Transforming Growth Factor β and Insulin Signal Changes in Stromal Fibroblasts of Individual Keratoconus Patients

Keratoconus (KC) is a complex thinning disease of the cornea that often requires transplantation. The underlying pathogenic molecular changes in this disease are poorly understood. Earlier studies reported oxidative stress, metabolic dysfunctions and accelerated death of stromal keratocytes in keratoconus (KC) patients. Utilizing mass spectrometry we found reduced stromal extracellular matrix (ECM) proteins in KC, suggesting ECM-regulatory changes that may be due to altered TGFβ signals. Here we investigated properties of stromal cells from donor (DN) and KC corneas grown as fibroblasts in serum containing DMEM: F12 or in serum-free medium containing insulin, transferrin, selenium (ITS). Phosphorylation of SMAD2/3 of the canonical TGFβ pathway, was high in serum-starved DN and KC fibroblast protein extracts, but pSMAD1/5/8 low at base line, was induced within 30 minutes of TGFβ1 stimulation, more so in KC than DN, suggesting a novel TGFβ1-SMAD1/5/8 axis in the cornea, that may be altered in KC. The serine/threonine kinases AKT, known to regulate proliferation, survival and biosynthetic activities of cells, were poorly activated in KC fibroblasts in high glucose media. Concordantly, alcohol dehydrogenase 1 (ADH1), an indicator of increased glucose uptake and metabolism, was reduced in KC compared to DN fibroblasts. By contrast, in low glucose (5.5 mM, normoglycemic) serum-free DMEM and ITS, cell survival and pAKT levels were comparable in KC and DN cells. Therefore, high glucose combined with serum-deprivation presents some cellular stress difficult to overcome by the KC stromal cells. Our study provides molecular insights into AKT and TGFβ signal changes in KC, and a mechanism for functional studies of stromal cells from KC corneas.     

Growth of Acinetobacter baumannii in pellicle enhanced the expression of potential virulence factors

Background

Interestingly, Acinetobacter baumannii presents an enhanced capacity to form biofilms (also named pellicles) at the air-liquid interface as compared to the other Acinetobacter species. This characteristic questions the contribution of this phenotype to an increased risk of clinical infections by this pathogen.

Methodology/Principal Findings

By a proteomic approach using 2-D gel electrophoresis-LC-MS/MS mass spectrometry, we compared the membrane protein patterns of A. baumannii 77, a pellicle-forming clinical isolate, grown in planktonic and in sessile modes. We identified 52 proteins with a differential expression, including 32 up-regulated and 20 down-regulated in the pellicle state. Several proteins, differentially expressed during pellicle development, were of particular interest. We determined the over-expression of four siderophore iron uptake systems including the acinetobactin and enterobactin receptors and confirmed that the development of this type of biofilm is promoted by ferric ions. Two over-expressed proteins, CarO and an OprD-homologue, putative carbapenem-resistance associated porins, would be involved in the transport of specific compounds, like ornithine, a biosynthesis precursor of a siderophore from the hydroxamate family. We evidenced the overexpression of a lipase and a transporter of LCFA that may be involved in the recycling of lipids inside the pellicle matrix. Finally, we demonstrated both by proteomic and by AFM studies that this particular type of biofilm required multiple pili systems to maintain this cohesive structure at the air-liquid interface; two of these systems have never been described in A. baumannii.

Conclusions/Significance

Our study demonstrated that several proteins, overexpressed at a late state of pellicle development, could be potentially involved in virulence processes. Therefore, regarding the number of potential virulence factors that are over-expressed in this growth mode, the pellicle-forming clinical isolates should be kept under survey.     

N-Terminal Domain of Turkey Pancreatic Lipase is Active on Long Chain Triacylglycerols and Stabilized by Colipase

The gene encoding the TPL N-terminal domain (N-TPL), fused with a His6-tag, was cloned and expressed in Pichia pastoris, under the control of the glyceraldehyde-3-phosphate dehydrogenase (GAP) constitutive promoter. The recombinant protein was successfully expressed and secreted with an expression level of 5 mg/l of culture medium after 2 days of culture. The N-TPL was purified through a one-step Ni-NTA affinity column with a purification factor of approximately 23-fold. The purified N-TPL, with a molecular mass of 35 kDa, had a specific activity of 70 U/mg on tributyrin. Surprisingly, this domain was able to hydrolyse long chain TG with a specific activity of 11 U/mg using olive oil as substrate. This result was confirmed by TLC analysis showing that the N-TPL was able to hydrolyse insoluble substrates as olive oil. N-TPL was unstable at temperatures over 37°C and lost 70% of its activity at acid pH, after 5 min of incubation. The N-TPL exhibited non linear kinetics, indicating its rapid denaturation at the tributyrin–water interface. Colipase increased the N-TPL stability at the lipid-water interface, so the TPL N-terminal domain probably formed functional interactions with colipase despite the absence of the C-terminal domain.     

The potential of <Emphasis Type="Italic">Rhizobium</Emphasis> strains for biological control of <Emphasis Type="Italic">Orobanche crenata</Emphasis>

Orobanche crenata Forsk is a chlorophyll lacking holoparasite that subsists on the roots of plants and causes significant damage to the culture of leguminous plants and, in particular, to peas (Pisum sativum L.). Here, we investigated the potential of Rhizobium strains for biological control of Orobanche crenata using a commercial pea cultivar (Douce de province) and different Rhizobium strains. Firstly, benefit of bacterial inoculation on plant growth and efficiency in N-incorporation were demonstrated with four isolates, P.SOM, P.1001, P.Mat.95 and P.1236. After five Rhizobium strains (three efficient: P.SOM, P.1236, P.Mat.95 and two not efficient: P.OM1.92, P.MleTem.92) were investigated for their ability to control Orobanche crenata using pot and Petri dish experiments. Inoculation of peas with two (P.SOM and P.1236) of the five strains induced a significant decrease in O. crenata seed germination and in the number of tubercles on pea roots. Furthermore, other symptoms, including the non-penetration of the germinated seeds into pea roots followed by radicle browning and death of the parasites, were observed in the presence of these inoculated pea plants. The hypothesis that roots secrete toxic compounds related to Rhizobium inoculation is discussed.     

Reproductive potential of balsam fir (Abies balsamea), white spruce (Picea glauca), and black spruce (P. mariana) at the ecotone between mixedwood and coniferous forests in the boreal zone of western Quebec

The reproductive potentials of balsam fir and white spruce (co-dominants in mixedwood forests) and black spruce (dominant in coniferous forests) were studied to explain the location of the ecotone between the two forest types in the boreal zone of Quebec. Four sites were selected along a latitudinal gradient crossing the ecotone. Cone crop, number of seeds per cone, percentage filled seeds, and percentage germination were measured for each species. Balsam fir and white spruce cone crops were significantly lower in the coniferous than in the mixedwood forest, while black spruce had greater crop constancy and regularity between both forest types. Mast years were more frequent for black spruce than for balsam fir in both forest types (mast year data not available for white spruce). The number of seeds per cone was more related to cone size than to forest type for all species. Black spruce produced more filled seeds in the coniferous forest than balsam fir or white spruce. The sum of growing degree-days and the maximum temperature of the warmest month (both for the year prior to cone production) significantly affected balsam fir cone production. The climate-related northward decrease in reproductive potential of balsam fir and white spruce could partly explain the position of the northern limit of the mixedwood forest. This could change drastically, however, as the ongoing climate warming might cancel this competitive advantage of black spruce.     

Increased constitutive αSMA and Smad2/3 expression in idiopathic pulmonary fibrosis myofibroblasts is KCa3.1-dependent

Background

Idiopathic pulmonary fibrosis is a common and invariably fatal disease with limited therapeutic options. Ca²⁺-activated K_Ca3.1 potassium channels play a key role in promoting TGFβ1 and bFGF-dependent profibrotic responses in human lung myofibroblasts (HLMFs). We hypothesised that K_Ca3.1 channel-dependent cell processes regulate HLMF αSMA expression via Smad2/3 signalling pathways.

Methods

In this study we have compared the phenotype of HLMFs derived from non-fibrotic healthy control lungs (NFC) with cells derived from IPF lungs. HLMFs grown in vitro were examined for αSMA expression by immunofluorescence (IF), RT-PCR and flow cytommetry. Basal Smad2/3 signalling was examined by RT-PCR, western blot and immunofluorescence. Two specific and distinct K_Ca3.1 blockers (TRAM-34 200 nM and ICA-17043 [Senicapoc] 100 nM) were used to determine their effects on HLMF differentiation and the Smad2/3 signalling pathways.

Results

IPF-derived HLMFs demonstrated increased constitutive expression of both α-smooth muscle actin (αSMA) and actin stress fibres, indicative of greater myofibroblast differentiation. This was associated with increased constitutive Smad2/3 mRNA and protein expression, and increased Smad2/3 nuclear localisation. The increased Smad2/3 nuclear localisation was inhibited by removing extracellular Ca²⁺ or blocking K_Ca3.1 ion channels with selective K_Ca3.1 blockers (TRAM-34, ICA-17043). This was accompanied by de-differentiation of IPF-derived HLMFs towards a quiescent fibroblast phenotype as demonstrated by reduced αSMA expression and reduced actin stress fibre formation.

Conclusions

Taken together, these data suggest that Ca²⁺- and K_Ca3.1-dependent processes facilitate “constitutive” Smad2/3 signalling in IPF-derived fibroblasts, and thus promote fibroblast to myofibroblast differentiation. Importantly, inhibiting K_Ca3.1 channels reverses this process. Targeting K_Ca3.1 may therefore provide a novel and effective approach for the treatment of IPF and there is the potential for the rapid translation of K_Ca3.1-directed therapy to the clinic.     

Epidemiology of Tick-Borne Borreliosis in Morocco

Background

The presence in Morocco of Argasid ticks of the Ornithodoros erraticus complex, the vector of tick-borne relapsing fever (TBRF) in North Africa, has been known since 1919, but the disease is rarely diagnosed and few epidemiological data are available.

Methodology/Principal Findings

Between 2006 and 2011, we investigated the presence of Ornithodoros ticks in rodent burrows in 34 sites distributed across Morocco. We also collected small mammals in 10 sites and we investigated TBRF in febrile patients in Kenitra district. The prevalence of Borrelia infections was assessed by nested PCR amplification in ticks and the brain tissue of small mammals, and by evaluation of thick blood films in patients. A high proportion of burrows were infested with ticks of the O. erraticus complex in all regions of Morocco, with a mean of 39.5% for the whole country. Borrelia infections were found in 39/382 (10.2%) of the ticks and 12/140 (8.6%) of the rodents and insectivores studied by PCR amplification, and 102 patients tested positive by thick blood film. Five small mammalian species were found infected: Dipodillus campestris, Meriones shawi, Gerbillus hoogstrali, Gerbillus occiduus and Atelerix algirus. Three Borrelia species were identified in ticks and/or rodents: B. hispanica, B. crocidurae and B. merionesi.

Conclusions/Significance

Tick populations belonging to O. erraticus complex are widely distributed in Morocco and a high proportion of ticks and small mammals are infected by Borrelia species. Although rarely diagnosed, TBRF may be a common cause of morbidity in all regions of Morocco.     

Improvement of Cerebellum Redox States and Cholinergic Functions Contribute to the Beneficial Effects of Silymarin Against Manganese-Induced Neurotoxicity

Manganese (Mn) is a potent neurotoxin involved in the initiation and progression of various cognitive disorders. Oxidative stress is reported as one of accepted mechanisms of Mn toxicity. The present study was designed to explore the effects of silymarin, a natural antioxidant, in attenuating the toxicity induced by Mn in rat cerebellum. In this investigation, rats were treated orally with MnCl₂ (20 mg/ml) for 30 days, subsets of these animals were treated intraperitoneally daily with silymarin (100 mg/kg) along with respective controls. Mn exposure caused a marked oxidative stress in cerebellum as indicated by a significant decrease in the activities of enzymatic antioxidants like superoxide dismutase, catalase and glutathione peroxidase and in the levels of non-enzymatic antioxidants like reduced glutathione (GSH), total thiols and vitamin C. Conversely an increase was obtained in lipid and protein markers such as thiobarbituric reactive acid substances, lipid hydroperoxide and protein carbonyl products contents. A Significant increase in acetylcholinesterase and a decrease in Na⁺/K⁺-ATPase activities were also shown, with a substantial rise in the expression of acetylcholinesterase and inducible nitric oxide synthase (iNOS), and nitric oxide levels. The potential effect of SIL to prevent Mn induced neurotoxicity was also reflected by histopathological observations. Rats exposed to Mn showed a reduced number and morphological alterations of cerebellar Purkinje cells. These phenomenons were completely reversed by SIL co-treatment. We concluded that silymarin may protect against Mn-induced oxidative stress in cerebellum by inhibiting both lipid and protein oxidation and by activating acetylcholinesterase and inducible nitric oxide synthase (iNOS) gene expression.     

Resting regulatory CD4 T cells: a site of HIV persistence in patients on long-term effective antiretroviral therapy

Background

In HIV-infected patients on long-term HAART, virus persistence in resting long-lived CD4 T cells is a major barrier to curing the infection. Cell quiescence, by favouring HIV latency, reduces the risk of recognition and cell destruction by cytotoxic lymphocytes. Several cell-activation-based approaches have been proposed to disrupt cell quiescence and then virus latency, but these approaches have not eradicated the virus. CD4⁺CD25⁺ regulatory T cells (Tregs) are a CD4⁺ T-cell subset with particular activation properties. We investigated the role of these cells in virus persistence in patients on long-term HAART.

Methodology/Principal Findings

We found evidence of infection of resting Tregs (HLADR⁻CD69⁻CD25^hiFoxP3⁺CD4⁺ T cells) purified from patients on prolonged HAART. HIV DNA harbouring cells appear more abundant in the Treg subset than in non-Tregs. The half-life of the Treg reservoir was estimated at 20 months. Since Tregs from patients on prolonged HAART showed hyporesponsiveness to cell activation and inhibition of HIV-specific cytotoxic T lymphocyte-related functions upon activation, therapeutics targeting cell quiescence to induce virus expression may not be appropriate for purging the Treg reservoir.

Conclusions

Our results identify Tregs as a particular compartment within the latent reservoir that may require a specific approach for its purging.     

The effect of combining HIIT and dry-land training on strength,technique, and 100-m butterfly swimming performance in age-group swimmers: a randomized controlled trial

Combined interventions of pool-based and dry-land workouts are a common practice in swimming training. However, the effects on strength, technique and swimming performance are still not clear. Through a randomized controlled trial study, we investigated the effect of combining high intensity interval training (HIIT) and maximum strength training (MST) on strength, technique and 100-m butterfly swimming performance. Competitive age-group swimmers (N = 22, males) were randomly divided into two groups. The experimental group (EG: 14.1 ± 0.3 years old) performed 8 weeks of combined short-moderate HIIT and MST. The control group (CG: 14.5 ± 0.3 years old) subjects performed their usual training. Muscular strength, technique and swimming performance were evaluated before and after 8 weeks. Substantial improvements were observed in maximum muscle strength (mean diff: 22–28%; p < 0.001; d = 3.25–3.61), technique (p < 0.05; d = 0.98–1.96) and 100-m butterfly swimming performance (3.5%; p = 0.001; d = 1.81) when combining HIIT and MST during 8 weeks. Combining short-moderate HIIT and MST during 8 weeks can enhance maximum muscular strength, technique, and 100-m butterfly swimming performance. Coaches should adjust training programmes accordingly since it could yield important differences in swimming performance during competitions.