Plant cells have developed specific protective molecular machinery against environmental stresses. The family of CBL-interacting protein kinases (CIPK) and their interacting activators, the calcium ...sensors calcineurin B-like (CBLs), work together to decode calcium signals elicited by stress situations. The molecular basis of biological activation of CIPKs relies on the calcium-dependent interaction of a self-inhibitory NAF motif with a particular CBL, the phosphorylation of the activation loop by upstream kinases, and the subsequent phosphorylation of the CBL by the CIPK. We present the crystal structures of the NAF-truncated and pseudophosphorylated kinase domains of CIPK23 and CIPK24/SOS2. In addition, we provide biochemical data showing that although CIPK23 is intrinsically inactive and requires an external stimulation, CIPK24/SOS2 displays basal activity. This data correlates well with the observed conformation of the respective activation loops: Although the loop of CIPK23 is folded into a well-ordered structure that blocks the active site access to substrates, the loop of CIPK24/SOS2 protrudes out of the active site and allows catalysis. These structures together with biochemical and biophysical data show that CIPK kinase activity necessarily requires the coordinated releases of the activation loop from the active site and of the NAF motif from the nucleotide-binding site. Taken all together, we postulate the basis for a conserved calcium-dependent NAF-mediated regulation of CIPKs and a variable regulation by upstream kinases.
Significance The transport of ions through the plant cell membrane establishes the key physicochemical parameters for cell function. Stress situations such as those created by soil salinity or low potassium conditions alter the ion transport across the membrane producing dramatic changes in the cell turgor, the membrane potential, and the intracellular pH and concentrations of toxic cations such as sodium and lithium. As a consequence, fundamental metabolic routes are inhibited. The CIPK family of 26 protein kinases regulates the function of several ion transporters at the cell membrane to restore ion homeostasis under stress situations. Our analyses provide an explanation on how the CIPKs are differentially activated to coordinate the adequate cell response to a particular stress.
Plant growth largely depends on the maintenance of adequate intracellular levels of potassium (K
). The families of 10 Calcineurin B-Like (CBL) calcium sensors and 26 CBL-Interacting Protein Kinases ...(CIPKs) of Arabidopsis (
) decode the calcium signals elicited by environmental inputs to regulate different ion channels and transporters involved in the control of K
fluxes by phosphorylation-dependent and -independent events. However, the detailed molecular mechanisms governing target specificity require investigation. Here, we show that the physical interaction between CIPK23 and the noncanonical ankyrin domain in the cytosolic side of the inward-rectifier K
channel AKT1 regulates kinase docking and channel activation. Point mutations on this domain specifically alter binding to CIPK23, enhancing or impairing the ability of CIPK23 to regulate channel activity. Our data demonstrate the relevance of this protein-protein interaction that contributes to the formation of a complex between CIPK23/CBL1 and AKT1 in the membrane for the proper regulation of K
transport.
Haploinsufficiency of the SLC2A1 gene and paucity of its translated product, the glucose transporter-1 (Glut1) protein, disrupt brain function and cause the neurodevelopmental disorder, Glut1 ...deficiency syndrome (Glut1 DS). There is little to suggest how reduced Glut1 causes cognitive dysfunction and no optimal treatment for Glut1 DS. We used model mice to demonstrate that low Glut1 protein arrests cerebral angiogenesis, resulting in a profound diminution of the brain microvasculature without compromising the blood-brain barrier. Studies to define the temporal requirements for Glut1 reveal that pre-symptomatic, AAV9-mediated repletion of the protein averts brain microvasculature defects and prevents disease, whereas augmenting the protein late, during adulthood, is devoid of benefit. Still, treatment following symptom onset can be effective; Glut1 repletion in early-symptomatic mutants that have experienced sustained periods of low brain glucose nevertheless restores the cerebral microvasculature and ameliorates disease. Timely Glut1 repletion may thus constitute an effective treatment for Glut1 DS.
Ischemic heart disease (IHD) and type-2 diabetes mellitus (T2DM) remain major health problems worldwide and commonly coexist in individuals. Gut microbial metabolites, such as trimethylamine N-oxide ...(TMAO) and short-chain fatty acids (SCFAs), have been linked to cardiovascular and metabolic diseases. Previous studies have reported dysbiosis in the gut microbiota of these patients and the prebiotic effects of some components of the Mediterranean diet. Essential oil emulsions of savory (Satureja hortensis), parsley (Petroselinum crispum) and rosemary (Rosmarinus officinalis) were assessed as nutraceuticals and prebiotics in IHD and T2DM. Humanized mice harboring gut microbiota derived from that of patients with IHD and T2DM were supplemented with L-carnitine and orally treated with essential oil emulsions for 40 days. We assessed the effects on gut microbiota composition and abundance, microbial metabolites and plasma markers of cardiovascular disease, inflammation and oxidative stress. Our results showed that essential oil emulsions in mice supplemented with L-carnitine have prebiotic effects on beneficial commensal bacteria, mainly Lactobacillus genus. There was a decrease in plasma TMAO and an increase in fecal SCFAs levels in mice treated with parsley and rosemary essential oils. Thrombomodulin levels were increased in mice treated with savory and parsley essential oils. While mice treated with parsley and rosemary essential oils showed a decrease in plasma cytokines (INFɣ, TNFα, IL-12p70 and IL-22); savory essential oil was associated with increased levels of chemokines (CXCL1, CCL2 and CCL11). Finally, there was a decrease in protein carbonyls and pentosidine according to the essential oil emulsion. These results suggest that changes in the gut microbiota induced by essential oils of parsley, savory and rosemary as prebiotics could differentially regulate cardiovascular and metabolic factors, which highlights the potential of these nutraceuticals for reducing IHD risk in patients affected by T2DM.
Alcoholic hepatitis is a severe complication of alcoholism, associated with high short-term mortality. Although pathogenesis remains obscure, it is generally accepted that lipopolysaccharide-induced ...cytokine secretion with further generation of reactive oxygen species (ROS) play outstanding roles. Prognosis is uncertain, and the usually employed prognostic scores do not include variables related to ROS generation. Therefore, this study was performed to assess short-term prognostic value of cytokines, nutritional status, different scores Maddrey, model for end-stage liver disease (MELD), albumin, bilirubin, INR, creatinine index (ABIC), Lille, Glasgow, MELD-Na, Child-Pugh and malondialdehyde (MDA, as an indicator of lipid peroxidation) at admission and after 1 week, among patients affected by severe acute alcoholic hepatitis (Maddrey index >32).
Sixty-two patients affected by severe acute alcoholic hepatitis, for whom we calculated Maddrey, MELD, ABIC, Lille, Glasgow, MELD-Na, Child-Pugh, and determined serum MDA and interleukin (IL)-6, IL-8, IL-4, tumor necrosis factor alpha and interferon gamma levels at admission and after 1 week.
Twenty-four patients died during the follow-up period. MDA showed a better prognostic accuracy than the aforementioned scores, both at admission and after 1 week.
Our study supports the importance of including MDA assessment in the prognostic evaluation of patients with alcoholic hepatitis.
Alcoholic hepatitis is associated with high short-term mortality. Although not included in prognostic scores, lipid peroxidation plays an outstanding role in its pathogenesis. We found that malondialdehyde levels showed a better prognostic accuracy than the usually employed scores. Therefore, it should be included in the prognostic evaluation of these patients.
Klebsiella aerogenes has been reclassified from Enterobacter to Klebsiella genus due to its phenotypic and genotypic similarities with Klebsiella pneumoniae. It is unclear if clinical outcomes are ...also more similar. This study aims to assess clinical outcomes of bloodstreams infections (BSI) caused by K. aerogenes, K. pneumoniae and Enterobacter cloacae, through secondary data analysis, nested in PRO-BAC cohort study.
Hospitalized patients between October 2016 and March 2017 with monomicrobial BSI due to K. aerogenes, K. pneumoniae or E. cloacae were included. Primary outcome was a composite clinical outcome including all-cause mortality or recurrence until 30 days follow-up. Secondary outcomes were fever ≥ 72 h, persistent bacteraemia, and secondary device infection. Multilevel mixed-effect Poisson regression was used to estimate the association between microorganisms and outcome.
Overall, 29 K. aerogenes, 77 E. cloacae and 337 K. pneumoniae BSI episodes were included. Mortality or recurrence was less frequent in K. aerogenes (6.9%) than in E. cloacae (20.8%) or K. pneumoniae (19.0%), but statistical difference was not observed (rate ratio (RR) 0.35, 95% CI 0.08 to 1.55; RR 0.42, 95% CI 0.10 to 1.71, respectively). Fever ≥ 72 h and device infection were more common in K. aerogenes group. In the multivariate analysis, adjusted for confounders (age, sex, BSI source, hospital ward, Charlson score and active antibiotic therapy), the estimates and direction of effect were similar to crude results.
Results suggest that BSI caused by K. aerogenes may have a better prognosis than E. cloacae or K. pneumoniae BSI.
Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The ...objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 66% were E. faecium and 25 34% E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 95% CI0.67 to 0.80. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score ≤ 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score.
Delayed-type hypersensitivity to glatiramer acetate is rare, and the underlying immunological mechanisms are not completely understood.
To study the immunologic response in 2 patients with multiple ...sclerosis who developed maculopapular exanthema related with the administration of glatiramer acetate.
The allergologic study included general blood tests, viral serologic tests, and skin tests (patch and intradermal tests). The immunologic study was performed in skin biopsy specimens by immunohistochemistry and in the peripheral blood by flow cytometry and the lymphocyte transformation test.
Skin test results were negative in both patients, and the diagnosis was confirmed by a drug provocation test. The evaluation of the acute phase showed an increase in the percentage of CD8 T lymphocytes (>50%) and the percentage of cells expressing skin-homing receptor (cutaneous lymphocyte-associated antigen) (>70%) and chemokine receptors (CCR4 and CXCR3) at T1. A positive proliferative response was observed in T lymphocytes (stimulation index SI = 3.5 in patient 1 and 3.59 in patient 2), especially the CD8(+) subpopulation (SI = 5.5 and 4.6 in patients 1 and 2, respectively), and NK lymphocytes (SI = 3.9 and 8.5 in patients 1 and 2, respectively) after glatiramer acetate stimulation.
This study demonstrates the important role of T(H)1 cells expressing skin-homing receptors in delayed-type hypersensitivity reactions to glatiramer acetate. A lymphocyte transformation test revealed a specific glatiramer acetate recognition by T lymphocytes and NK lymphocytes.
Mitochondria are key cellular organelles whose main function is maintaining cell bioenergetics by producing ATP through oxidative phosphorylation. However, mitochondria are involved in a much higher ...number of cellular processes. Mitochondria are the home of key metabolic pathways like the tricarboxylic acid cycle and β-oxidation of fatty acids, as well as biosynthetic pathways of key products like nucleotides and amino acids, the control of the redox balance of the cell and detoxifying the cell from H
S and NH
. This plethora of critical functions within the cell is the reason mitochondrial function is involved in several complex disorders (apart from pure mitochondrial disorders), among them inflammatory bowel diseases (IBD). IBD are a group of chronic, inflammatory disorders of the gut, mainly composed of ulcerative colitis and Crohn's disease. In this review, we present the current knowledge regarding the impact of mitochondrial dysfunction in the context of IBD. The role of mitochondria in both intestinal mucosa and immune cell populations are discussed, as well as the role of mitochondrial function in mechanisms like mucosal repair, the microbiota- and brain-gut axes and the development of colitis-associated colorectal cancer.
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