Identification of VHY/Dusp15 as a Regulator of Oligodendrocyte Differentiation through a Systematic Genomics Approach

<div><p>Multiple sclerosis (MS) is a neuroinflammatory disease characterized by a progressive loss of myelin and a failure of oligodendrocyte (OL)-mediated remyelination, particularly in the progressive phases of the disease. An improved understanding of the signaling mechanisms that control differentiation of OL precursors may lead to the identification of new therapeutic targets for remyelination in MS. About 100 mammalian Protein Tyrosine Phosphatases (PTPs) are known, many of which are involved in signaling both in health and disease. We have undertaken a systematic genomic approach to evaluate PTP gene activity in multiple sclerosis autopsies and in related <em>in vivo</em> and <em>in vitro</em> models of the disease. This effort led to the identification of Dusp15/VHY, a PTP previously believed to be expressed only in testis, as being transcriptionally regulated during OL differentiation and in MS lesions. Subsequent RNA interference studies revealed that Dusp15/VHY is a key regulator of OL differentiation. Finally, we identified PDGFR-beta and SNX6 as novel and specific Dusp15 substrates, providing an indication as to how this PTP might exert control over OL differentiation.</p> </div

Intraoperative individualization of positive-end-expiratory pressure through electrical impedance tomography or esophageal pressure assessment: a systematic review and meta-analysis of randomized controlled trials

Purpose: This systematic review of randomized-controlled trials (RCTs) with meta-analyses aimed to compare the effects on intraoperative arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2), exerted by positive end-expiratory pressure (PEEP) individualized trough electrical impedance tomography (EIT) or esophageal pressure (Pes) assessment (intervention) vs. PEEP not tailored on EIT or Pes (control), in patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach. Methods: PUBMED®, EMBASE®, and Cochrane Controlled Clinical trials register were searched for observational studies and RCTs from inception to the end of August 2022. Inclusion criteria were: RCTs comparing PEEP titrated on EIT/Pes assessment vs. PEEP not individualized on EIT/Pes and reporting intraoperative PaO2/FiO2. Two authors independently extracted data from the enrolled investigations. Data are reported as mean difference and 95% confidence interval (CI). Results: Six RCTs were included for a total of 240 patients undergoing general anesthesia for surgery, of whom 117 subjects in the intervention group and 123 subjects in the control group. The intraoperative mean PaO2/FiO2 was 69.6 (95%CI 32.-106.4 ) mmHg higher in the intervention group as compared with the control group with 81.4% between-study heterogeneity (p < 0.01). However, at meta-regression, the between-study heterogeneity diminished to 44.96% when data were moderated for body mass index (estimate 3.45, 95%CI 0.78-6.11, p = 0.011). Conclusions: In patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach, PEEP personalized by EIT or Pes allowed the achievement of a better intraoperative oxygenation compared to PEEP not individualized through EIT or Pes. Prospero registration number: CRD 42021218306, 30/01/2023

Ten-point standardized rating scale for EAE clinical score monitoring.

<p>The final score for each animal is determined by the addition of all the above mentioned categories. Note: Score  =  15 for dead animal.</p

PTPs the most strongly modulated during EAE in mice spinal cord and cerebellum.

<p>Number of PTP genes significantly modulated during the EAE time course in the spinal cord and in the cerebellum has been monitored and represented in two graphics. The number of PTP genes modulated increases dramatically over time. At day 28, the number of PTP genes modulated decreases until a basal level in cerebellum but remains high in the spinal cord. The highest fold changes in gene expression versus Sham animals have been reported in the table. Most of these PTPs have already been described in inflammatpry processes. Statistical analysis were performed using student <i>t-</i>test.</p

Phosphatase activity of GST-tagged full length Dusp15/VHY.

<p>A. Dusp15 phosphatase activity was assessed using the DiFMUP (6,8-difluoro-4-methyumbelliferyl phosphate) assay at the experimentally optimal enzyme concentration of 4 ng/mL. B. Optimal pH activity (pH 6) was determined by testing a pH range from pH 3 to 8. C. and D. Activity of Dusp15/VHY on phospho-peptides substrates corresponding respectively to pY₁₁₉ and pY₇₇₁ dephosphorylation sites of SNX6 (NED(pY₁₁₉)AGYIIPPAP) and PDGFR-β (IESSN(pY₇₇₁)MAPYD). VHY/Dusp15 was used at 4 ng/mL at pH6 and activity was detected using the Malachite Green phosphate detection assay. OD, Optical Density at 620 nm. Dissociation constant (Km) was calculated as the substrate concentration needed to reach V_max/2 and expressed as Mean ± S_EM of three different experiments.</p

Correlation chart between MBP expression and dusp15 expression over a time course of differentiation in olineu.

<p>Values expressed as fold induction <i>versus</i> undifferentiated controls (starting cultures) and correspond to the Mean ± SD of two different experiments (n = 2). Dusp15/VHY expression increases with time and correlates with MBP expression during the first steps of Oli-neu differentiation then Dusp15 expression reaches a maximum at 15 h prior to the MBP expression peak occurring at 24 h.</p

Literature data for expression of selected PTPs in purified cells from rodent brain.

a<p>Data extracted from GEO dataset GSE9566: GSM241928 (56A); GSM241929 (61D); GSM241930 (69E); GSM241931 (72A); GSM241932 (79E); GSM241933 (80O); GSM241934 (80P); GSM241935 (80Q); GSM241936 (81A); GSM241937 (81B). Samples designations correspond to the one used by the cited authors. Cell types were purified from post-natal mouse forebrains using FACS analysis. For more details see <i>Cahoy et al</i>, 2007.</p>b<p>Data extracted from Geo dataset GDS2379: GSM138218-GSM138222 (n = 5); GSM138223-GSM138229 (n = 4). OL cell types were purified from post-natal P7 rats using FACS analysis. For more details see Nielsen <i>et al</i>, 2006.</p

Schematic overview of the experimental approach.

<p>Schematic overview of the experimental approach.</p

Oligonucleotides sequences.

<p>Oligonucleotides sequences.</p

Clinical data of MS and control autopsies included in the study.

*<p><i>CWM</i>: Control white matter; <i>CGM</i>: Control gray matter; <i>NAWM</i>: Normal appearing white matter; <i>WML</i>: White matter lesioned; <i>NAGM</i>: Normal appearing gray matter; <i>GML</i>: Gray matter lesioned.</p