Role of cholinesterase inhibitors in Parkinson's disease and dementia with Lewy bodies

This article reviews the cholinergic changes in Parkinson's disease and dementia (PDD) and dementia with Lewy bodies (DLB), their potential clinical implications, and the available evidence for cholinesterase inhibitors in the treatment of PDD and DLB. Marked neuronal loss of cholinergic nuclei, reduced cholinergic markers in the neocortex, hippocampus, and selected thalamic nuclei, and receptor changes have been reported. One large and 2 small placebo-controlled trials and nearly 20 open-label studies suggest that cholinesterase inhibitors have a positive effect on cognition, psychiatric symptoms, and global function in patients with DLB and PDD. The treatment is well tolerated in most patients without any apparent worsening of extrapyramidal motor features. Given the high risk of severe sensitivity reactions and increased risk of cerebrovascular incidents during treatment with neuroleptics, more clinical trials of cholinesterase inhibitors are encouraged to establish their precise role in DLB and PDD.

Combination of Psychological Intervention and Phosphodiesterase-5 Inhibitors for Erectile Dysfunction: A Narrative Review and Meta-Analysis

INTRODUCTION Erectile dysfunction (ED) is an increasing health problem that demands effective treatment. There is evidence that phosphodiesterase-5 inhibitors (PDE5-Is) and psychological intervention (PI) are effective treatment options; however, little is known about their comparative efficacy and the efficacy of combined treatments. AIM The aim of this systematic review and meta-analysis is to evaluate the comparative efficacy of PI, PDE5-Is, and their combination in the treatment of ED. MAIN OUTCOME MEASURES Primary outcome was ED symptoms, and secondary outcome was sexual satisfaction of the patient. METHODS A systematic literature search was conducted in order to identify relevant articles published between 1998 and 2012. We included randomized controlled trials and controlled trials comparing PI with PDE5-I treatment or one of them against a combination of both. RESULTS Eight studies with a total number of 562 patients were included in the meta-analysis. The results of the included studies are inconclusive, though they show a trend towards a larger effect of combined treatment compared with PI or PDE5-I treatment alone. The meta-analysis found that, overall, combined treatment was more efficacious for ED symptoms than PDE5-I treatment or PI alone. Combined treatment was more efficacious than PDE5-I use alone on sexual satisfaction. No differences were found between PDE5-Is and PI as stand-alone treatments. None of the moderators (treatment duration, methodological quality, or researcher allegiance) altered the effects. CONCLUSIONS The combination of PI and PDE5-Is is a promising strategy for a favorable outcome in ED and can be considered as a first-choice option for ED patients. Stronger RCTs are required to confirm this initial finding. Schmidt HM, Munder T, Gerger H, Frühauf S, and Barth J. Combination of psychological intervention and phosphodiesterase-5 inhibitors for erectile dysfunction: A narrative review and meta-analysis. J Sex Med **;**:**-**.

Characterization of Hsp70 binding and nucleotide exchange by the yeast Hsp110 chaperone Sse1.

SSE1 and SSE2 encode the essential yeast members of the Hsp70-related Hsp110 molecular chaperone family. Both mammalian Hsp110 and the Sse proteins functionally interact with cognate cytosolic Hsp70s as nucleotide exchange factors. We demonstrate here that Sse1 forms high-affinity (Kd approximately 10-8 M) heterodimeric complexes with both yeast Ssa and mammalian Hsp70 chaperones and that binding of ATP to Sse1 is required for binding to Hsp70s. Sse1.Hsp70 heterodimerization confers resistance to exogenously added protease, indicative of conformational changes in Sse1 resulting in a more compact structure. The nucleotide binding domains of both Sse1/2 and the Hsp70s dictate interaction specificity and are sufficient for mediating heterodimerization with no discernible contribution from the peptide binding domains. In support of a strongly conserved functional interaction between Hsp110 and Hsp70, Sse1 is shown to associate with and promote nucleotide exchange on human Hsp70. Nucleotide exchange activity by Sse1 is physiologically significant, as deletion of both SSE1 and the Ssa ATPase stimulatory protein YDJ1 is synthetically lethal. The Hsp110 family must therefore be considered an essential component of Hsp70 chaperone biology in the eukaryotic cell.

All in the family: atypical Hsp70 chaperones are conserved modulators of Hsp70 activity.

Divergent relatives of the Hsp70 protein chaperone such as the Hsp110 and Grp170 families have been recognized for some time, yet their biochemical roles remained elusive. Recent work has revealed that these "atypical" Hsp70s exist in stable complexes with classic Hsp70s where they exert a powerful nucleotide-exchange activity that synergizes with Hsp40/DnaJ-type cochaperones to dramatically accelerate Hsp70 nucleotide cycling. This represents a novel evolutionary transition from an independent protein-folding chaperone to what appears to be a dedicated cochaperone. Contributions of the atypical Hsp70s to established cellular roles for Hsp70 now must be deciphered.

Hsp110 chaperones control client fate determination in the hsp70-Hsp90 chaperone system.

Heat shock protein 70 (Hsp70) plays a central role in protein homeostasis and quality control in conjunction with other chaperone machines, including Hsp90. The Hsp110 chaperone Sse1 promotes Hsp90 activity in yeast, and functions as a nucleotide exchange factor (NEF) for cytosolic Hsp70, but the precise roles Sse1 plays in client maturation through the Hsp70-Hsp90 chaperone system are not fully understood. We find that upon pharmacological inhibition of Hsp90, a model protein kinase, Ste11DeltaN, is rapidly degraded, whereas heterologously expressed glucocorticoid receptor (GR) remains stable. Hsp70 binding and nucleotide exchange by Sse1 was required for GR maturation and signaling through endogenous Ste11, as well as to promote Ste11DeltaN degradation. Overexpression of another functional NEF partially compensated for loss of Sse1, whereas the paralog Sse2 fully restored GR maturation and Ste11DeltaN degradation. Sse1 was required for ubiquitinylation of Ste11DeltaN upon Hsp90 inhibition, providing a mechanistic explanation for its role in substrate degradation. Sse1/2 copurified with Hsp70 and other proteins comprising the "early-stage" Hsp90 complex, and was absent from "late-stage" Hsp90 complexes characterized by the presence of Sba1/p23. These findings support a model in which Hsp110 chaperones contribute significantly to the decision made by Hsp70 to fold or degrade a client protein.

Computational selection of inhibitors of Abeta aggregation and neuronal toxicity.

Alzheimer's disease (AD) is characterized by the cerebral accumulation of misfolded and aggregated amyloid-beta protein (Abeta). Disease symptoms can be alleviated, in vitro and in vivo, by 'beta-sheet breaker' pentapeptides that reduce plaque load. However the peptide nature of these compounds, made them biologically unstable and unable to penetrate membranes with high efficiency. The main goal of this study was to use computational methods to identify small molecule mimetics with better drug-like properties. For this purpose, the docked conformations of the active peptides were used to identify compounds with similar activities. A series of related beta-sheet breaker peptides were docked to solid state NMR structures of a fibrillar form of Abeta. The lowest energy conformations of the active peptides were used to design three dimensional (3D)-pharmacophores, suitable for screening the NCI database with Unity. Small molecular weight compounds with physicochemical features and a conformation similar to the active peptides were selected, ranked by docking and biochemical parameters. Of 16 diverse compounds selected for experimental screening, 2 prevented and reversed Abeta aggregation at 2-3microM concentration, as measured by Thioflavin T (ThT) fluorescence and ELISA assays. They also prevented the toxic effects of aggregated Abeta on neuroblastoma cells. Their low molecular weight and aqueous solubility makes them promising lead compounds for treating AD.

Impairment of rat postnatal lung alveolar development by glucocorticoids: involvement of the p21CIP1 and p27KIP1 cyclin-dependent kinase inhibitors

It has been shown that glucocorticoids accelerate lung development by limiting alveolar formation resulting from a premature maturation of the alveolar septa. Based on these data, the aim of the present work was to analyze the influence of dexamethasone on cell cycle control mechanisms during postnatal lung development. Cell proliferation is regulated by a network of signaling pathways that converge to the key regulator of cell cycle machinery: the cyclin-dependent kinase (CDK) system. The activity of the various cyclin/CDK complexes can be modulated by the levels of the cyclins and their CDKs, and by expression of specific CDK inhibitors (CKIs). In the present study, newborn rats were given a 4-d treatment with dexamethasone (0.1-0.01 microg/g body weight dexamethasone sodium phosphate daily on d 1-4), or saline. Morphologically, the treatment caused a significant thinning of the septa and an acceleration of lung maturation on d 4. Study of cyclin/CDK system at d 1-36 documented a transient down-regulation of cyclin/CDK complex activities at d 4 in the dexamethasone-treated animals. Analysis of the mechanisms involved suggested a role for the CKIs p21CIP1 and p27KIP1. Indeed, we observed an increase in p21CIP1 and p27KIP1 protein levels on d 4 in the dexamethasone-treated animals. By contrast, no variations in either cyclin and CDK expression, or cyclin/CDK complex formation could be documented. We conclude that glucocorticoids may accelerate lung maturation by influencing cell cycle control mechanisms, mainly through impairment of G1 cyclin/CDK complex activation.

Correlation of serum and urinary matrix metalloproteases/tissue inhibitors of metalloproteases with subclinical allograft fibrosis in renal transplantation

Progressive interstitial fibrosis and tubular atrophy (IF/TA) is a leading cause of chronic allograft dysfunction. Increased extracellular matrix remodeling regulated by matrix metalloproteases (MMPs) and their inhibitors (TIMPs) has been implicated in the development of IF/TA. The aim of this study was to investigate whether urinary/serum MMPs/TIMPs correlate with subclinical IF/TA detected in surveillance biopsies within the first 6months post-transplant. We measured eight different MMPs/TIMPs simultaneously in urine and serum samples from patients classified as normal histology (n=15), IF/TA 1 (n=15) and IF/TA 2-3 (n=10). There was no difference in urinary MMPs/TIMPs among the three groups, and only 1/8 serum MMPs/TIMPs (i.e. MMP-1) was significantly elevated in biopsies with IF/TA 2-3 (p=0.01). In addition, urinary/serum MMPs/TIMPs were not different between surveillance biopsies demonstrating an early development of IF/TA (i.e. delta IF/TA≥1 compared to a previous biopsy obtained three months before; n=11) and stable grade of IF/TA (i.e. delta IF/TA=0; n=20). Next, we investigated whether urinary/serum MMP/TIMP levels are elevated during acute subclinical tubulitis in surveillance biopsies obtained within the first 6months post-transplant (n=25). Compared to biopsies with normal histology, serum MMPs/TIMPs were not different; however, all urinary MMP/TIMP levels were numerically higher during subclinical tubulitis (MMP-1, MMP-7, TIMP-1 with p≤0.04). We conclude that urinary/serum MMPs/TIMPs do hardly correlate with existing or early developing IF/TA in surveillance biopsies obtained within the first 6months post-transplant. This could be explained by the dynamic process of extracellular matrix remodeling, which seems to be active during acute tubulo-interstitial injury/inflammation, but not in quiescent IF/TA.

Allograft Survival with Calcineurin Inhibitors

The immunosuppressive drugs cyclosporine A (CsA) and tacrolimus (FK506), also called calcineurin inhibitors, have truly revolutionized allograft transplantation. The introduction of CsA in 1976 was the first major advance in transplantation since the introduction of prednisone and azathioprine made allograft transplantation possible in the early 1950s and 1960s. FK506 was approved in 1994 and led to dramatic improvements in solid organ transplantation, allowing highly antigenic lymph node bearing allografts, such as the small bowel, to be transplanted. Recently, FK506 monotherapy has successfully allowed combined small bowel and partial abdominal wall transplantation in humans. The success of FK506 and CsA has made them key drugs in the modern era of transplantation. The purine synthesis inhibitor mycophenolate mofetil (MMF) was approved in 1995, and the drug Sirolimus (rapamycin) was introduced in 1999. Combining these drugs with calcineurin inhibitors has significantly reduced the incidence of acute rejection and improved solid organ allograft survival, with a reduction in adverse effects.