Most cases of Alzheimer's disease (AD) are sporadic, but a small percentage of AD cases, called familial AD (FAD), are associated with mutations in presenilin 1, presenilin 2, or the amyloid precursor protein. Amyloid precursor protein mutations falling within the amyloid-β (Aβ) sequence lead to a wide range of disease phenotypes. There is increasing evidence that distinct amyloid structures distinguished by amyloid conformation-dependent monoclonal antibodies have similarly distinct roles in pathology. It is possible that this phenotypic diversity of FAD associated with mutations within the Aβ sequence is due to differences in the conformations adopted by mutant Aβ peptides, but the effects of FAD mutations on aggregation kinetics and conformational and morphological changes of the Aβ peptide are poorly defined. To gain more insight into this possibility, we therefore investigated the effects of 11 FAD mutations on the aggregation kinetics of Aβ, as well as its ability to form distinct conformations recognized by a panel of amyloid conformation-specific monoclonal antibodies. We found that most FAD mutations increased the rate of aggregation of Aβ. The FAD mutations also led to the adoption of alternative amyloid conformations distinguished by monoclonal antibodies and resulted in the formation of distinct aggregate morphologies as determined by transmission electron microscopy. In addition, several of the mutant peptides displayed a large reduction in thioflavin T fluorescence, despite forming abundant fibrils indicating that thioflavin T is a probe of conformational polymorphisms rather than a reliable indicator of fibrillization. Taken together, these results indicate that FAD mutations falling within the Aβ sequence lead to dramatic changes in aggregation kinetics and influence the ability of Aβ to form immunologically and morphologically distinct amyloid structures.

Background: Several amyloid proteins form conformationally distinct aggregates. Results: 23 antibodies raised against fibrillar A␤42 display 18 unique reactivity profiles. Conclusion:The immune response to fibrillar amyloid reflects the diversity in amyloid structures. Significance: The use of a single antibody in immunization therapies of Alzheimer disease may not be effective, as it is unable to target all structural variants of A␤.

Recently we reported that several monoclonal antibodies that recognize linear segments of amyloid-β (Aβ) also recognize amyloid fibrils, but not monomers of unrelated sequences, indicating that recognition of a linear sequence segment is not a reliable indicator of sequence specificity. We asked whether any of the commonly used commercially available Aβ antibodies also recognize fibrils of unrelated sequence. Here we report that 4G8, which recognizes residues 18-23 of the Aβ sequence and is widely believed to be sequence-specific, also recognizes fibrils formed from α-synuclein and islet amyloid polypeptide (IAPP). The recognition of amyloid fibrils is aggregation-dependent because 4G8 does not recognize α-synuclein or IAPP monomer. 4G8 also stains fibrillar α-synuclein aggregates in human multiple system atrophy brain where it colocalizes with anti-α-synuclein monoclonal antibody LB509 immunoreactivity. We also found that LB509 recognizes Aβ fibrils, but not monomer, indicating that generic epitope-reactive antibodies are also produced in response to α-synuclein immunization. Taken together, our results indicate that generic fibril conformational epitope specificity may be a pervasive property among monoclonal antibodies raised against amyloid-forming antigens and that the specificity of their immunoreactivity should be rigorously established and otherwise interpreted with caution.

Background Clinical trials provide consistent evidence for buprenorphine’s efficacy in treating opioid use disorder (OUD). While the Drug Addiction Treatment Act of 2000 requires physicians to combine medication-assisted treatment (MAT) with behavioral intervention, there is no clear evidence for what form or elements of psychotherapy are most effective when coupled with MAT to treat OUD. This investigation involves focus groups designed to collect patient opinions about a specific psychotherapy, called START NOW, as well as general beliefs about various elements of psychotherapy for treating OUD. Our analysis reveals trends about patient preferences and strategies for improving OUD treatment. Methods Subjects included patients enrolled in buprenorphine/naloxone MAT at our institution’s office-based opioid treatment program. All subjects participated in a single START NOW group session, which was led by a provider (physician or nurse practitioner trained and standardized in delivering START NOW). Consented subjects participated in satisfaction surveys and audio-recorded focus groups assessing individual beliefs about various elements of psychotherapy for treating OUD. Results Overall, 38 different focus groups, 92 participation events, and 44 unique subjects participated in 1-to-6 different START NOW session/audio-recorded focus group sessions led by a certified moderator. Demographic data from 36/44 subjects was collected. Seventy-five percent (33/44) completed the START NOW Assessment Protocol, which revealed self-reported behavioral trends. Analysis of all 92 START NOW Satisfaction Questionnaire results suggests that subjects’ opinions about START NOW improved with increased participation. Our analysis of audio-recorded focus groups is divided into three subsections: content strategies for new psychotherapies, implementation strategies, and other observations. For example, participants request psychotherapies to target impulsivity and to teach future planning and build positive relationships. Conclusions The results of this study may guide implementation of psychotherapy and improve the treatment of OUD, especially as it relates to improving the modified START NOW program for treating OUD. Our study also reveals a favorable outlook of START NOW with increased participation, suggesting that any initial reticence to this program can be overcome to allow for effective implementation.