Reduced Number of Platelets During Intra-Aortic Balloon Pumping Counterpulsation Predicts Higher Cardiovascular Mortality After Device Removal in Association with Systemic Inflammation.

Thrombocytopenia is a frequent complication in patients requiring intra-aortic balloon pumping (IABP) counterpulsation. However, its prognostic impact has not been fully addressed. The objective of this study is to evaluate the impact of the change in the platelet number during IABP use on the prognosis after device removal.This is a retrospective observational study. Patients in the intensive cardiac care unit at three Juntendo University hospitals who underwent percutaneous implantation of IABP with or without veno-arterial extracorporeal membrane oxygenation (V-A ECMO), since 2012-2016, were enrolled in the study (n = 439). Patients who died during mechanical circulatory support (n = 47) were excluded. We evaluated the prognostic impact of the ratio of platelet reduction from the baseline (% PLT reduction) during IABP use on cardiovascular mortality after device removal.The median and the range of follow-up period were 298 days and 0-1,869 days, respectively. Unadjusted Kaplan-Meier analysis demonstrated that patients with a higher % PLT reduction had higher cardiovascular (CV) mortality. An adjusted Cox proportional hazard analysis demonstrated that a 10% higher % PLT reduction was associated with higher cardiovascular (CV) mortality (Hazard ratio: 1.3, 95% Confidence interval: 1.1-1.6, P < 0.001). Moreover, % PLT reduction and the maximum C-reactive protein (CRP) level during IABP use were positively correlated (r = 0.326, P < 0.001).The reduced number of platelets during IABP use was associated with an increased risk of CV mortality.

A Novel Nutritional Index Serves as A Useful Prognostic Indicator in Cardiac Critical Patients Requiring Mechanical Circulatory Support.

BACKGROUND: A poor nutritional status has been gathering intense clinical interest recently as it has been suggested to associate with adverse outcomes in patients in the intensive care unit (ICU). However, there is still no established nutritional index dominantly used in clinical practice. We have previously proposed a novel nutritional index, which can be calculated using serum levels of triglycerides, total cholesterol, and body weight (TCBI). In this study, to expand the application of TCBI for critical patients, we investigated the usefulness of TCBI to predict prognosis in hemodynamically unstable patients with percutaneously implantable mechanical circulatory support (MCS) devices in the ICU. PATIENTS AND METHODS: This is a retrospective analysis of a multicenter registry consisting of three Juntendo University hospitals in Japan involving patients who received MCS devices, including intra-aortic balloon pumping (IABP) with or without veno-arterial extracorporeal membrane oxygenation (VA-ECMO), between 2012 and 2016 (n = 439). The median follow-up period was 298 days. RESULTS: Spearman's correlation coefficient between TCBI and the geriatric nutritional risk index (GNRI) was 0.44 (p < 0.0001), indicating a moderate positive correlation for these two variables. Unadjusted Kaplan-Meier analysis demonstrated reduced risks of all-cause and cardiovascular mortalities in patients with higher tertiles of TCBI. Furthermore, adjusted multivariate Cox proportional hazard analyses revealed that the highest tertile TCBI was an independent predictor for the reduced risk of all-cause mortality (hazard ratio (HR): 0.22, 95% confidence interval: 0.10-0.48, p < 0.0001) and cardiovascular mortality (0.20, 0.09-0.45, p < 0.0001). CONCLUSION: A novel and simple to calculate nutritional index, TCBI, can be applicable as a prognostic indicator in hemodynamically unstable patients requiring MCS devices.

Minus end-directed motor KIFC3 suppresses E-cadherin degradation by recruiting USP47 to adherens junctions.

The adherens junction (AJ) plays a crucial role in maintaining cell-cell adhesion in epithelial tissues. Previous studies show that KIFC3, a minus end-directed kinesin motor, moves into AJs via microtubules that grow from clusters of CAMSAP3 (also known as Nezha), a protein that binds microtubule minus ends. The function of junction-associated KIFC3, however, remains to be elucidated. Here we find that KIFC3 binds the ubiquitin-specific protease USP47, a protease that removes ubiquitin chains from substrates and hence inhibits proteasome-mediated proteolysis, and recruits it to AJs. Depletion of KIFC3 or USP47 promotes cleavage of E-cadherin at a juxtamembrane region of the cytoplasmic domain, resulting in the production of a 90-kDa fragment and the internalization of E-cadherin. This cleavage depends on the E3 ubiquitin protein ligase Hakai and is inhibited by proteasome inhibitors. E-cadherin ubiquitination consistently increases after depletion of KIFC3 or USP47. These findings suggest that KIFC3 suppresses the ubiquitination and resultant degradation of E-cadherin by recruiting USP47 to AJs, a process that may be involved in maintaining stable cell-cell adhesion in epithelial sheets.

Tumor necrosis factor receptor-associated protein 1 regulates cell adhesion and synaptic morphology via modulation of N-cadherin expression.

An increase in serum tumor necrosis factor-alpha (TNF-alpha) levels is closely related to the pathogenesis of major depression. However, the underlying molecular mechanism between this increase and impairment of brain function remains elusive. To better understand TNF-alpha/TNF receptor 1 signaling in the brain, we analyzed the brain distribution and function of tumor necrosis factor receptor-associated protein 1 (TRAP1). Here we show that TRAP1 is broadly expressed in neurons in the mouse brain, including regions that are implicated in the pathogenesis of major depression. We demonstrate that small interfering RNA-mediated knockdown of TRAP1 in a neuronal cell line decreases tyrosine phosphorylation of STAT3, followed by a reduction of the transcription factor E2F1, resulting in a down-regulation of N-cadherin, and affects the adhesive properties of the cells. In addition, in cultured hippocampal neurons, reduced expression of N-cadherin by TRAP1 knockdown influences the morphology of dendritic spines. We also report a significant association between several single nucleotide polymorphisms in the TRAP1 gene and major depression. Our findings indicate that TRAP1 mediates TNF-alpha/TNF receptor 1 signaling to modulate N-cadherin expression and to regulate cell adhesion and synaptic morphology, which may contribute to the pathogenesis of major depression.

Dysbindin engages in c-Jun N-terminal kinase activity and cytoskeletal organization.

A number of reports have provided genetic evidence for an association between the DTNBP1 gene (coding dysbindin) and schizophrenia. In addition, sandy mice, which harbor a deletion in the DTNBP1 gene and lack dysbindin, display behavioral abnormalities suggestive of an association with schizophrenia. However, the mechanism by which the loss of dysbindin induces schizophrenia-like behaviors remains unclear. Here, we report that small interfering RNA-mediated knockdown of dysbindin resulted in the aberrant organization of actin cytoskeleton in SH-SY5Y cells. Furthermore, we show that morphological abnormalities of the actin cytoskeleton were similarly observed in growth cones of cultured hippocampal neurons derived from sandy mice. Moreover, we report a significant correlation between dysbindin expression level and the phosphorylation level of c-Jun N-terminal kinase (JNK), which is implicated in the regulation of cytoskeletal organization. These findings suggest that dysbindin plays a key role in coordinating JNK signaling and actin cytoskeleton required for neural development.

A ubiquitin ligase HRD1 promotes the degradation of Pael receptor, a substrate of Parkin.

It has been proposed that in autosomal recessive juvenile parkinsonism (AR-JP), a ubiquitin ligase (E3) Parkin, which is involved in endoplasmic reticulum-associated degradation (ERAD), lacks E3 activity. The resulting accumulation of Parkin-associated endothelin receptor-like receptor (Pael-R), a substrate of Parkin, leads to endoplasmic reticulum stress, causing neuronal death. We previously reported that human E3 HRD1 in the endoplasmic reticulum protects against endoplasmic reticulum stress-induced apoptosis. This study shows that HRD1 was expressed in substantia nigra pars compacta (SNC) dopaminergic neurons and interacted with Pael-R through the HRD1 proline-rich region, promoting the ubiquitylation and degradation of Pael-R. Furthermore, the disruption of endogenous HRD1 by small interfering RNA (siRNA) induced Pael-R accumulation and caspase-3 activation. We also found that ATF6 overexpression, which induced HRD1, accelerated and caused Pael-R degradation; the suppression of HRD1 expression by siRNA partially prevents this degradation. These results suggest that in addition to Parkin, HRD1 is also involved in the degradation of Pael-R.

Suppressive effects of 4-phenylbutyrate on the aggregation of Pael receptors and endoplasmic reticulum stress.

Endoplasmic reticulum (ER) stress is defined as an accumulation of unfolded proteins in the endoplasmic reticulum. 4-phenylbutyrate (4-PBA) has been demonstrated to promote the normal trafficking of the DeltaF508 cystic fibrosis transmembrane conductance regulator (CFTR) mutant from the ER to the plasma membrane and to restore activity. We have reported that 4-PBA protected against cerebral ischemic injury and ER stress-induced neuronal cell death. In this study, we revealed that 4-PBA possesses chemical chaperone activity in vitro, which prevents the aggregation of denatured alpha-lactalbumin and bovine serum albumin (BSA). Furthermore, we investigated the effects of 4-PBA on the accumulation of Parkin-associated endothelin receptor-like receptor (Pael-R) pathologically relevant to the loss of dopaminergic neurons in autosomal recessive juvenile parkinsonism (AR-JP). Interestingly, 4-PBA restored the normal expression of Pael-R protein and suppressed ER stress induced by the overexpression of Pael-R. In addition, we showed that 4-PBA attenuated the activation of ER stress-induced signal transduction pathways and subsequent neuronal cell death. Moreover, 4-PBA restored the viability of yeasts that fail to induce an ER stress response under ER stress conditions. These results suggest that 4-PBA suppresses ER stress by directly reducing the amount of misfolded protein, including Pael-R accumulated in the ER.