Single-cell and bulk transcriptomics of the liver reveals potential targets of NASH with fibrosis

Fibrosis is characterized by the excessive production of collagen and other extracellular matrix (ECM) components and represents a leading cause of morbidity and mortality worldwide. Previous studies of nonalcoholic steatohepatitis (NASH) with fibrosis were largely restricted to bulk transcriptome profiles. Thus, our understanding of this disease is limited by an incomplete characterization of liver cell types in general and hepatic stellate cells (HSCs) in particular, given that activated HSCs are the major hepatic fibrogenic cell population. To help fill this gap, we profiled 17,810 non-parenchymal cells derived from six healthy human livers. In conjunction with public single-cell data of fibrotic/cirrhotic human livers, these profiles enable the identification of potential intercellular signaling axes (e.g., ITGAV-LAMC1, TNFRSF11B-VWF and NOTCH2-DLL4) and master regulators (e.g., RUNX1 and CREB3L1) responsible for the activation of HSCs during fibrogenesis. Bulk RNA-seq data of NASH patient livers and rodent models for liver fibrosis of diverse etiologies allowed us to evaluate the translatability of candidate therapeutic targets for NASH-related fibrosis. We identified 61 liver fibrosis-associated genes (e.g., AEBP1, PRRX1 and LARP6) that may serve as a repertoire of translatable drug target candidates. Consistent with the above regulon results, gene regulatory network analysis allowed the identification of CREB3L1 as a master regulator of many of the 61 genes. Together, this study highlights potential cell-cell interactions and master regulators that underlie HSC activation and reveals genes that may represent prospective hallmark signatures for liver fibrosis.

Molecular targets and approaches to restore autophagy and lysosomal capacity in neurodegenerative disorders

Autophagy is a catabolic process that promotes cellular fitness by clearing aggregated protein species, pathogens and damaged organelles through lysosomal degradation. The autophagic process is particularly important in the nervous system where post-mitotic neurons rely heavily on protein and organelle quality control in order to maintain cellular health throughout the lifetime of the organism. Alterations of autophagy and lysosomal function are hallmarks of various neurodegenerative disorders. In this review, we conceptualize some of the mechanistic and genetic evidence pointing towards autophagy and lysosomal dysfunction as a causal driver of neurodegeneration. Furthermore, we discuss rate-limiting pathway nodes and potential approaches to restore pathway activity, from autophagy initiation, cargo sequestration to lysosomal capacity.

When should splint treatment start for a tendinous mallet finger? A retrospective review of 319 fingers

In a 5-year retrospective review of 319 tendinous mallet fingers, we focused on the result after splint treatment. The splint we used was a 'no pressure' thermoformed customized Stack splint. The patients wore it strictly for 8 weeks. Based on the Patel criteria, we obtained 91% good or excellent results and 9% fair or poor results. The rate of excellent results increased significantly (p < 0.001) when treatment started 20 days after the trauma. Patients were 13 times more likely to have good or excellent results with a delayed treatment. We noticed that inflammation in the distal interphalangeal joint seemed to be detrimental to the healing process. We suggest assessing if there is inflammation to anticipate the failure of treatment, which will lead to a longer treatment. Further studies on the subject should confirm this.

Effects of antimicrobial exposure on the antimicrobial resistance of Escherichia coli in the digestive flora of dairy calves

Veal calves are often identified as reservoirs for antimicrobial resistant Escherichia coli (E. coli). This production is closely linked with dairy production, as young calves - mostly males - are collected from dairy farms to enter the fattening process. The aim of this prospective study was to explore the factors on dairy farms that favour the selection of antimicrobial resistance (AMR) in the digestive E. coli strains of young calves and to assess whether the resistance levels and selection pressure were the same for males and females. The exposure of calves to antimicrobials was investigated through three factors: antimicrobial treatment of calves; feeding of calves with milk from cows treated with antimicrobials; and the consumption of colostrum from cows treated with antimicrobials at dry-off. The study design involved 100 dairy farms. A calf of each sex was selected from birth on each farm. Information on the calves' exposure to antimicrobials was collected daily and calves were sampled (rectal swab) two weeks after birth, then seven weeks after birth for females only. Laboratory analyses included culture on two distinct media: a non-selective medium (identifying dominant flora) and a medium containing ceftiofur to select the extended-spectrum beta-lactamase (ESBL) phenotype. Susceptibility testing was performed on an E. coli strain from each medium. Generalised linear models were used to assess associations between the resistance of E. coli strains and antimicrobial exposure. A set of 280 swabs from healthy calves were analysed. In dominant flora, high levels of resistance (>60 %) were identified for streptomycin, tetracycline and amoxicillin but AMR levels were low (3 %) for critically important antimicrobials (3^rd- and 4^th-generation cephalosporins and fluoroquinolones). For females staying in dairy farms, a marked decrease in resistance was observed for almost all antimicrobials between the age of 15 days and 7 weeks. A selective medium revealed an ESBL phenotype for 20.7 % of the calves. Whether for AMR or antimicrobial exposure, no significant difference was found between male and female calves. The antimicrobial treatment of calves was associated with an increased resistance of E. coli from dominant flora for amoxicillin (OR = 2.9), gentamicin (OR = 4.6), florfenicol (OR = 5.0) and trimethoprim-sulfonamide (OR = 5.6). The consumption by calves of milk from cows treated with antimicrobials was also associated with an increased resistance to amoxicillin (OR = 2.6), gentamicin (OR = 4.0), tetracycline (2.6) and trimethoprim-sulfonamide (OR = 2.2). In contrast, the models did not reveal any association between AMR and consumption of colostrum from cows treated with antimicrobials at dry-off.

Stendomycin selectively inhibits TIM23-dependent mitochondrial protein import

Tim17 and Tim23 are the main subunits of the TIM23 complex, one of the two major essential mitochondrial inner-membrane protein translocon machineries (TIMs). No chemical probes that specifically inhibit TIM23-dependent protein import were known to exist. Here we show that the natural product stendomycin, produced by Streptomyces hygroscopicus, is a potent and specific inhibitor of the TIM23 complex in yeast and mammalian cells. Furthermore, stendomycin-mediated blockage of the TIM23 complex does not alter normal processing of the major regulatory mitophagy kinase PINK1, but TIM23 is required to stabilize PINK1 on the outside of mitochondria to initiate mitophagy upon membrane depolarization.

A retrospective review of 345 patients with lumbar TDR in two years follow-up over 10 years of practice in one Belgian clinical center : Results

Low back pain is one of the most common symptom with high cost for the public health. When conservative treatment fails, patients are heading to surgical treatment. Instead of lumbar arthrodesis, we can offer an alternative that will keep the intervertebral mobility : Total disc replacement (TDR) by prosthesis. Many studies have published good results rate over 80%, since first implantation in 1984. Believing in keeping the mobility, we promote TDR since 2002. This retrospective study review 345 patients with two years follow-up. The outcomes show 81% of good and really good results, according to gain of improvement on VAS and ODI scores. We report 6.88% of complications for the abdominal approach and 4.57% for the device, without harmful complication. Same results are obtained in case of postdiscectomy syndrome.

Greenhouse gas emissions from boreal reservoirs in Manitoba and Quebec, Canada, measured with automated systems

Growing concern over the contribution of freshwater reservoirs to increases in atmospheric greenhouse gas (GHG) concentrations and the relevance of long-term continuous measurements has led Fisheries and Oceans Canada, in conjunction with Manitoba Hydro, to develop continuous GHG monitors. Continuous water pCO(2), pCH(4), and pO(2) measurements were gathered to estimate gas fluxes in one temperate reservoir (Riviere-des-Prairies) and two boreal reservoirs (Eastmain-1 and Robert-Bourassa) in Quebec, and in four boreal reservoirs (Grand Rapids, Jenpeg, Kettle, and McArthur Falls) in Manitoba, Canada. Mean daily CO(2) fluxes ranged between 7 and 14 mmolCO(2)*m(-2)*d(-1) in Manitoba and between 15 and 55 mmolCO(2)*m(-2)*d(-1) in Quebec. Summertime episodes of water undersaturation in CO(2) were observed at Jenpeg, Kettle, and McArthur, suggesting higher productivities of these systems compared to the other systems studied. Mean daily CH(4) fluxes ranged between 0 and 69 micromolCH(4)*m(-2)*d(-1) in Manitoba and between 9 and 48 micromolCH(4)*m(-2)*d(-1) in Quebec. Comparisons of results obtained in the Eastmain-1 area using automated monitors, floating chambers or dissolved gas analyses over multiple-station field campaigns demonstrated that a continuous GHG monitor at a single sampling station provided representative and robust results.

The phosphoinositide 3-kinase/Akt pathway is essential for the retinoic acid-induced differentiation of F9 cells

Retinoic acid (RA) induces cell growth arrest and differentiation through two families of nuclear receptors, the RARs and the RXRs. The phosphoinositide 3-kinase (PI3K)/Akt pathway also plays key roles in these processes, that is, cell cycle progression, cell differentiation and cell survival. We report that, in mouse embryocarcinoma cells (F9 cells), RA induces an early activation of PI3K and Akt via an increase in the expression of the p85alpha regulatory subunit. This effect is followed by an inhibition of Akt. Both effects require the integrity of the RA pathway as they are not observed in RA-resistant RARgamma null cells. We propose a model through which RA induces a biphasic regulation of Akt with an activation participating to the differentiation process, followed by an inhibition, which has been correlated to the RA-induced growth arrest.

Involvement of MINK, a Ste20 Family Kinase, in Ras Oncogene-Induced Growth Arrest in Human Ovarian Surface Epithelial Cells

The ability of activated Ras to induce growth arrest of human ovarian surface epithelial (HOSE) cells via induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) has been used to screen for Ras pathway signaling components using a library of RNA interference (RNAi) vectors targeting the kinome. Two known Ras-regulated kinases were identified, phosphoinositide 3-kinase p110alpha and ribosomal protein S6 kinase p70(S6K1), plus the MAP kinase kinase kinase kinase MINK, which had not previously been implicated in Ras signaling. MINK is activated after Ras induction via a mechanism involving reactive oxygen species and mediates stimulation of the stress-activated protein kinase p38 MAPK downstream of the Raf/ERK pathway. p38 MAPK activation is essential for Ras-induced p21(WAF1/CIP1) upregulation and cell cycle arrest. MINK is thus a distal target of Ras signaling in the induction of a growth-arrested, senescent-like phenotype that may act to oppose oncogenic transformation in HOSE cells.

Phosphorylation of the retinoid x receptor at the omega loop, modulates the expression of retinoic-acid-target genes with a promoter context specificity

The retinoid response is mediated by two classes of nuclear receptors, the retinoic acid receptors (RARalpha, beta, and gamma) and the retinoid X receptors (RXRalpha, beta, and gamma) which act as ligand-dependent heterodimeric RAR/RXR transcription activators. Like most transcription factors, RARs and RXRs are regulated by phosphorylation processes. Here, we report that stress agents induce RXRalpha phosphorylation, subsequently to the activation of the stress-activated protein kinases cascade (JNKs). This phosphorylation process concerns three residues located in the N-terminal AF-1 domain of RXRalpha and one located in the omega loop of the Ligand Binding Domain. To decipher how stress-induced RXRalpha phosphorylation influences the transcription of RA-target genes, we used a ribotoxic stress agent, anisomycin, which activates signaling kinases without promoting DNA or protein damages, at subinhibitory concentrations. Taking advantage of vectors expressing recombinant RXRalpha mutated at its phosphorylation sites and of F9 cell lines re-expressing the same RXRalpha mutants in an RXRalpha null background, we provide evidence that stress signaling modulates RAR/RXRalpha-mediated transcription, through the phosphorylation of RXRalpha at the residue located in the Omega loop, in a promoter context-dependent manner.

Retinoic acid and arsenic trioxide cooperate for apoptosis through phosphorylated RXR alpha

Arsenite trioxide (As2O3) induces apoptosis in several cell lines by disturbing key signal transduction pathways through its oxidative properties. Here, we report that As2O3 also induces the phosphorylation of the retinoid receptor RXRalpha, subsequent to oxidative damages and the activation of the stress-activated protein kinases cascade (JNKs). We also report that RA amplifies both As2O3-induced phosphorylation of RXRalpha and apoptosis. Taking advantage of 'rescue' F9 cell lines expressing RXRalpha mutated at its phosphorylation sites, in an RXRalpha null background, we provide evidence that RXRalpha is a key element involved in that potentiating effect. Finally, we demonstrate that As2O3 also abrogates the transactivation of RA-target genes.

Nuclear retinoid receptors and the transcription of retinoid-target genes

The pleiotropic effects of retinoids are mediated by nuclear retinoid receptors (RARs and RXRs) which are ligand-activated transcription factors. In response to retinoid binding, RAR/RXR heterodimers undergo major conformational changes and orchestrate the transcription of specific gene networks, through binding to specific DNA response elements and recruiting cofactor complexes that act to modify local chromatin structure and/or engage the basal transcription machinery. Then the degradation of RARs and RXRs by the ubiquitin-proteasome controls the magnitude and the duration of the retinoid response. RARs and RXRs also integrate a variety of signaling pathways through phosphorylation events which cooperate with the ligand for the control of retinoid-target genes transcription. These different modes of regulation reveal unexpected levels of complexity in the dynamics of retinoid-dependent transcription.

The phosphorylation site located in the A region of retinoic X receptor alpha is required for the antiproliferative effect of retinoic acid (RA) and the activation of RA target genes in F9 cells

Mouse F9 embryocarcinoma cells constitute a well established cell autonomous model system for investigating retinoic acid (RA) signaling in vitro. RA induces the differentiation of F9 cells grown as monolayers into endodermal-like cells and decreases their rate of proliferation. Knock-out of the retinoic X receptor alpha (RXRalpha) gene abolishes endodermal differentiation and the induction of several endogenous RA-responsive genes. RXRalpha null cells are also drastically impaired in their antiproliferative response to RA. The role of the RXRalpha phosphorylation site located in the N-terminal A region (Ser(22)) has been investigated here by establishing cell lines re-expressing RXRalpha either wild type or mutated at the phosphorylation site (RXRalphaS22A) in a RXRalpha-null background. We show that Ser(22) is dispensable for RA-induced endodermal differentiation but is crucial for the expression of several RA-responsive genes. Ser(22) is also indispensable for the antiproliferative effect of RA and necessary for the RA-induced down-regulation of p21(CIP) and p27(KIP) CKIs proteins that are known to be involved in the control of cell cycle progression.

Down-regulation of the phosphatidylinositol 3-kinase/Akt pathway is involved in retinoic acid-induced phosphorylation, degradation, and transcriptional activity of retinoic acid receptor gamma 2

Nuclear retinoic acid (RA) receptors (RARs) are phosphorylated at conserved serine residues located in their N-terminal domain. Phosphorylation of RARgamma2 at these residues is increased in response to RA subsequently to the activation of p38MAPK. We show here that this RA-induced phosphorylation of RARgamma2 resulted from the down-regulation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. By overexpressing Akt and by using agents that activated or inhibited the PI3K/Akt pathway, we also demonstrated that the RA-induced down-regulation of the PI3K/Akt pathway targeted not only the phosphorylation of RARgamma2 but also the turnover and transcriptional activity of the receptor. Altogether these data indicate that the PI3K/Akt pathway plays an important role in retinoic acid signaling.

TFIIH interacts with the retinoic acid receptor gamma and phosphorylates its AF-1-activating domain through cdk7

Retinoic acid receptor gamma (RARgamma) is phosphorylated in COS-1 cells at two conserved serine residues located in the N-terminal region (serines 77 and 79 in RARgamma1 and serines 66 and 68 in RARgamma2) that contains the activation function AF-1. These serines are phosphorylated in vitro by cdk7, a cyclin-dependent kinase associated to cyclin H and MAT1 in the CAK complex (cdk7.cyclin H. MAT1), that is found either free or as a component of the transcription/DNA repair factor TFIIH. RARgamma is more efficiently phosphorylated by TFIIH than by CAK and interacts not only with cdk7 but also with several additional subunits of TFIIH. RARgamma phosphorylation and interaction with TFIIH occur in a ligand-independent manner. Our data demonstrate also that phosphorylation of the AF-1 function modulates RARgamma transcriptional activity in a response gene-dependent manner.

Inhibitory and stimulatory effects of somatostatin on two human pancreatic cancer cell lines: a primary role for tyrosine phosphatase SHP-1

Somatostatin (SS-14) and its structural analogue SMS 201-995 (SMS) are recognized as physiological inhibitors of multiple organs and tissue functions through specific membrane receptors (sst1-sst5). The effects of SS-14 and SMS in the growth control of the pancreatic cancer cell lines MIA PaCa-2 and PANC-1 were investigated to identify and clarify the intracellular events involved. In PANC-1 cells, SS-14 and SMS caused inhibition of their basal growth, and that stimulated by epidermal growth factor, with a maximal effect at 0.1-1 microM. To understand the inhibitory mechanisms, we investigated the effects of SS-14 and SMS on phosphotyrosine phosphatase (PTPase) activity and, more specifically, that of tyrosine phosphatase SHP-1 (PTP1C). SS-14 and SMS caused significant increases in total cellular PTPase activity, and particularly SHP-1, with maximal activation within 1 min. Inhibition of membrane tyrosine kinase and p42 MAP kinase activities was also observed, in response to SS-14 and SMS. In MIA PaCa-2 cells, SS-14 and SMS were associated with a positive growth response at 1-10 nM, after 4 days of culture in serum-free medium. Total cellular PTPase activity was slightly increased, but SHP-1 activity could not be detected; its absence in this cell line was confirmed by Western blot. Membrane tyrosine kinase activities were significantly increased by SS-14 and SMS at concentrations needed for maximal growth. p44/p42, which are constitutively active in this cell line, and p38 activities were not affected by somatostatin. In conclusion, somatostatin can exert different effects on human pancreatic cancer cell growth, depending upon the presence or absence of SHP-1. This enzyme can play a key role in the control of cell proliferation, and its cellular presence may determine the therapeutic potential of somatostatin in the control of cancer cell growth.

[5th day syndrome after appendectomy. Plea against surgical treatment straight off]

Thirteen cases of post-appendicectomy "fifth day syndrome" (0.45% of 2,919 children operated upon) are reported. The diagnosis must be established on precise criteria. Treatment is primarily medical, using antibiotics and anti-inflammatory drugs, and it must produce rapid and complete results. It is only when it fails (2 cases in our series) that a second operation is justified.

[Management of Meckel's diverticulum of fortuitous discovery]

A Meckel's diverticulum was discovered in 89 patients during routine exploration at the time of an appendicectomy. Subsequent treatment and complications of surgical correction of a Meckel's diverticulum are discussed. A different attitude appears necessary depending on whether the patient is a child or an adult : apart from some particular circumstances, a healthy diverticulum should be removed in children and left untouched in adults.

[Radical treatment of prepatellar and radiohumeral bursitis by excision and capitonnage (author's transl)]

Residual effusion after surgical operation for bursitis can be avoided by vertical incision immediate opening of the bursa which facilitates excision with minimal subcutaneous separation, followed by transcutaneous capitonnage, which suppresses any dead space.

[Transverse laparotomy by supre-pubic detachment of the recti muscles in gynecologic surgery. Apropos of 266 cases]

The authors have studied 266 case histories where supra-pubic detachment of rectus muscles was used according to Cherny's method. This allowed aseptic gynaecological surgery to be carried out in all its forms by a true transverse incision. The advantages are great : it is aesthetic and the incision can be enlarged if necessary indefinitely. This means that surgery can be carried out easily and explains the great rarity of intra-abdominal complications. On the other hand two relatively rare complications do occur with this incision : peritoneal haematomata and lateral herniations. Details have been given of the methods necessary to avoid these complications.

[An improved technique for transverse pelvic incisions: supra-pubian deinsertion of rectus abdominis (author's transl)]

Deinsertion of the rectus muscles allows an esthaetic supra-pubian transverse incision, enlargeable at will and yielding a solid repair. The technique has the same indications, and many more, as the Pfannenstiel incision. For those who keep on using the latter the present technique always enables the surgeon to transform a narrow field into a large transverse laporotomy.