and alpha-smooth muscle actin, suggesting a direct role for CLIC4 in SSc associated skin fibrosis.

Conclusion 

We have identified a novel role for CLIC4 in SSc myofibroblast activation, which further strengthen the similarities between SSc fibroblasts and cancer associated fibroblasts. Furthermore this study highlights this channel as a novel target for therapeutic intervention.

Disclosure 

C. Wasson: None. R. Ross: None. R. Morton: None. J. Mankouri: None. F. Del Galdo: None.

SAT0281 BIOSAMPLES FROM AT RISK SSC PATIENTS SHOW CLASSIC PATHOLOGICAL SIGNS OF SCLERODERMA: OPPORTUNITY FOR DIAGNOSIS OF PRE-CLINICAL SSC

Background:

The VEDOSS study has recently indicated that more than 80% of patients affected by Raynaud’s phenomenon (RP) with specific SSc auto-antibodies and capillaroscopy changes satisfied ACR/EULAR 2013 criteria within 5 years. These data suggest that there is a window of opportunity for early detection of SSc in these patients.

Objectives:

Here we aimed to determine whether sera, skin biopsies and skin fibroblasts cultured from these patients showed any biomarker sign of SSc.

Methods:

Fifty-nine at risk patients identified by having RP and SSc auto-antibodies or capillaroscopy pattern (or both) were enrolled in the Kennedy national inception cohort. Sera were tested for IFN inducible chemokines (CXCL-9,10 and 11 and CCL2, 8 and 19) and biomarker of extracellular matrix turnover (ELF test), all previously shown to be increased in SSc. Further, two 3mm skin biopsies were taken from the forearms from 3 ACA+ve (anti-centromere antibodies), 3 SCL70+ve patients. One biopsy was subjected to histology analysis, including haematoxylin and eosin staining and immunohistological staining for Collagen Type 1, alpha-SMA, Caveolin 1 and CD31 as endothelial marker. The other biopsy was used to explant fibroblasts cultures. mRNA and protein were isolated from primary fibroblasts and processed for RT-qPCR and western blotting analyses.

Results:

Sera from at risk patients showed overall higher IFN inducible chemokines and ELF test (P<0.05) with bimodal distribution among patients. Skin biopsies from both ACA or SCL70+ve patients showed decreased number of CD31+ cells, increased number of myofibroblasts and increased collagen bundles within the dermis, as usually seen in SSc, compared to healthy controls. In vitro, fibroblasts from both ACA or SCL70+ve patients showed average 10-fold higher collagen mRNA levels and 31-fold increased collagen protein levels

compared to healthy control fibroblasts. Furthermore, fibroblasts from ACA or SCL70+ve patients showed limited TGF-beta induced increase in collagen and SMA expression, similar to SSc fibroblasts.

Conclusion:

Although pilot in nature, this study suggests that patients “at risk” already show biomarker signs of SSc both in their sera, at skin biopsy and fibroblast level. Longitudinal studies on patients at this stage of pre-clinical disease may inform on the stratification strategies for imminent progression to clinical manifestations, and offer both insights on pathogenesis of clinical signs and a window of opportunity for delaying the onset clinical intervention trials.

Disclosure of Interests:

rebecca ross: None declared, Ioanna Georgiou: None declared, Antonio Carriero: None declared, Giuseppina Abignano: None declared, Chris Wasson: None declared, Gemma Migneco: None declared, Ariane Herrick: None declared, Christopher Denton Grant/research support from: GlaxoSmithKline, CSL Behring, and Inventiva, Consultant of: Medscape, Roche-Genentech, Actelion, GlaxoSmithKline, Sanofi Aventis, Inventiva, CSL Behring, Boehringer Ingelheim, Corbus Pharmaceuticals, Acceleron, Curzion and Bayer, Francesco Del Galdo: None declared

Inhibition of Plk1 and Cyclin B1 expression results in panobinostat-induced G₂ delay and mitotic defects

The development of clinically useful histone deacetylase inhibitors has expanded greatly. In a preclinical study, we showed that panobinostat (LBH589) inhibits cell cycle progression of human head and neck squamous cell carcinoma (HNSCC) cell lines at G₂/M and an associated decrease in expression of particular genes required for passage through G₂ and mitosis. In this study we sought to analyse the mechanistic underpinnings of panobinostat-induced growth arrest. HNSCC cell lines were synchronised and progression through mitosis monitored. We demonstrate that panobinostat causes a marked G₂ delay and mitotic defects. A loss of G₂-specific Plk1 and Cyclin B1 expression and co-incident increase in p21(Waf1/Cip1) expression is also shown. Furthermore, we show a significant loss of E2F1 recruitment to the promoters of these genes in response to panobinostat treatment. These data provide mechanistic evidence of panobinostat-induced cell cycle arrest and highlight its potential as a chemotherapeutic agent for HNSCC.

Binge alcohol consumption by non-alcohol-dependent women during pregnancy affects child behaviour, but not general intellectual functioning; a prospective controlled study

Effects of binge ethanol consumption during early gestation on child neurodevelopment have not been elucidated. To study whether binge drinking affects cognitive abilities and behavior of exposed children, a prospective observational study comparing 51 children exposed to binge drinking during the first trimester of pregnancy to 51 children not exposed to any teratogens was conducted. The children's physical development, intelligence, language abilities and behavior were assessed. Temperament test results showed that children exposed in utero to maternal binge drinking displayed a greater degree of disinhibited behavior and that this behavior was associated with early drinking variables. Although binge alcohol drinking by non-alcohol-dependent women during the first trimester of pregnancy does not appear to affect intelligence or cognitive and language development of young children, binge drinking in pregnancy does increase the likelihood of certain behavioral characteristics that might predispose these children to later behavioral dysfunction.

Long-term neurological sequelae of hemolytic-uremic syndrome: a preliminary report

Seven patients with hemolytic-uremic syndrome who had major neurological symptoms during the acute illness were neurologically and cognitively evaluated prospectively several years after recovery from the illness. Four patients showed evidence of subtle neurological sequelae, including posturing, clumsiness, poor fine-motor coordination, hyperactivity, and distractibility. Psychoeducational evaluation of all seven subjects revealed mean scores within the average range in cognitive abilities, academic achievement, single word receptive vocabulary, visual/motor planning, overall adaptive functioning, and hyperactivity. The lapse of time (minimum of 7 years) between the acute illness and the psychometric evaluation could have been responsible for our normal results.

Anti-p57: a novel association with neonatal lupus

IgG antibodies to a 57-kD protein (p57) present in various human and bovine extracts were detected by immunoblotting in the serum of the mother of a baby with congenital heart block, but not in the corresponding cord blood, suggesting specific antibody consumption in the baby. Since this indicates a possible functional role for these antibodies, the antigen target was characterized and the association of the antibodies to heart block was further studied. A human K562 lambda gt11 cDNA library was screened and two clones were identified whose products reacted with the prototype serum. Antibody affinity-purified by use of the cloned gene products reacted on immunoblot with the 57-kD band. Partial sequences of both inserts were identical, but differed from DNA encoding the Ro(SSA) and La(SSB) antigens. Antibodies to the p57 were detected in 10% of systemic lupus erythematosus (SLE) sera, almost exclusively in association with anti-Ro(SSA). Furthermore, they were present in 38% (8/21) mothers of babies with neonatal lupus expressing either cardiac or cutaneous manifestations. Antibodies to this 57-kD protein may be an additional risk factor for neonatal lupus in anti-Ro-positive women. Moreover, disappearance of antibody from cord blood suggests that they may have a role in disease manifestations.

An unusual nasal foreign body

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Erythrocyte pyruvate kinase deficiency in the Ohio Amish: origin and characterization of the mutant enzyme

We have identified eight individuals in an Amish population in Geauga County, Ohio, who have a congenital hemolytic anemia and red cell pyruvate kinase (PK) deficiency. The mutant enzyme is a low Km phosphoenolpyruvate (PEP) variant associated with a slower (77.5% of normal) electrophoretic mobility in starch gel. Because of the high consanguinity in this population, we assume the affected individuals are homozygous for the mutant gene. Genealogical records allow us to trace all eight cases back to a common ancestor who lived in Mifflin County, Pennsylvania. His sister was a common ancestor to all cases of PK deficiency originally described in the Pennsylvania Amish isolate. Therefore, all cases of PK deficiency in the Amish arose from a common ancestral pair.