Building the foundation for a modern patient-partnered infrastructure to study temporomandibular disorders.

Background: Conflicting reports from varying stakeholders related to prognosis and outcomes following placement of temporomandibular joint (TMJ) implants gave rise to the development of the TMJ Patient-Led RoundTable initiative. Following an assessment of the current availability of data, the RoundTable concluded that a strategically Coordinated Registry Network (CRN) is needed to collect and generate accessible data on temporomandibular disorder (TMD) and its care. The aim of this study was therefore to advance the clinical understanding, usage, and adoption of a core minimum dataset for TMD patients as the first foundational step toward building the CRN. Methods: Candidate data elements were extracted from existing data sources and included in a Delphi survey administered to 92 participants. Data elements receiving less than 75% consensus were dropped. A purposive multi-stakeholder sub-group triangulated the items across patient and clinician-based experience to remove redundancies or duplicate items and reduce the response burden for both patients and clinicians. To reliably collect the identified data elements, the identified core minimum data elements were defined in the context of technical implementation within High-performance Integrated Virtual Environment (HIVE) web-application framework. HIVE was integrated with CHIOS™, an innovative permissioned blockchain platform, to strengthen the provenance of data captured in the registry and drive metadata to record all registry transaction and create a robust consent network. Results: A total of 59 multi-stakeholder participants responded to the Delphi survey. The completion of the Delphi surveys followed by the application of the required group consensus threshold resulted in the selection of 397 data elements (254 for patient-generated data elements and 143 for clinician generated data elements). The infrastructure development and integration of HIVE and CHIOS™ was completed showing the maintenance of all data transaction information in blockchain, flexible recording of patient consent, data cataloging, and consent validation through smart contracts. Conclusion: The identified data elements and development of the technological platform establishes a data infrastructure that facilitates the standardization and harmonization of data as well as perform high performance analytics needed to fully leverage the captured patient-generated data, clinical evidence, and other healthcare ecosystem data within the TMJ/TMD-CRN.

A tough trek in the development of an anti-amyloid therapy for Alzheimer's disease: Do we see hope in the distance?

The search for a clinically effective therapy for patients with Alzheimer's disease (AD) has been long and arduous. In some circles the recent US Food and Drug Administration (FDA) approval of the human monoclonal antibody, Aducanumab, was viewed as a welcome advance. However, the administrative decision, in the face of a negative review by the members of the FDA neurology advisory board raised many questions concerning its appropriateness. In response the FDA has modified the conditions under which the drug should be administered. Currently, the etiology of AD remains unknown. Thus, application of therapies based on the still controversial amyloid hypothesis deserves critical scrutiny. While successful animal studies based on the hypothesis have stimulated many clinical trials in humans, none of these have shown statistically clinical benefit, raising questions regarding the intrinsic validity of the hypothesis itself. However, each successive trial has benefited from the experiences of those which preceded it. Given these caveats, the relevance of an apparent beneficial response in a subset of Aducanumab treated study participants must be weighed carefully. There are competing hypotheses regarding the etiology and pathophysiology responsible for the development of AD, including tau protein aggregation, acetylcholine deficiency, neuroinflammation, among others, all of which remain controversial. Nonetheless, the newly approved agent, Aducanumab did show some subtle benefit in some mild AD patients. Understanding the current hypotheses and controversies may help better evaluate the limitations and challenges in anti-amyloid therapy and in exploration of more efficacious therapies in treating patients with AD in the future.

Phosphorylation of p66Shc and forkhead proteins mediates Abeta toxicity.

Excessive accumulation of amyloid beta-peptide (Abeta) plays an early and critical role in synapse and neuronal loss in Alzheimer's Disease (AD). Increased oxidative stress is one of the mechanisms whereby Abeta induces neuronal death. Given the lessened susceptibility to oxidative stress exhibited by mice lacking p66Shc, we investigated the role of p66Shc in Abeta toxicity. Treatment of cells and primary neuronal cultures with Abeta caused apoptotic death and induced p66Shc phosphorylation at Ser36. Ectopic expression of a dominant-negative SEK1 mutant or chemical JNK inhibition reduced Abeta-induced JNK activation and p66Shc phosphorylation (Ser36), suggesting that JNK phosphorylates p66Shc. Abeta induced the phosphorylation and hence inactivation of forkhead transcription factors in a p66Shc-dependent manner. Ectopic expression of p66ShcS36A or antioxidant treatment protected cells against Abeta-induced death and reduced forkhead phosphorylation, suggesting that p66Shc phosphorylation critically influences the redox regulation of forkhead proteins and underlies Abeta toxicity. These findings underscore the potential usefulness of JNK, p66Shc, and forkhead proteins as therapeutic targets for AD.

Red cell perturbations by amyloid beta-protein.

Amyloid beta-protein (A beta) accumulation in brain is thought to be important in causing the neuropathology of Alzheimer's disease (AD). A beta interactions with both neurons and microglial cells play key roles in AD. Since vascular deposition of A beta is also implicated in AD, the interaction of red cells with these toxic aggregates gains importance. However, the effects of A beta interactions with red blood cells are less well understood. Synthetic amyloid beta-protein (1-40) was labeled with biotin and preincubated at 37 degrees C for 4, 14 and 72 h to produce fibrils. Flow cytometry was used to study the binding of these fibrils to red cells. The amyloid fibrils had a high affinity for the red cell with increased binding for the larger fibrils produced by longer preincubation. Bovine serum albumin (BSA) did not reverse the binding, but actually resulted in a more efficient binding of the A beta fibrils to the red cells. The interaction of A beta with red cells increased the mean cell volume and caused the cells to become more spherical. This effect was greater for the longer fibrils. At the same time the interaction of A beta with red cells produced an increase in their fluorescence measured after 16-h incubation at 37 degrees C. This increase in fluorescence is attributed to the formation of fluorescent heme degradation products. The effect of prior hemoglobin oxidation, catalase inhibition and glutathione peroxidase inhibition indicated that the amyloid-induced oxidative damage to the red cell involved hydrogen peroxide-induced heme degradation. These results suggest that amyloid interactions with the red cell may contribute to the pathology of AD.

Enhanced Aß(1-40) production in endothelial cells stimulated with fibrillar Aß(1-42).

Amyloid accumulation in the brain of Alzheimer's patients results from altered processing of the 39- to 43-amino acid amyloid ß protein (Aß). The mechanisms for the elevated amyloid (Aß(1-42)) are considered to be over-expression of the amyloid precursor protein (APP), enhanced cleavage of APP to Aß, and decreased clearance of Aß from the central nervous system (CNS). We report herein studies of Aß stimulated effects on endothelial cells. We observe an interesting and as yet unprecedented feedback effect involving Aß(1-42) fibril-induced synthesis of APP by Western blot analysis in the endothelial cell line Hep-1. We further observe an increase in the expression of Aß(1-40) by flow cytometry and fluorescence microscopy. This phenomenon is reproducible for cultures grown both in the presence and absence of serum. In the former case, flow cytometry reveals that Aß(1-40) accumulation is less pronounced than under serum-free conditions. Immunofluorescence staining further corroborates these observations. Cellular responses to fibrillar Aß(1-42) treatment involving eNOS upregulation and increased autophagy are also reported.

Signaling mechanisms underlying Abeta toxicity: potential therapeutic targets for Alzheimer's disease.

The accumulation of amyloid beta peptide (Abeta) is believed to be an early and critical event leading to synapse and neuronal cell loss in Alzheimer's Disease (AD). Abeta itself is toxic to neurons in vitro and the load of Abeta in vivo causes the loss of synapses and neurons in brain in animal models. Therefore, there has been considerable interest in elucidating the mechanism(s) of Abeta neurotoxicity. Here, we review the molecular signaling pathways involved in Abeta-induced cell death, including signaling through the neuronal nicotinic receptor and the Abeta-triggered generation of reactive oxygen species (ROS) leading to the activation of the c-jun N-terminal kinase (JNK), and the ensuing phosphorylation of p66Shc and inactivation of the Forkhead transcription factors. This focused review not only provides a better understanding of the signaling mechanisms involved in Abeta-induced cell death, but also underscores the potential of JNK, p66Shc, Forkhead proteins, p25/cdk5, and neuronal nicotinic receptor, as therapeutic targets for AD.

Signaling events in amyloid beta-peptide-induced neuronal death and insulin-like growth factor I protection.

Amyloid beta-peptide (Abeta) is implicated as the toxic agent in Alzheimer's disease and is the major component of brain amyloid plaques. In vitro, Abeta causes cell death, but the molecular mechanisms are unclear. We analyzed the early signaling mechanisms involved in Abeta toxicity using the SH-SY5Y neuroblastoma cell line. Abeta caused cell death and induced a 2- to 3-fold activation of JNK. JNK activation and cell death were inhibited by overexpression of a dominant-negative SEK1 (SEK1-AL) construct. Butyrolactone I, a cdk5 inhibitor, had an additional protective effect against Abeta toxicity in these SEK1-AL-expressing cells suggesting that cdk5 and JNK activation independently contributed to this toxicity. Abeta also weakly activated ERK and Akt but had no effect on p38 kinase. Inhibitors of ERK and phosphoinositide 3-kinase (PI3K) pathways did not affect Abeta-induced cell death, suggesting that these pathways were not important in Abeta toxicity. Insulin-like growth factor I protected against Abeta toxicity by strongly activating ERK and Akt and blocking JNK activation in a PI3K-dependent manner. Pertussis toxin also blocked Abeta-induced cell death and JNK activation suggesting that G(i/o) proteins were upstream activators of JNK. The results suggest that activation of the JNK pathway and cdk5 may be initial signaling cascades in Abeta-induced cell death.

Abeta 17-42 in Alzheimer's disease activates JNK and caspase-8 leading to neuronal apoptosis.

The p3 peptide [amyloid beta-peptide (Abeta) 17-40/42], derived by alpha- and gamma-secretase cleavage of the amyloid precursor protein (APP), is a major constituent of diffuse plaques in Alzheimer's disease and cerebellar pre-amyloid in Down's syndrome. However, the importance of p3 peptide accumulation in Alzheimer's disease and its toxic properties is not clear. Here, we demonstrate that treatment of cells with Abeta 17-42 leads to apoptosis in two human neuroblastoma cell lines, SH-SY5Y and IMR-32. Abeta 17-42 activated caspase-8 and caspase-3, induced poly(ADP-ribose) polymerase cleavage, but did not activate caspase-9. Selective caspase-8 and caspase-3 inhibitors completely blocked Abeta 17-42-induced neuronal death. Abeta 17-42 moderately activated c-Jun N-terminal kinase (JNK); however, overexpression of a dominant-negative mutant of SEK1, the upstream kinase of JNK, protected against Abeta 17-42 induced neuronal death. These results demonstrate that Abeta 17-42 induced neuronal apoptosis via a Fas-like/caspase-8 activation pathway. Our findings reveal the previously unrecognized toxic effect of Abeta 17-42. We propose that Abeta 17-42 constitutes an additional toxic peptide derived from APP proteolysis and may thus contribute to the neuronal cell loss characteristic of Alzheimer's disease.