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Chronic hyperammonemia, a main contributor to hepatic encephalopathy (HE), leads to neuroinflammation which alters neurotransmission leading to cognitive impairment. There are no specific treatments for the neurological alterations in HE. Extracellular vesicles (EVs) from mesenchymal stem cells (MSCs) reduce neuroinflammation in some pathological conditions. The aims were to assess if treatment of hyperammonemic rats with EVs from MSCs restores cognitive function and analyze the underlying mechanisms. EVs injected in vivo reach the hippocampus and restore performance of hyperammonemic rats in object location, object recognition, short-term memory in the Y-maze and reference memory in the radial maze. Hyperammonemic rats show reduced TGFβ levels and membrane expression of TGFβ receptors in hippocampus. This leads to microglia activation and reduced Smad7–IkB pathway, which induces NF-κB nuclear translocation in neurons, increasing IL-1β which alters AMPA and NMDA receptors membrane expression, leading to cognitive impairment. These effects are reversed by TGFβ in the EVs from MSCs, which activates TGFβ receptors, reducing microglia activation and NF-κB nuclear translocation in neurons by normalizing the Smad7–IkB pathway. This normalizes IL-1β, AMPA and NMDA receptors membrane expression and, therefore, cognitive function. EVs from MSCs may be useful to improve cognitive function in patients with hyperammonemia and minimal HE., This work was supported in part by the Ministerio de Ciencia e Innovación Spain (PID2020-113388RB-I00), Consellería Educación Generalitat Valenciana (PROMETEOII/2018/051; CIPROM2021/082), and co-funded with European Regional Development Funds (ERDF). PIA has a contract from Ministerio de Ciencia, Innovación y Universidades (FPU17/01698) and ACP from Instituto de Salud Carlos III (Postdoctoral Sara Borrell, CD17/00031).

Hyperammonemic rats show peripheral inflammation, increased GABAergic neurotransmission and neuroinflammation in cerebellum and hippocampus which induce motor incoordination and cognitive impairment. Neuroinflammation enhances GABAergic neurotransmission in cerebellum by enhancing the TNFR1-glutaminase-GAT3 and TNFR1-CCL2-TrkB-KCC2 pathways. Golexanolone reduces GABARats were treated with golexanolone and effects on peripheral inflammation, neuroinflammation, TNFR1-glutaminase-GAT3 and TNFR1-CCL2-TrkB-KCC2 pathways, and cognitive and motor function were analyzed.Hyperammonemic rats show increased TNFα and reduced IL-10 in plasma, microglia and astrocytes activation in cerebellum and hippocampus, and impaired motor coordination and spatial and short-term memories. Treating hyperammonemic rats with golexanolone reversed changes in peripheral inflammation, microglia and astrocytes activation and restored motor coordination and spatial and short-term memory. This was associated with reversal of the hyperammonemia-enhanced activation in cerebellum of the TNFR1-glutaminase-GAT3 and TNFR1-CCL2-TrkB-KCC2 pathways.Reducing GABA

T-cell receptor (TCR) analysis is relevant for the study of immune system diseases. The expression of TCRs is usually measured with targeted sequencing approaches where TCR genes are selectively amplified. However, many non-targeted RNA-seq experiments also contain reads of TCR genes, which could be leveraged for TCR expression analysis while reducing sample requirements and costs. Moreover, a step-by-step pipeline for the processing of transcriptome RNA-seq reads to deliver immune repertoire data is missing, and these types of analyses are usually not included in RNA-seq studies of immunological conditions. This represents a missed opportunity for complementing them with the analysis of the immune repertoire., We present a Nextflow pipeline for T-cell receptor repertoire reconstruction and analysis from RNA sequencing data. We used a case study where TCR repertoire profiles were recovered from bulk RNA-seq of isolated CD4 T cells from control patients, cirrhotic patients without and with Minimal Hepatic Encephalopathy (MHE). MHE is a neuropsychiatric syndrome, mediated by peripheral inflammation, that may affect cirrhotic patients. After the recovery of 498-1,114 distinct TCR beta chains per patient, repertoire analysis of patients resulted in few public clones, high diversity and elevated within-repertoire sequence similarity, independently of immune status. Additionally, TCRs associated with celiac disease and inflammatory bowel disease were significantly overrepresented in MHE patient repertoires. The provided computational pipeline functions as a resource to facilitate TCR profiling from RNA-seq data boosting immunophenotype analyses of immunological diseases., We acknowledge generous support by The Leona M. and Harry B. Helmsley Charitable Trust (#2019PG-T1D011, to VG), UiO World-Leading Research Community (to VG), UiO:LifeScience Convergence Environment Immunolingo (to VG), EU Horizon 2020 iReceptorplus (#825821) (to VG), a Research Council of Norway FRIPRO project (#300740, to VG), a Research Council of Norway IKTPLUSS project (#311341, to VG), a Norwegian Cancer Society Grant (#215817, to VG). This work was also supported in part by Fundación Ramón Areces (to CM), the Ministerio de Ciencia e Innovación Spain (SAF2017-82917-R and PID2020-113388RB-I00 to VF; FIS PI18/00150 to CM), Consellería Educación Generalitat Valenciana (PROMETEOII/2018/051 to VF), Ministerio de Economía y Competitividad (BIO2015-71658-R to AC), Centro de Investigación Príncipe Felipe (Ayudas para proyectos de investigación intergrupos to TR) and co-funded with European Regional Development Funds (ERDF to VF, CM, AC).

Minimal hepatic encephalopathy is associated with changes in the peripheral immune system which are transferred to the brain, leading to neuroinflammation and thus to cognitive and motor impairment. Mechanisms by which changes in the immune system induce cerebral alterations remain unclear. Extracellular vesicles (EVs) seem to play a role in this process in certain pathologies. The aim of this work was to assess whether EVs play a role in the induction of neuroinflammation in cerebellum and motor incoordination by chronic hyperammonemia. We characterized the differences in protein cargo of EVs from plasma of hyperammonemic and control rats by proteomics and Western blot. We assessed whether injection of EVs from hyperammonemic to normal rats induces changes in neuroinflammation in cerebellum and motor incoordination similar to those exhibited by hyperammonemic rats. We found that hyperammonemia increases EVs amount and alters their protein cargo. Differentially expressed proteins are mainly associated with immune system processes. Injected EVs enter Purkinje neurons and microglia. Injection of EVs from hyperammonemic, but not from control rats, induces motor incoordination, which is mediated by neuroinflammation, microglia and astrocytes activation and increased IL-1b, TNF&alpha, its receptor TNFR1, NF-kB in microglia, glutaminase I, and GAT3 in cerebellum. Plasma EVs from hyperammonemic rats carry molecules necessary and sufficient to trigger neuroinflammation in cerebellum and the mechanisms leading to motor incoordination.

BACKGROUND & AIMS Learning ability may be impaired in patients with a history of overt hepatic encephalopathy (OHE). The aim of this study was to compare performance on the first/second attempt at a series of tests. METHODS Two hundred and fourteen patients with cirrhosis were enrolled. On the day of study, 41% were classed as unimpaired, 38% as having minimal HE and 21% as having mild OHE; 58% had a history of OHE. Performance was compared between two versions of the trail-making test A (TMT-A), and between the first/second half of a simple/choice reaction time (sRT and cRT), and a working memory test (ScanRT). RESULTS Both patients with and without OHE history improved in TMT-A, sRT and ScanRT. Only patients with no OHE history improved in cRT. All patients, regardless of their HE status on the day of study, improved in TMT-A and sRT. Only patients with mild OHE on the day of study improved in cRT. Only unimpaired patients improved in ScanRT. When OHE history and HE status on the day of study were tested together, only HE status had an effect. The same held true when age, the Model for End Stage Liver Disease (MELD) and educational attainment were adjusted for. CONCLUSIONS HE status on the day of study and the type of neuropsychological test had an effect on learning ability in a well-characterized group of patients with cirrhosis.

Several million patients with liver cirrhosis suffer minimal hepatic encephalopathy (MHE), with mild cognitive and coordination impairments that reduce their quality of life and life span. Hyperammonaemia and peripheral inflammation act synergistically to induce these neurological alterations. We propose that MHE appearance is because of the changes in peripheral immune system, which are transmitted to brain, leading to neuroinflammation that alters neurotransmission leading to cognitive and motor alterations. We summarize studies showing that MHE in cirrhotic patients is associated with alterations in the immune system and that patients died with HE show neuroinflammation in cerebellum, with microglial and astrocytic activation and Purkinje cell loss. We also summarize studies in animal models of MHE on the role of peripheral inflammation in neuroinflammation induction, how neuroinflammation alters neurotransmission and how this leads to cognitive and motor alterations. These studies identify therapeutic targets and treatments that improve cognitive and motor function. Rats with MHE show neuroinflammation in hippocampus and altered NMDA and AMPA receptor membrane expression, which impairs spatial learning and memory. Neuroinflammation in cerebellum is associated with altered GABA transporters and extracellular GABA, which impair motor coordination and learning in a Y maze. These alterations are reversed by treatments that reduce peripheral inflammation (anti-TNFα, ibuprofen), neuroinflammation (sulphoraphane, p38 inhibitors), GABAergic tone (bicuculline, pregnenolone sulphate) or increase extracellular cGMP (sildenafil or cGMP). The mechanisms identified would also occur in other chronic diseases associated with inflammation, aging and some mental and neurodegenerative diseases. Treatments that improve MHE may also be beneficial to treat these pathologies.