The Calpain-7 protease functions together with the ESCRT-III protein IST1 within the midbody to regulate the timing and completion of abscission.

The Endosomal Sorting Complexes Required for Transport (ESCRT) machinery mediates the membrane fission step that completes cytokinetic abscission and separates dividing cells. Filaments composed of ESCRT-III subunits constrict membranes of the intercellular bridge midbody to the abscission point. These filaments also bind and recruit cofactors whose activities help execute abscission and/or delay abscission timing in response to mitotic errors via the NoCut/Abscission checkpoint. We previously showed that the ESCRT-III subunit IST1 binds the cysteine protease Calpain-7 (CAPN7) and that CAPN7 is required for both efficient abscission and NoCut checkpoint maintenance (Wenzel et al., 2022). Here, we report biochemical and crystallographic studies showing that the tandem microtubule-interacting and trafficking (MIT) domains of CAPN7 bind simultaneously to two distinct IST1 MIT interaction motifs. Structure-guided point mutations in either CAPN7 MIT domain disrupted IST1 binding in vitro and in cells, and depletion/rescue experiments showed that the CAPN7-IST1 interaction is required for (1) CAPN7 recruitment to midbodies, (2) efficient abscission, and (3) NoCut checkpoint arrest. CAPN7 proteolytic activity is also required for abscission and checkpoint maintenance. Hence, IST1 recruits CAPN7 to midbodies, where its proteolytic activity is required to regulate and complete abscission.

Perspectives on the Use of Proprietary Blends in Dietary Supplements.

This paper discusses the rationale for use of proprietary blends on dietary supplement labels, and their implications for researchers and consumers. The Dietary Supplement Health Education Act of 1994 allows the listing of nonnutrient dietary ingredients as proprietary blends on dietary supplement labels for companies to protect their unique formulas. The weight of the blend and names of the ingredients within the blends must be declared, but not the amounts of the individual ingredients within the proprietary blend. Thus, from label information, the amount of a dietary ingredient in a proprietary blend is not available for calculating exposures in assessments of intakes or for determining doses in clinical trials.

Public Policy Experiments without Equipoise: When Is Randomization Fair?

Government agencies and nonprofit organizations have increasingly turned to randomized controlled trials (RCTs) to evaluate public policy interventions. Random assignment is widely understood to be fair when there is equipoise; however, some scholars and practitioners argue that random assignment is also permissible when an intervention is reasonably expected to be superior to other trial arms. For example, some argue that random assignment to such an intervention is fair when the intervention is scarce, for it is sometimes fair to use a lottery to allocate scarce goods. We investigate the permissibility of randomization in public policy RCTs when there is no equipoise, identifying two sets of conditions under which it is fair to allocate access to a superior intervention via random assignment. We also reject oft-made claims that alternative study designs, including stepped-wedge designs and uneven randomization, offer fair ways to allocate beneficial interventions.

Comprehensive analysis of the human ESCRT-III-MIT domain interactome reveals new cofactors for cytokinetic abscission.

The 12 related human ESCRT-III proteins form filaments that constrict membranes and mediate fission, including during cytokinetic abscission. The C-terminal tails of polymerized ESCRT-III subunits also bind proteins that contain Microtubule-Interacting and Trafficking (MIT) domains. MIT domains can interact with ESCRT-III tails in many different ways to create a complex binding code that is used to recruit essential cofactors to sites of ESCRT activity. Here, we have comprehensively and quantitatively mapped the interactions between all known ESCRT-III tails and 19 recombinant human MIT domains. We measured 228 pairwise interactions, quantified 60 positive interactions, and discovered 18 previously unreported interactions. We also report the crystal structure of the SPASTIN MIT domain in complex with the IST1 C-terminal tail. Three MIT enzymes were studied in detail and shown to: (1) localize to cytokinetic midbody membrane bridges through interactions with their specific ESCRT-III binding partners (SPASTIN-IST1, KATNA1-CHMP3, and CAPN7-IST1), (2) function in abscission (SPASTIN, KATNA1, and CAPN7), and (3) function in the 'NoCut' abscission checkpoint (SPASTIN and CAPN7). Our studies define the human MIT-ESCRT-III interactome, identify new factors and activities required for cytokinetic abscission and its regulation, and provide a platform for analyzing ESCRT-III and MIT cofactor interactions in all ESCRT-mediated processes.

Ethical Criteria for Improved Human Subject Protections in Phase I Healthy Volunteer Trials.

Phase I healthy volunteer trials test the safety and tolerability of investigational pharmaceuticals. In them, participants are exposed to study-drug risks without the possibility of direct medical benefit and typically must spend days or weeks in a residential research facility. Monetary payments are used to incentivize enrollment and compensate participants for their time. Together, these features of phase I healthy volunteer trials create a research context that differs markedly from most other clinical research, including by enrolling disproportionate numbers of economically disadvantaged people of color as participants. Due to these unique trial features and participation patterns, traditional biomedical research oversight offers inadequate ethical and policy guidance for phase I healthy volunteer research. This article details five ethical criteria crafted to be responsive to the particularities of this type of research: translational science value, fair opportunity and burden sharing, fair compensation for service, experiential welfare, and enhanced voice and recourse.

A role for Nup153 in nuclear assembly reveals differential requirements for targeting of nuclear envelope constituents.

Assembly of the nucleus following mitosis requires rapid and coordinate recruitment of diverse constituents to the inner nuclear membrane. We have identified an unexpected role for the nucleoporin Nup153 in promoting the continued addition of a subset of nuclear envelope (NE) proteins during initial expansion of nascent nuclei. Specifically, disrupting the function of Nup153 interferes with ongoing addition of B-type lamins, lamin B receptor, and SUN1 early in telophase, after the NE has initially enclosed chromatin. In contrast, effects on lamin A and SUN2 were minimal, pointing to differential requirements for the ongoing targeting of NE proteins. Further, distinct mistargeting phenotypes arose among the proteins that require Nup153 for NE targeting. Thus, disrupting the function of Nup153 in nuclear formation reveals several previously undescribed features important for establishing nuclear architecture: 1) a role for a nuclear basket constituent in ongoing recruitment of nuclear envelope components, 2) two functionally separable phases of NE formation in mammalian cells, and 3) distinct requirements of individual NE residents for continued targeting during the expansion phase of NE reformation.

Identification of abscission checkpoint bodies as structures that regulate ESCRT factors to control abscission timing.

The abscission checkpoint regulates the ESCRT membrane fission machinery and thereby delays cytokinetic abscission to protect genomic integrity in response to residual mitotic errors. The checkpoint is maintained by Aurora B kinase, which phosphorylates multiple targets, including CHMP4C, a regulatory ESCRT-III subunit necessary for this checkpoint. We now report the discovery that cytoplasmic abscission checkpoint bodies (ACBs) containing phospho-Aurora B and tri-phospho-CHMP4C develop during an active checkpoint. ACBs are derived from mitotic interchromatin granules, transient mitotic structures whose components are housed in splicing-related nuclear speckles during interphase. ACB formation requires CHMP4C, and the ESCRT factor ALIX also contributes. ACB formation is conserved across cell types and under multiple circumstances that activate the checkpoint. Finally, ACBs retain a population of ALIX, and their presence correlates with delayed abscission and delayed recruitment of ALIX to the midbody where it would normally promote abscission. Thus, a cytoplasmic mechanism helps regulate midbody machinery to delay abscission.

When a cell divides, it must first carefully duplicate its genetic information and package these copies into compartments housed in the two new cells. Errors in this process lead to genetic mistakes that trigger cancer or other harmful biological events. Quality control checks exist to catch errors before it is too late. This includes a final 'abscission' checkpoint right before the end of division, when the two new cells are still connected by a thin membrane bridge. If cells fail to pass this 'no cut' checkpoint, they delay severing their connection until the mistake is fixed. A group of proteins called ESCRTs is responsible for splitting the two cells apart if nothing is amiss. The abscission checkpoint blocks this process by altering certain proteins in the ESCRT complex, but exactly how this works is not yet clear. To find out more, Williams et al. imaged ESCRT factors in a new experimental system in which the abscission checkpoint is active in many cells. This showed that, in this context, certain ESCRT components were rerouted from the thread of membrane between the daughter cells to previously unknown structures, which Williams et al. named abscission checkpoint bodies. These entities also sequestered other factors that participate in the abscission checkpoint and factors that contribute to gene expression. These results are key to better understand how cells regulate their division; in particular, they provide a new framework to explore when this process goes wrong and contributes to cancer.

Labeling of Cannabidiol Products: A Public Health Perspective.

Introduction: Interest in the therapeutic use of cannabidiol (CBD) has reached a fever-pitch in recent months, as CBD-containing products appear everywhere from online retailers to grocery stores and gas stations. The widespread availability of hemp-derived CBD products is confounding given that CBD is a U.S. Food and Drug Administration (FDA)-approved drug, and thus precluded from being added to food and beverages, or included in dietary supplements. The use by manufacturers of disease-related claims on marketing materials and product labels, along with the federal legalization of hemp in December 2018, has created political pressure on FDA to promulgate regulations. Conclusions: Accurate and informative labeling of hemp and hemp-derived CBD products is an important public health issue. FDA-regulated product labels are considered an essential tool for protecting consumers and enabling informed decision-making. Untruthful or unsubstantiated health-related claims, and unallowed Drug Claims, in marketing materials and on labels of CBD products may create harm by enticing consumers to forgo more evidence-based medical interventions. Furthermore, missing or inaccurate labeling of the amount of CBD, delta-9 tetrahydrocannabinol (THC), and potentially harmful contaminants such as pesticides, naturally-occurring yeast and mold or heavy metals may result in harm and/or lack of efficacy. Manufacturers of these products may reasonably be expected to understand and adhere to FDA regulations for labeling and marketing of food, dietary supplements and drugs, both over-the-counter (OTC) and prescription, even though FDA has interpreted federal law as excluding them from these categories. As manufacturers prepare for forthcoming regulations, a better understanding of the basic framework for FDA labeling and marketing regulations for food, dietary supplements and drugs is warranted.

Reconsidering scarce drug rationing: implications for clinical research.

Hospital systems commonly face the challenge of determining just ways to allocate scarce drugs during national shortages. There is no standardised approach of how this should be instituted, but principles of distributive justice are commonly used so that patients who are most likely to benefit from the drug receive it. As a result, clinical indications, in which the evidence for the drug is assumed to be established, are often prioritised over research use. In this manuscript, we present a case of a phase II investigational trial of intravenous thiamine for delirium prevention in patients undergoing haematopoietic stem cell transplantation to emphasise several shortcomings in the overarching prioritisation of clinical over research uses of scarce drugs. Specifically, we present the following considerations: (1) clinical use may not have stronger evidence than research use; (2) a strong scientific rationale for research use may outweigh the claim for clinical indications in which there is weak evidence; (3) treatment within the context of a clinical trial may be the standard of care; and (4) research use may not only benefit patients receiving the treatment but also offers the prospect of improving future clinical care. In summary, we argue against allocation schemes that prohibit all research uses of scarce drugs and instead recommend that allocation schemes include a balanced approach that weighs risks and benefits of access to scarce drugs irrespective of the research versus clinical use designation.

Systematic Discovery of Short Linear Motifs Decodes Calcineurin Phosphatase Signaling.

Short linear motifs (SLiMs) drive dynamic protein-protein interactions essential for signaling, but sequence degeneracy and low binding affinities make them difficult to identify. We harnessed unbiased systematic approaches for SLiM discovery to elucidate the regulatory network of calcineurin (CN)/PP2B, the Ca2+-activated phosphatase that recognizes LxVP and PxIxIT motifs. In vitro proteome-wide detection of CN-binding peptides, in vivo SLiM-dependent proximity labeling, and in silico modeling of motif determinants uncovered unanticipated CN interactors, including NOTCH1, which we establish as a CN substrate. Unexpectedly, CN shows SLiM-dependent proximity to centrosomal and nuclear pore complex (NPC) proteins-structures where Ca2+ signaling is largely uncharacterized. CN dephosphorylates human and yeast NPC proteins and promotes accumulation of a nuclear transport reporter, suggesting conserved NPC regulation by CN. The CN network assembled here provides a resource to investigate Ca2+ and CN signaling and demonstrates synergy between experimental and computational methods, establishing a blueprint for examining SLiM-based networks.

Cannabidiol and Other Cannabinoids: From Toxicology and Pharmacology to the Development of a Regulatory Pathway.

Cannabidiol (CBD) is a non-psychotropic constituent of Cannabis sativa that has grown in popularity during the last decade. CBD is the active component of EPIDIOLEX®, a U.S. Food and Drug Administration (FDA)-approved drug designed for the treatment of drug-resistant pediatric epileptic seizures associated with several rare syndromes. Furthermore, CBD has been proposed as a treatment for a number of other diseases for which clinical trials are now ongoing. Accumulating evidence indicates that the number of "CBD-containing" products, available mostly online, is growing exponentially. However, the U.S. FDA currently prohibits sales of CBD as a dietary supplement (DS) or ingredient in conventional food. Further, clear federal regulatory and quality oversight does not exist, which has led to an uncontrolled CBD market that, in turn, threatens to result in negative health effects experienced by a trusting public. Thus, there are open questions demanding answers in the very near future: For which medical purposes is CBD provably effective? Can it be used safely as a non-prescription product? At what level? Is a hemp extract that contains CBD a different ingredient than isolated CBD? Is CBD safe for everyone? What is a future path for hemp products with CBD as well as for other cannabinoids? Should CBD be allowed as a drug only, or is there a way for hemp extracts to be listed as a dietary supplement and food ingredient? This Special Issue, the first of its kind on CBD and other phytocannabinoids, is devoted to answering those and other questions by publishing articles in the fields of pharmacology, toxicology, and regulation.

Biochar amendment as a remediation strategy for surface soils impacted by crude oil.

The impact of organic bulking agents on the biodegradation of petroleum hydrocarbons in crude oil impacted soils was evaluated in batch laboratory experiments. Crude oil impacted soils from three separate locations were amended with fertilizer and bulking agents consisting of biochars derived from walnut shells or ponderosa pine wood chips produced at 900 °C. The batch reactors were incubated at 25 °C and sampled at pre-determined intervals to measure changes in total petroleum hydrocarbons (TPH) over time. For the duration of the incubation, the soil moisture content was adjusted to 75% of the maximum water holding capacity (MWHC) and prior to each sampling event, the sample was manually stirred. Results show that the addition of fertilizer and bulking agents increased biodegradation rates of TPH. Soil samples amended with ponderosa pine wood biochar achieved the highest biodegradation rate, whereas the walnut shell biochar was inhibitory to TPH biodegradation. The beneficial impact of biochars on TPH biodegredation was more pronounced for a soil impacted with lighter hydrocarbons compared to a soil impacted with heavier hydrocarbons. This study demonstrates that some biochars, in combination with fertilizer, have the potential to be a low-technology and eco-friendly remediation strategy for crude oil impacted soils.

Selecting participants fairly for controlled human infection studies.

Controlled human infection (CHI) studies involve the deliberate exposure of healthy research participants to infectious agents to study early disease processes and evaluate interventions under controlled conditions with high efficiency. Although CHI studies expose participants to the risk of infection, they are designed to offer investigators unique advantages for studying the pathogenesis of infectious diseases and testing potential vaccines or treatments in humans. One of the central challenges facing investigators involves the fair selection of research subjects to participate in CHI studies. While there is widespread agreement that investigators have a duty to select research participants fairly, this principle also yields conflicting ethical imperatives, for example requiring investigators to both exclude potential participants with co-morbidities since they face increased risks, but also to include them in order to ensure generalizability. In this paper we defend an account of fair subject selection that is tailored to the context of CHI studies. We identify the considerations of fairness that bear directly on selecting participants for CHI studies and provide investigators and members of IRBs and RECs with a principled way to navigate the conflicting imperatives to which these considerations give rise.

Four Faces of Fair Subject Selection.

Although the principle of fair subject selection is a widely recognized requirement of ethical clinical research, it often yields conflicting imperatives, thus raising major ethical dilemmas regarding participant selection. In this paper, we diagnose the source of this problem, arguing that the principle of fair subject selection is best understood as a bundle of four distinct sub-principles, each with normative force and each yielding distinct imperatives: (1) fair inclusion; (2) fair burden sharing; (3) fair opportunity; and (4) fair distribution of third-party risks. We first map out these distinct sub-principles, and then identify the ways in which they yield conflicting imperatives for the design of inclusion and exclusion criteria, and the recruitment of participants. We then offer guidance for how decision makers should navigate these conflicting imperatives to ensure that participants are selected fairly.

Serious Adverse Events Reported with Dietary Supplement Use in the United States: A 2.5 Year Experience.

Dietary supplement marketers assure the safety of their products by complying with current good manufacturing practices and a host of federal regulations, including those enforced by the Food and Drug Administration (FDA). Post-market surveillance is a key part of identifying safety problems associated with dietary supplement products. FDA requires dietary supplement marketers to provide a domestic address or phone number on product labels for consumers, family members, or health care professionals to report adverse events (AEs) associated with product use and to report all serious adverse events (SAEs) to the agency within 15 business days of receipt. We aimed to evaluate the characteristics of AEs reported with dietary supplement use, including dietary supplement type and Medical Dictionary for Regulatory Activities (MedDRA) system organ class (SOC) that occur with reported SAEs. A total of 41,121 unique adverse event cases reported to two large, U.S.-based dietary supplement marketers in a 2.5-year period (March 1, 2014-August 31, 2016) were assessed for seriousness using established criteria. Each SAE was assigned one or more MedDRA preferred terms and system organ classes (SOC). The types of supplements most responsible for SAEs were assessed. Of the 41,121 AE cases reported, 203 (0.48%) were SAEs. SAEs tended to occur with products marketed for weight loss (69.0%) and glycemic control (19.2%). SAEs occurred most commonly in the cardiovascular, gastrointestinal, and nervous system disorder SOCs. The percentage of SAEs reported to dietary supplement marketers is low, predominantly among consumers of two types of supplements. Further study is needed among a larger cohort of supplement users to determine causal associations between types of supplement products and serious adverse events.

Geographic Location and Moral Arbitrariness in the Allocation of Donated Livers.

The federal system for allocating donated livers in the United States is often criticized for allowing geographic disparities in access to livers. Critics argue that such disparities are unfair on the grounds that where one lives is morally arbitrary and so should not influence one's access to donated livers. They argue instead that livers should be allocated in accordance with the equal opportunity principle, according to which US residents who are equally sick should have the same opportunity to receive a liver, regardless of where they live. In this paper, we examine a central premise of the argument for the equal opportunity principle, namely, that geographic location is a morally arbitrary basis for allocating livers. We raise some serious doubts regarding the truth of this premise, arguing that under certain conditions, factors closely associated with geographic location are relevant to the allocation of livers, and so that candidates' geographic location is sometimes a morally non-arbitrary basis for allocating livers. Geographic location is morally non-arbitrary, we suggest, since by taking it into account, the UNOS may better fulfill its central goals of facilitating the effective and efficient placement of organs for transplantation and increasing organ donation.

Douglas MacKay, ND: Defining the Regulatory Landscape for Hemp-based Supplements.

No Abstract Available.