Neuropathic pain induced by sciatic nerve injury involves epigenetic changes and chromatolytic damage in the somatosensory nervous system. Effects of miR-30c-5p gain and loss of function.

ABSTRACT: Neuropathic pain (NP) is a debilitating chronic syndrome that is often refractory to currently available analgesics. The maintenance of NP encompasses long term pathological plasticity in the nervous system that may be explained by alterations in the epigenetic mechanisms and cellular processes that underlie this disease. In this thesis, we investigated the involvement of epigenetic mechanisms in neuropathic pain establishment and chronification and the effects of modulating miR-30c-5p in the somatosensory nervous system. The transcript levels of DNA methyltransferase-3A and 3B were significantly up-regulated in the spinal dorsal horn and dorsal root ganglia from neuropathic rats. This upregulation was potentiated when neuropathic rats were treated with a miR-30c-5p inhibitor. In parallel, both structures exhibited increased methylation at cytosine in CpG islands. By luciferase assay, we demonstrated a post-transcriptional regulation for DNMT3B and DNMT3A by miR-30c-5p. Furthermore, we demonstrated that NP induces an increase in the chromatolytic damage suffered by DRG neurons. This phenomenon was potentiated when neuropathic rats were treated with a miR-30c-5p mimic. We showed that miR-30c-5p treatment induces reorganization and loss of nucleolar transcription units, segregation of dense fibrillar and granular components and a depletion of cajal bodies. We propose that miR-30c-5p modulation in NP plays an essential role in the epigenetic mechanism and cellular processes that underlie this disease.Esta tesis ha sido financiada con ayudas a la investigación procedentes de: - Beca predoctoral de Neurociencia: Fundación Tatiana Pérez de Guzmán el Bueno. - Instituto de investigación sanitaria Marqués de Valdecilla - Ministerio de Economía y Competitividad a través de los Proyectos del Plan Estatal: SAF2013-47434-R y SAF2016-77732-

Identification of Epigenetic Interactions between MicroRNA-30c-5p and DNA Methyltransferases in Neuropathic Pain

Neuropathic pain is a prevalent and severe chronic syndrome, often refractory to treatment, whose development and maintenance may involve epigenetic mechanisms. We previously demonstrated a causal relationship between miR-30c-5p upregulation in nociception-related neural structures and neuropathic pain in rats subjected to sciatic nerve injury. Furthermore, a short course of an miR-30c-5p inhibitor administered into the cisterna magna exerts long-lasting antiallodynic effects via a TGF-?1-mediated mechanism. Herein, we show that miR-30c-5p inhibition leads to global DNA hyper-methylation of neurons in the lumbar dorsal root ganglia and spinal dorsal horn in rats subjected to sciatic nerve injury. Specifically, the inhibition of miR-30-5p significantly increased the expression of the novo DNA methyltransferases DNMT3a and DNMT3b in those structures. Furthermore, we identified the mechanism and found that miR-30c-5p targets the mRNAs of DNMT3a and DNMT3b. Quantitative methylation analysis revealed that the promoter region of the antiallodynic cytokine TGF-?1 was hypomethylated in the spinal dorsal horn of nerve-injured rats treated with the miR-30c-5p inhibitor, while the promoter of Nfyc, the host gene of miR-30c-5p, was hypermethylated. These results are consistent with long-term protection against neuropathic pain development after nerve injury. Altogether, our results highlight the key role of miR-30c-5p in the epigenetic mechanisms' underlying neuropathic pain and provide the basis for miR-30c-5p as a therapeutic target.Funding: This work was supported by: Grant SAF2016-77732-R funded by MCIN/AEI/10.13039/ 501100011033 and by “ERDF A way of making Europe”; Grant PID2019-104398RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and Instituto de Investigación Sanitaria Valdecilla (IDIVAL) (NVAL17/23). R.F. was the recipient of a pre-doctoral fellowship of the Foundation Tatiana Pérez de Guzmán el Bueno. Acknowledgments: We acknowledge the excellent technical assistance of Nieves García Iglesias

Development and Validation of a Clinical-Genetic Risk Score to Predict Hepatic Encephalopathy in Patients With Liver Cirrhosis

[Introduction] We aimed to define the impact of the genetic background on overt hepatic encephalopathy (HE) in patients with liver cirrhosis by developing a combined clinical-genetic risk score.[Methods] Patients suffering from liver cirrhosis from the outpatient clinics of 4 hospitals (n = 600) were included and followed up for at least 5 years until HE bouts, liver transplant, or death. Patients were genotyped for 60 candidate single nucleotide polymorphisms together with the microsatellite in the promoter region of the gene GLS.[Results] Single nucleotide polymorphisms rs601338 (FUT2), rs5743836 (TRL9), rs2562582 (SLC1A3), rs313853 (SLC1A5), and GLS microsatellite did predict independently the incidence and severity of overt HE and were included as genetic score. Competing risk analysis revealed that bilirubin (subhazard ratio [sHR] 1.30 [1.15–1.48], P < 0.001), albumin (sHR 0.90 [0.86–0.93], P < 0.001), genetic score (sHR 1.90 [1.57–2.30], P < 0.001), and previous episodes of overt HE (sHR 2.60 [1.57–4.29], P < 0.001) were independently associated to HE bouts during the follow-up with an internal (C-index 0.83) and external validation (C-index 0.74). Patients in the low-risk group had 5% and 12% risk of HE at 1 (log-rank 92.1; P < 0.001) and 5 (log-rank 124.1; P < 0.001) years, respectively, whereas 36% and 48% in the high-risk group.[Discussion] The genetic background influenced overt HE risk and severity. The clinical-genetic HE Risk score, which combined genetic background together with albumin, bilirubin, and previous episodes of overt HE, could be a useful tool to predict overt HE in patients with cirrhosis.Peer reviewe

Definite and indeterminate nonalcoholic steatohepatitis share similar clinical features and prognosis: A longitudinal study of 1893 biopsy-proven nonalcoholic fatty liver disease subjects

[Background and Aim] Histological score systems may not fully capture the essential nonalcoholic steatohepatitis (NASH) features, which is one of the leading causes of screening failure in clinical trials. We assessed the NASH distribution and its components across the fibrosis stages and their impact on the prognosis and their relationship with the concept of metabolic-associated fatty liver disease (MAFLD).[Methods] Spanish multicenter study including 1893 biopsy-proven nonalcoholic fatty liver disease (NAFLD) patients from HEPAmet registry. NASH was diagnosed by NAS score ≥4 (including steatosis, ballooning and lobular inflammation) and fibrosis by Kleiner score. The presence of MAFLD was determined. Progression to cirrhosis, first episode of decompensated cirrhosis and death were collected during the follow-up (4.7 ± 3.8 years).[Results] Fibrosis was F0 34.3% (649/1893), F1 27% (511/1893), F2 16.5% (312/1893), F3 15% (284/1893) and F4 7.2% (137/1893). NASH diagnosis 51.9% (982/1893), and its individual components (severe steatosis, ballooning and lobular inflammation), increased from F0 (33.6%) to F2 (68.6%), and decreased significantly in F4 patients (51.8%) (P = .0001). More than 70% of non-NASH patients showed some inflammatory activity (ballooning or lobular inflammation), showing a similar MAFLD rate than NASH (96.2% [945/982] vs. 95.2% [535/562]) and significantly higher than nonalcoholic fatty liver (NAFL) subjects (89.1% [311/349]) (P < .0001). Progression to cirrhosis was similar between NASH (9.5% [51/539]) and indeterminate NASH (7.9% [25/316]), and higher than steatosis (5% [14/263]) (logRank 8.417; P = .015). Death and decompensated cirrhosis were similar between these.[Conclusions] The prevalence of steatohepatitis decreased in advanced liver disease. However, most of these patients showed some inflammatory activity histologically and had metabolic disturbances. These findings should be considered in clinical trials whose main aim is to prevent cirrhosis progression and complications, liver transplant and death.This project has been partially funded by the ‘Consejería de Salud de la Junta de Andalucía’ (PI-0075-2014) and the ‘Spanish Ministry of Economy, Innovation and Competition, Instituto de Salud Carlos III’ (PI19/01404, PI16/01842, PI17/00535 and GLD19/00100).Peer reviewe

Significant fibrosis predicts new-onset diabetes mellitus and arterial hypertension in patients with NASH

[Background & Aims] Non-alcoholic fatty liver disease (NAFLD) could play a catalytic role in the development of metabolic comorbidities, although the magnitude of this effect in metabolically healthy patients with NAFLD remains unclear. We assessed the role of biopsy-proven NAFLD on the risk of developing type 2 diabetes mellitus (T2DM) and other metabolic comorbidities (arterial hypertension [AHT], and dyslipidemia) in metabolically healthy patients.[Methods] We included 178 metabolically healthy—defined by the absence of baseline T2DM, AHT, dyslipidemia—patients with biopsy-proven NAFLD from the HEPAmet Registry (N = 1,030). Hepamet fibrosis score (HFS), NAFLD fibrosis score, and Fibrosis-4 were calculated. Follow-up was computed from biopsy to the diagnosis of T2DM, AHT, or dyslipidemia.[Results] During a follow-up of 5.6 ± 4.4 years, T2DM occurred in 9% (16/178), AHT in 8.4% (15/178), low HDL in 9.6% (17/178), and hypertriglyceridemia in 23.6% (42/178) of patients. In multivariate analysis, significant fibrosis predicted T2DM and AHT. Independent variables related to T2DM appearance were significant fibrosis (HR 2.95; 95% CI 1.19–7.31; p = 0.019), glucose levels (p = 0.008), age (p = 0.007) and BMI (p = 0.039). AHT was independently linked to significant fibrosis (HR 2.39; 95% CI 1.14–5.10; p = 0.028), age (p = 0.0001), BMI (p = 0.006), glucose (p = 0.021) and platelets (p = 0.050). The annual incidence rate of T2DM was higher in patients with significant fibrosis (4.4 vs. 1.2 cases per 100 person-years), and increased in the presence of obesity, similar to AHT (4.6 vs. 1.1 cases per 100 person-years). HFS >0.12 predicted the risk of T2DM (25% [4/16] vs. HFS 0.12, but not NAFLD fibrosis score or Fibrosis-4, predicted the occurrence of T2DM.[Lay summary] Patients with biopsy-proven non-alcoholic fatty liver disease and significant fibrosis were at risk of developing type 2 diabetes mellitus and arterial hypertension. The risk of metabolic outcomes in patients with significant fibrosis was increased in the presence of obesity. In addition to liver biopsy, patients at intermediate-to-high risk of significant fibrosis by Hepamet fibrosis score were at risk of type 2 diabetes mellitus.This project has been partially funded by the “Consejería de Salud de la Junta de Andalucía” (PI-0075-2014), the “Spanish Ministry of Economy, Innovation and Competition, Instituto de Salud Carlos III” (PI19/01404, PI16/01842 and PI17/00535) and “Gilead” (GLD19/00100)

Definite and indeterminate nonalcoholic steatohepatitis share similar clinical features and prognosis: A longitudinal study of 1893 biopsy‐proven nonalcoholic fatty liver disease subjects

[Background and Aim] Histological score systems may not fully capture the essential nonalcoholic steatohepatitis (NASH) features, which is one of the leading causes of screening failure in clinical trials. We assessed the NASH distribution and its components across the fibrosis stages and their impact on the prognosis and their relationship with the concept of metabolic-associated fatty liver disease (MAFLD).[Methods] Spanish multicenter study including 1893 biopsy-proven nonalcoholic fatty liver disease (NAFLD) patients from HEPAmet registry. NASH was diagnosed by NAS score ≥4 (including steatosis, ballooning and lobular inflammation) and fibrosis by Kleiner score. The presence of MAFLD was determined. Progression to cirrhosis, first episode of decompensated cirrhosis and death were collected during the follow-up (4.7 ± 3.8 years).[Results] Fibrosis was F0 34.3% (649/1893), F1 27% (511/1893), F2 16.5% (312/1893), F3 15% (284/1893) and F4 7.2% (137/1893). NASH diagnosis 51.9% (982/1893), and its individual components (severe steatosis, ballooning and lobular inflammation), increased from F0 (33.6%) to F2 (68.6%), and decreased significantly in F4 patients (51.8%) (P = .0001). More than 70% of non-NASH patients showed some inflammatory activity (ballooning or lobular inflammation), showing a similar MAFLD rate than NASH (96.2% [945/982] vs. 95.2% [535/562]) and significantly higher than nonalcoholic fatty liver (NAFL) subjects (89.1% [311/349]) (P < .0001). Progression to cirrhosis was similar between NASH (9.5% [51/539]) and indeterminate NASH (7.9% [25/316]), and higher than steatosis (5% [14/263]) (logRank 8.417; P = .015). Death and decompensated cirrhosis were similar between these.[Conclusions] The prevalence of steatohepatitis decreased in advanced liver disease. However, most of these patients showed some inflammatory activity histologically and had metabolic disturbances. These findings should be considered in clinical trials whose main aim is to prevent cirrhosis progression and complications, liver transplant and death.This project has been partially funded by the ‘Consejería de Salud de la Junta de Andalucía’ (PI-0075-2014) and the ‘Spanish Ministry of Economy, Innovation and Competition, Instituto de Salud Carlos III’ (PI19/01404, PI16/01842, PI17/00535 and GLD19/00100).Peer reviewe