Mitochondrial protein transport: Versatility of translocases and mechanisms.

Biogenesis of mitochondria requires the import of approximately 1,000 different precursor proteins into and across the mitochondrial membranes. Mitochondria exhibit a wide variety of mechanisms and machineries for the translocation and sorting of precursor proteins. Five major import pathways that transport proteins to their functional intramitochondrial destination have been elucidated; these pathways range from the classical amino-terminal presequence-directed pathway to pathways using internal or even carboxy-terminal targeting signals in the precursors. Recent studies have provided important insights into the structural organization of membrane-embedded preprotein translocases of mitochondria. A comparison of the different translocases reveals the existence of at least three fundamentally different mechanisms: two-pore-translocase, ß-barrel switching, and transport cavities open to the lipid bilayer. In addition, translocases are physically engaged in dynamic interactions with respiratory chain complexes, metabolite transporters, quality control factors, and machineries controlling membrane morphology. Thus, mitochondrial preprotein translocases are integrated into multi-functional networks of mitochondrial and cellular machineries.

Central role of Tim17 in mitochondrial presequence protein translocation.

The presequence translocase of the mitochondrial inner membrane (TIM23) represents the major route for the import of nuclear-encoded proteins into mitochondria1,2. About 60% of more than 1,000 different mitochondrial proteins are synthesized with amino-terminal targeting signals, termed presequences, which form positively charged amphiphilic α-helices3,4. TIM23 sorts the presequence proteins into the inner membrane or matrix. Various views, including regulatory and coupling functions, have been reported on the essential TIM23 subunit Tim17 (refs. 5-7). Here we mapped the interaction of Tim17 with matrix-targeted and inner membrane-sorted preproteins during translocation in the native membrane environment. We show that Tim17 contains conserved negative charges close to the intermembrane space side of the bilayer, which are essential to initiate presequence protein translocation along a distinct transmembrane cavity of Tim17 for both classes of preproteins. The amphiphilic character of mitochondrial presequences directly matches this Tim17-dependent translocation mechanism. This mechanism permits direct lateral release of transmembrane segments of inner membrane-sorted precursors into the inner membrane.

The histone deacetylase Sirt6 regulates glucose homeostasis via Hif1alpha.

SIRT6 is a member of a highly conserved family of NAD(+)-dependent deacetylases with various roles in metabolism, stress resistance, and life span. SIRT6-deficient mice develop normally but succumb to a lethal hypoglycemia early in life; however, the mechanism underlying this hypoglycemia remained unclear. Here, we demonstrate that SIRT6 functions as a histone H3K9 deacetylase to control the expression of multiple glycolytic genes. Specifically, SIRT6 appears to function as a corepressor of the transcription factor Hif1alpha, a critical regulator of nutrient stress responses. Consistent with this notion, SIRT6-deficient cells exhibit increased Hif1alpha activity and show increased glucose uptake with upregulation of glycolysis and diminished mitochondrial respiration. Our studies uncover a role for the chromatin factor SIRT6 as a master regulator of glucose homeostasis and may provide the basis for novel therapeutic approaches against metabolic diseases, such as diabetes and obesity.

Patient-reported outcomes in ZUMA-7, a phase 3 study of axicabtagene ciloleucel in second-line large B-cell lymphoma.

Here, we report the first comparative analysis of patient-reported outcomes (PROs) with chimeric antigen receptor T-cell therapy vs standard-of-care (SOC) therapy in second-line relapsed/refractory large B-cell lymphoma (R/R LBCL) from the pivotal randomized phase 3 ZUMA-7 study of axicabtagene ciloleucel (axi-cel) vs SOC. PRO instruments were administered at baseline, day 50, day 100, day 150, month 9, and every 3 months from randomization until 24 months or an event-free survival event. The quality of life (QoL) analysis set comprised patients with a baseline and ≥1 follow-up PRO completion. Prespecified hypotheses for Quality of Life Questionnaire-Core 30 (QLQ-C30) physical functioning, global health status/QoL, and EQ-5D-5L visual analog scale (VAS) were tested using mixed-effects models with repeated measures. Clinically meaningful changes were defined as 10 points for QLQ-C30 and 7 for EQ-5D-5L VAS. Among 359 patients, 296 (165 axi-cel, 131 SOC) met inclusion criteria for QoL analysis. At day 100, statistically significant and clinically meaningful differences in mean change of scores from baseline were observed favoring axi-cel over SOC for QLQ-C30 global health status/QoL (estimated difference 18.1 [95% confidence interval (CI), 12.3-23.9]), physical functioning (13.1 [95% CI, 8.0-18.2]), and EQ-5D-5L VAS (13.7 [95% CI, 8.5-18.8]; P < .0001 for all). At day 150, scores significantly favored axi-cel vs SOC for global health status/QoL (9.8 [95% CI, 2.6-17.0]; P = .0124) and EQ-5D-5L VAS (11.3 [95% CI, 5.4-17.1]; P = .0004). Axi-cel showed clinically meaningful improvements in QoL over SOC. Superior clinical outcomes and favorable patient experience with axi-cel should help inform treatment choices in second-line R/R LBCL. This trial was registered at www.clinicaltrials.gov as #NCT03391466.

Continuous and differential improvement in worldwide access to hematopoietic cell transplantation: activity has doubled in a decade with a notable increase in unrelated and non-identical related donors.

Promoting access to and excellence in hematopoietic cell transplantation (HCT) by collecting and disseminating data on global HCT activities is one of the principal activities of the Worldwide Network for Blood and Marrow Transplantation, a non-Governmental organization in working relations with the World Health Organization. HCT activities are recorded annually by member societies, national registries and individual centers including indication, donor type (allogeneic/autologous), donor match and stem cell source (bone marrow/peripheral blood stem cells/cord blood). In 2018, 1,768 HCT teams in 89 countries (six WHO regions) reported 93,105 (48,680 autologous and 44,425 allogeneic) HCT. Major indications were plasma cell disorders and lymphoma for autologous, and acute leukemias and MDS/MPN for allogeneic HCT. HCT number increased from 48,709 in 2007. Notable increases were seen for autoimmune diseases in autologous and hemoglobinopathies in allogeneic HCT. The number of allogeneic HCT more than doubled with significant changes in donor match. While HCT from HLA identical siblings has seen only limited growth, HCT from non-identical related donors showed significant increase worldwide. Strongest correlation between economic growth indicator of gross national income/capita and HCT activity/ten million population was observed for autologous HCT (r=0.79). HCT from unrelated donors showed strong correlation (r=0.68), but only moderate correlation (r=0.51) was detected from related donors. The use of HCT doubled in about a decade worldwide at different speed and with significant changes regarding donor match as a sign of improved access to HCT worldwide. Although narrowing, significant gaps remain between developing and non-developing countries.

Using narratives to correct politically charged health misinformation and address affective belief echoes.

BACKGROUND: In May 2020, news outlets reported misinformation about the Centers for Disease Control (CDC) related to COVID-19. Correcting misinformation about outbreaks and politics is particularly challenging. Affective belief echoes continue to influence audiences even after successful correction. Narrative and emotional flow scholarship suggest that a narrative corrective with a positive ending could reduce belief echoes. Therefore, this study investigated the efficacy of a narrative corrective with a relief ending for correcting misinformation about the CDC. METHODS: Between 29 May and 4 June 2020, we tested the effectiveness of a narrative to correct this misinformation. Participants in the United States (N = 469) were enrolled via Qualtrics panels in an online message experiment and randomized to receive a narrative corrective, a didactic corrective or no corrective. RESULTS: The narrative corrective resulted in lower endorsement of the misinformation compared with the control and the didactic corrective. The narrative corrective had a positive indirect effect on perceived CDC competence and mask wearing intentions for politically moderate and conservative participants via relief. CONCLUSIONS: Public health institutions, such as the CDC, should consider utilizing narrative messaging with positive emotion endings to correct misinformation. Narratives better address affective belief echoes, particularly for counter-attitudinal audiences.

Framing COVID-19 Preprint Research as Uncertain: A Mixed-Method Study of Public Reactions.

During the COVID-19 pandemic, journalists were encouraged to convey uncertainty surrounding preliminary scientific evidence, including mentioning when research is unpublished or unverified by peer review. To understand how public audiences interpret this information, we conducted a mixed method study with U.S. adults. Participants read a news article about preprint COVID-19 vaccine research in early April 2021, just as the vaccine was becoming widely available to the U.S. public. We modified the article to test two ways of conveying uncertainty (hedging of scientific claims and mention of preprint status) in a 2 × 2 between-participants factorial design. To complement this, we collected open-ended data to assess participants' understanding of the concept of a scientific preprint. In all, participants who read hedged (vs. unhedged) versions of the article reported less favorable vaccine attitudes and intentions and found the scientists and news reporting less trustworthy. These effects were moderated by participants' epistemic beliefs and their preference for information about scientific uncertainty. However, there was no impact of describing the study as a preprint, and participants' qualitative responses indicated a limited understanding of the concept. We discuss implications of these findings for communicating initial scientific evidence to the public and we outline important next steps for research and theory-building.

Political Party Collective Norms, Perceived Norms, and Mask Wearing Behavior: A Test of the Theory of Normative Social Behavior.

The theory of normative social behavior (TNSB) postulates that people are influenced by others' behaviors, which they observe from messages and experience. In addition to focusing on perceived (i.e., descriptive and injunctive) norms, the TNSB was expanded to include collective norms, which represent what people actually do. Testing this expanded theoretical model, the current study examined whether two types of collective norms - collective political norms and collective regional norms - interacted with descriptive norms to influence pandemic mask wearing behavior expectations among U.S. adults (N = 444). The interaction was statistically significant for collective political norms (ß = -.74, p = .009) but not collective regional norms (ß = -.16, p = .85). Specifically, descriptive norms were related to increased mask wearing expectation for all values of political party collective norms, but the effects were stronger when political party collective norms were low (i.e., low mask wearing behavior was normative). The findings support the inclusion of collective norms in the TNSB, clarify the relationships among different types of norms, and provide insights for norms-based interventions.

Squaramides for colorimetric and fluorescent anion sensing.

A series of fluorophore-containing squaramides were synthesised to investigate the fluorescent and colorimetric response to anions of squaramides containing large aromatic substituents. Squaramides in which the fluorophores were conjugated directed to the squaramide motif were found to have highly acidic NH protons, giving rise to complicated fluorescence behaviour and colour changes upon addition of anions. In contrast, squaramides incorporating a methylene spacer to electronically insulate the fluorophore from the squaramide gave a relatively simple fluorescence response upon addition of anions, which was attributed to a decrease in excimer emission relative to monomer emission intensity, likely due to a disaggregation mechanism. The ratio of excimer : monomer emission was used to provide a ratiometric fluorescent response to anions, with the most selective molecules demonstrating a preference for binding to sulfate over other anions.

Water-Soluble Squaramide-Functionalized Copolymers for Anion Recognition.

A series of ethylene glycol-based squaramide-containing copolymers are synthesized via a post-polymerization functionalization strategy. Conversion of polymeric amines to squaramides is found to proceed in good yields, representing a versatile method of incorporating squaramides into polymers for anion recognition. Analysis of the polymers by UV-Vis and fluorescence spectroscopy revealed that anion binding takes place similarly to that of small-molecule squaramides. The presence of a fluorescent sensing group on polymer-bound squaramides allowed for a fluorescent sensing mechanism for anions that followed a similar trend in selectivity in aqueous DMSO solution, with selectivity observed for H2 PO4 - , AcO- and SO4 2- over other common anions tested. The anion response and selectivity towards anions is similar to that of analogous small-molecule squaramides, however polymeric squaramides exhibited a greater resistance to deprotonation by more basic anions, which is attributed to the closer proximity of individual squaramides on a macromolecule. The squaramide-containing polymers exhibited good water solubility, overcoming a common problem for anion sensors which are typically not sufficiently soluble in water to function in many required applications. Despite no anion binding being observed in water, this study represents a simple and effective method of creating fully water-soluble anion receptors which may be adapted to give improved binding affinity and selectivity depending on the anion binding moiety.

Secondary ionization of pyrimidine nucleobases and their microhydrated derivatives in helium nanodroplets.

Radiation damage in biological systems by ionizing radiation is predominantly caused by secondary processes such as charge and energy transfer leading to the breaking of bonds in DNA. Here, we study the fragmentation of cytosine (Cyt) and thymine (Thy) molecules, clusters and microhydrated derivatives induced by direct and indirect ionization initiated by extreme-ultraviolet (XUV) irradiation. Photofragmentation mass spectra and photoelectron spectra of free Cyt and Thy molecules are compared with mass and electron spectra of Cyt/Thy clusters and microhydrated Cyt/Thy molecules formed by aggregation in superfluid helium (He) nanodroplets. Penning ionization after resonant excitation of the He droplets is generally found to cause less fragmentation compared to direct photoionization and charge-transfer ionization after photoionization of the He droplets. When Cyt/Thy molecules and oligomers are complexed with water molecules, their fragmentation is efficiently suppressed. However, a similar suppression of fragmentation is observed when homogeneous Cyt/Thy clusters are formed in He nanodroplets, indicating a general trend. Penning ionization electron spectra (PIES) of Cyt/Thy are broad and nearly featureless but PIES of their microhydrated derivatives point at a sequential ionization process ending in unfragmented microsolvated Cyt/Thy cations.

Hailey-Hailey Disease is Associated with Diabetes: A Population-based Cohort Study, Clinical Cohort Study, and Pedigree Analysis.

Hailey-Hailey disease is a rare hereditary skin disease caused by mutations in the ATP2C1 gene encoding the secretory pathway Ca2+/Mn2+-ATPase 1 (SPCA1) protein. Extracutaneous manifestations of Hailey-Hailey disease are plausible but still largely unknown. The aim of this study was to explore the association between Hailey-Hailey disease and diabetes. A population-based cohort study of 347 individuals with Hailey-Hailey  disease was performed to assess the risks of type 1  diabetes and type 2 diabetes, using Swedish nationwide registries. Pedigrees from 2 Swedish families with Hailey-Hailey disease were also investigated: 1 with concurrent type 1 diabetes and HLA-DQ3, the other with type 2 diabetes. Lastly, a clinical cohort with 23 individuals with Hailey-Hailey disease and matched healthy controls was evaluated regarding diabetes. In the register data males with Hailey-Hailey disease had a 70% elevated risk of type 2 diabetes, whereas no  excess risk among women could be confirmed. In both pedigrees an unusually high inheritance for diabetes was observed. In the clinical cohort, individuals with Hailey-Hailey disease displayed a metabolic phenotype indicative of type 2 diabetes. Hailey-Hailey disease seems to act as a synergistic risk factor for diabetes. This study indicates, for the first time, an association between Hailey-Hailey disease and diabetes and represents human evidence that SPCA1 and the Golgi apparatus may be implicated in diabetes pathophysiology.

Dopant ionization and efficiency of ion and electron ejection from helium nanodroplets.

Photoionization spectroscopy and mass spectrometry of doped helium (He) nanodroplets rely on the ability to efficiently detect ions and/or electrons. Using a commercial quadrupole mass spectrometer and a photoelectron-photoion coincidence spectrometer, we systematically measure yields of ions and electrons created in pure and doped He nanodroplets in a wide size range and in two ionization regimes-direct ionization and secondary ionization after resonant photoexcitation of the droplets. For two different types of dopants (oxygen molecules, O2, and lithium atoms, Li), we infer the optimal droplet size to maximize the yield of ejected ions. When dopants are ionized by charge-transfer to photoionized He nanodroplets, the highest yield of O2 and Li ions is detected for a mean size of ∼5×104 He atoms per nanodroplet. When dopants are Penning ionized via photoexcitation of the He droplets, the highest yield of O2 and Li ions is detected for ∼103 and ∼105 He atoms per droplet, respectively. At optimum droplet sizes, the detection efficiency of dopant ions in proportion to the number of primary photoabsorption events is up to 20% for charge-transfer ionization of O2 and 2% for Li, whereas for Penning ionization it is 1% for O2 and 4% for Li. Our results are instrumental in determining optimal conditions for mass spectrometric studies and photoionization spectroscopy of molecules and complexes isolated in He nanodroplets.

Human GTPBP5 is involved in the late stage of mitoribosome large subunit assembly.

Human mitoribosomes are macromolecular complexes essential for translation of 11 mitochondrial mRNAs. The large and the small mitoribosomal subunits undergo a multistep maturation process that requires the involvement of several factors. Among these factors, GTP-binding proteins (GTPBPs) play an important role as GTP hydrolysis can provide energy throughout the assembly stages. In bacteria, many GTPBPs are needed for the maturation of ribosome subunits and, of particular interest for this study, ObgE has been shown to assist in the 50S subunit assembly. Here, we characterize the role of a related human Obg-family member, GTPBP5. We show that GTPBP5 interacts specifically with the large mitoribosomal subunit (mt-LSU) proteins and several late-stage mitoribosome assembly factors, including MTERF4:NSUN4 complex, MRM2 methyltransferase, MALSU1 and MTG1. Interestingly, we find that interaction of GTPBP5 with the mt-LSU is compromised in the presence of a non-hydrolysable analogue of GTP, implying a different mechanism of action of this protein in contrast to that of other Obg-family GTPBPs. GTPBP5 ablation leads to severe impairment in the oxidative phosphorylation system, concurrent with a decrease in mitochondrial translation and reduced monosome formation. Overall, our data indicate an important role of GTPBP5 in mitochondrial function and suggest its involvement in the late-stage of mt-LSU maturation.

Developing skin cancer education materials for darker skin populations: crowdsourced design, message targeting, and acral lentiginous melanoma.

Despite decreased susceptibility, darker skin individuals who develop melanoma have worse survival. This disparity in melanoma mortality is the largest for any cancer, and partly driven by a lack of patient education materials targeted to darker skin populations in whom acral lentiginous melanoma (ALM) is the most common subtype. To address this communication disparity, the current study reports a multi-phase design process that leverages crowdsourcing and message testing to develop ALM-focused patient education materials for darker skin populations. Crowdsourced design was utilized to develop a pool of designs (phase 1), the pool was narrowed and thematically analyzed (phase 2), and select designs were evaluated via a message experiment (N = 1877). For darker skin populations, designs that depicted people enhanced knowledge of ALM through message memorability. The current study engages melanoma disparities by providing ALM patient education materials for darker skin populations vetted via a multi-phase process.

People Wear Masks when they Ski: Comparing Congruent and Incongruent Behavioral Context Appeals.

When advocating for a behavior, persuasive messaging typically focuses on the context that behavior is performed in, such as mask-wearing during the COVID-19 pandemic. However, situating the advocated behavior in a different context, termed an incongruent context appeal, may persuade by increasing attention, novelty, and memorability. The current study tested this supposition in a message experiment. Participants (N = 324) were randomized to view an incongruent context (e.g. skiing) or a congruent context (i.e. COVID-19) appeal advocating for mask wearing. The incongruence appeal had a direct, positive effect on mask wearing intentions and indirect, positive effects via two serial mediation pathways: time spent with the message increased attention through novelty and memorability. Findings suggest that an incongruent context appeal is an effective strategy for persuading audiences in information-saturated environments like the COVID-19 pandemic.

Spit, Disgust, and Parasite Stress Theory: A Message Experiment.

Public health interventions targeting coughing and spitting during the Tuberculosis and 1918 flu epidemics were largely successful. Specifically, public health officials' messaging framed the behavior of spitting as repulsive and endangering to others, prompting an elicitation of disgust. Anti-spitting campaigns - messaging that focuses on the threat of spit or sputum - have long been common during pandemics and manifested once again to combat the spread of COVID-19. Yet, few scholars have theorized if and how anti-spitting campaigns function to change behavior. One possibility is parasite stress theory, which posits that human behavior is driven by a desire to avoid pathogenic threats like spit. The application of these types of disgust appeals in public health messaging remains understudied and warrants exploration. To test the applicability of the parasite stress theory, our message experiment with US adults (N = 488) examined reactions to anti-spit messages that varied in visual disgust (low and high). For more highly educated respondents, the high disgust appeal directly decreased spitting intentions, and this relationship was stronger for individuals with higher levels of pathogen and moral disgust. Given the importance of public messaging during pandemics, future research should continue to examine the efficacy and theoretical underpinnings of specific disgust appeals.

Cancer Information Overload Across Time: Evidence from Two Longitudinal Studies.

A majority of U.S. adults report feeling overwhelmed by the amount of available cancer information, termed cancer information overload (CIO). Research has demonstrated CIO is prevalent and negatively related to health behaviors, but no study to date has examined this disposition across time. Two longitudinal studies - a colonoscopy intervention among older U.S. adults (N = 237) and an HPV vaccination intervention among young U.S. women (N = 411) - were utilized to examine CIO stability across time and its relationship to prevention intentions and indifference. CIO increased indifference for non-adherent individuals but had no effect on intentions. CIO was stable in study 1 but not study 2, suggesting CIO stabilizes across the life course. Results also support a five-item measure of CIO.

Visual Tailoring and Skin Cancer Prevention: Comparing Personalized, Stock, and Non-Ultraviolet Images.

Past research has demonstrated that ultraviolet (UV) photos - which reveal skin damage as dark patches - can increase preventive behaviors. Emerging camera technology facilitates personalized UV photos for interventions, yet little is known about how personalized photos compare to other visuals and what cognitive or affective mechanism explains their persuasive impact. To engage this research line, the current study compared the impact of personalized UV (PUV), stock UV (SUV), and non-UV (NUV) photos and, to advance theorizing on fear appeals, explored underlying affective mechanisms including physiological fear. A sample of 169 undergraduate students participated in a 3 (Visual conditions: PUV, SUV, NUV) × 2 (Efficacy conditions: No efficacy and Efficacy) between-participants message experiment on a computer equipped with iMotions 6.4 that tracked real-time physiological responses (facial expression and skin conductance). Results demonstrated that PUV skin damage photos produced significantly greater self-reported fear and positive valence (detected by facial expression analysis) than NUV and SUV visuals. Mediation analysis demonstrated that fear had a significant indirect effect on the relationship between exposure to PUV skin damage visuals and behavior expectations.

Communicating scientific uncertainty in the early stages of the COVID-19 pandemic: A message experiment.

The World Health Organization (WHO) officially declared COVID-19 a pandemic on March 11, 2020. It was a time of significant uncertainty as experts were not yet certain whether social distancing behaviors were necessary to slow the spread of the virus. Some public communicators opted to acknowledge uncertainty based on the limited evidence, whereas others downplayed uncertainty. This situation provided researchers with an opportunity to advance theory by explicating and testing cognitive responses to message uncertainty. Immediately following the WHO declaration (March 13-19, 2020), U.S. adults (N = 1186) were randomly assigned to one of six conditions in a 2 (message uncertainty: low, high) × 3 (argument support: expert, threat, precedent) between-participants experiment. Overall, perceived uncertainty negatively mediated the impact of message uncertainty on intentions. However, participant education was a key moderator. For those with more than a high school education, uncertain messages were related to higher intentions to social distance through increased critical reflection. For those with a high school education or less, uncertain messages were related to lower intentions through decreased message credibility.