Engineered Chimeras Unveil Swappable Modular Features of Fatty Acid and Polyketide Synthase Acyl Carrier Proteins.

The strategic redesign of microbial biosynthetic pathways is a compelling route to access molecules of diverse structure and function in a potentially environmentally sustainable fashion. The promise of this approach hinges on an improved understanding of acyl carrier proteins (ACPs), which serve as central hubs in biosynthetic pathways. These small, flexible proteins mediate the transport of molecular building blocks and intermediates to enzymatic partners that extend and tailor the growing natural products. Past combinatorial biosynthesis efforts have failed due to incompatible ACP-enzyme pairings. Herein, we report the design of chimeric ACPs with features of the actinorhodin polyketide synthase ACP (ACT) and of the Escherichia coli fatty acid synthase (FAS) ACP (AcpP). We evaluate the ability of the chimeric ACPs to interact with the E. coli FAS ketosynthase FabF, which represents an interaction essential to building the carbon backbone of the synthase molecular output. Given that AcpP interacts with FabF but ACT does not, we sought to exchange modular features of ACT with AcpP to confer functionality with FabF. The interactions of chimeric ACPs with FabF were interrogated using sedimentation velocity experiments, surface plasmon resonance analyses, mechanism-based cross-linking assays, and molecular dynamics simulations. Results suggest that the residues guiding AcpP-FabF compatibility and ACT-FabF incompatibility may reside in the loop I, α-helix II region. These findings can inform the development of strategic secondary element swaps that expand the enzyme compatibility of ACPs across systems and therefore represent a critical step toward the strategic engineering of "un-natural" natural products.

An Assessment of Which Sociodemographic and Spinal Cord Injury-Specific Characteristics Influence Engagement With Experimental Therapies and Participation in Clinical Trials.

Background: Although a number of experimental therapies for spinal cord injury (SCI) have recently emerged, few authors have examined the goals of individuals with SCI considering experimental therapies, and none have determined whether sociodemographic and injury-specific characteristics influence that engagement. Objectives: To determine (a) the goals of individuals with SCI who are considering experimental therapies; (b) whether sociodemographic factors, injury-specific characteristics, and concerns over adverse events influence those goals and/or participation in experimental therapies and clinical trials; and (c) whether people with SCI feel they have adequate information about experimental therapies and clinical trials. Methods: An online survey that yielded 364 responses. Results: Most respondents (83.7%) had sought information about experimental therapies, and just under half (47.8%) had received one. The most frequently cited functional goals were improvement in bowel and bladder function and elimination of dysreflexia (60.4%). Several goals were influenced by age and level and completeness of injury, and most respondents (93.4%) wanted more information about experimental therapies. Just over one-third (34.6%) of respondents had participated in a clinical trial, and nearly all (96.9%) wanted more information about them. Having received experimental therapies and participated in clinical trials was positively correlated with seeking SCI-specific care from an SCI specialist rather than from a primary care physician. Most (83.9%) respondents would avoid or be reluctant to engage with a medical center if they were made aware of harm done to trial participants. Conclusion: This work suggests that there are unmet information needs among people with SCI, specifically pertaining to experimental therapies and clinical trials. It also reveals that improved access to SCI specialists may enhance access to novel treatments and research efforts. Being made aware of harm to trial participants may influence the decision of individuals with SCI to seek care at or enroll in trials at these clinical sites.

How individuals with spinal cord injury in the United States access and assess information about experimental therapies and clinical trials: results of a clinical survey.

STUDY DESIGN: An internet-based survey. OBJECTIVES: To determine how individuals with spinal cord injury (SCI) access information about experimental therapies and clinical trials. To understand which factors influence receipt of and perceived trustworthiness of that information. SETTING: Two academic medical centers and an SCI organization. METHODS: Demographic information frequencies and percentages were calculated then analyzed using chi-square tests for independence. Fisher's exact test of independence was used to assess significance for contingency tables with categories containing expected counts below five. RESULTS: Three hundred sixty four persons with SCI participated in the survey. Most felt confident in their ability to evaluate SCI-specific information from a variety of sources, though SCI organizations and the medical literature were deemed the most reliable. Information from SCI specialists was deemed more credible than that from non-SCI specialists, but only 53.6% of participants had access to them. Nearly all (89.0%) respondents who had sought information about experimental therapies had found it online, while 51.4% of those who had participated in a clinical trial had been contacted by a research team. Only 8.4% of participants felt their medical teams offered them sufficient information about experimental therapies and clinical trials. Wealthier and more educated respondents were more knowledgeable about health-related resources on the internet. Nearly all participants (96.9%) expressed interest in learning more about trials related to SCI. CONCLUSIONS: There is an information deficit among people with SCI pertaining to experimental therapies and clinical trials. It is exacerbated by lack of income, education, and access to SCI specialists.

A case of postprandial hypotension in an individual with cervical spinal cord injury: treatment with acarbose.

Introduction: Postprandial hypotension (PPH) is a postmeal drop in systolic blood pressure that may or may not be symptomatic. While the etiologies of PPH are incompletely understood, it is thought to occur when glucose absorption causes increased splanchnic blood flow or "pooling" in people who lack sufficient compensatory responses to support their systemic blood pressure. Postprandial hypotension is well described in individuals with neurodegenerative diseases, yet only rarely in people living with spinal cord injury (SCI). Acarbose is an alpha-glucosidase inhibitor that treats PPH by slowing gastric transit time and reducing glucose uptake in the small intestine, hence decreasing superior mesenteric artery blood flow. Case presentation: A 62-year-old woman with long-standing cervical SCI presented with 5 years of worsening postprandial lightheadedness, visual "flashes", and neck pain. She had had multiple episodes of near and frank syncope and her prior medical team had initiated midodrine three times daily. We began treatment with acarbose, starting at 50 mg with each meal and rapidly titrating to 100 mg at mealtime. She noticed an immediate improvement in her symptoms and an attenuation of postmeal drops in both systolic and diastolic blood pressures. Discussion: To our knowledge, this is one of the first described cases of PPH among people living with SCI. Given the autonomic dysfunction that frequently accompanies higher-level of injuries, it is possible that many more people with SCI have this condition, whether or not it is symptomatic. Acarbose is one of the several established treatments for PPH, and proved effective and tolerable for our patient.

Altered Gene-Regulatory Function of KDM5C by a Novel Mutation Associated With Autism and Intellectual Disability.

Intellectual disability (ID) affects up to 2% of the population world-wide and often coincides with other neurological conditions such as autism spectrum disorders. Mutations in KDM5C cause Mental Retardation, X-linked, Syndromic, Claes-Jensen type (MRXSCJ, OMIM #300534) and are one of the most common causes of X-linked ID. KDM5C encodes a histone demethylase for di- and tri-methylated histone H3 lysine 4 (H3K4me2/3), which are enriched in transcriptionally engaged promoter regions. KDM5C regulates gene transcription; however, it remains unknown whether removal of H3K4me is fully responsible for KDM5C-mediated gene regulation. Most mutations functionally tested to date result in reduced enzymatic activity of KDM5C, indicating loss of demethylase function as the primary mechanism underlying MRXSCJ. Here, we report a novel KDM5C mutation, R1115H, identified in an individual displaying MRXSCJ-like symptoms. The carrier mother's cells exhibited a highly skewed X-inactivation pattern. The KDM5C-R1115H substitution does not have an impact on enzymatic activity nor protein stability. However, when overexpressed in post-mitotic neurons, KDM5C-R1115H failed to fully suppress expression of target genes, while the mutant also affected expression of a distinct set of genes compared to KDM5C-wildtype. These results suggest that KDM5C may have non-enzymatic roles in gene regulation, and alteration of these roles contributes to MRXSCJ in this patient.