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Palmitoleic acid (POA), a nonessential, monounsaturated omega-7 fatty acid (C16:1n7), is a lipid hormone secreted from adipose tissue and has beneficial effects on distant organs, such as the liver and muscle. Interestingly, POA decreases lipogenesis in toxic storage sites such as the liver and muscle, and paradoxically increases lipogenesis in safe storage sites, such as adipose tissue. Furthermore, higher POA levels in humans are correlated with better insulin sensitivity, an improved lipid profile, and a lower incidence of type-2 diabetes and cardiovascular pathologies, such as myocardial infarction. In preclinical animal models, POA improves glucose intolerance, dyslipidemia, and steatosis of the muscle and liver, while improving insulin sensitivity and secretion. This double-blind placebo-controlled clinical trial tests the hypothesis that POA increases insulin sensitivity and decreases hepatic lipogenesis in overweight and obese adult subjects with pre-diabetes. Important to note, that this is the first study ever to use pure (>90%) POA with < 0.3% palmitic acid (PA), which masks the beneficial effects of POA. The possible positive findings may offer a therapeutic and/or preventative pathway against diabetes and related immunometabolic diseases., Competing Interests: MB has a grant funding and a consulting agreement as a scientific advisor role in Tersus Life Sciences, the study sponsor. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Cetin, Pedersen, Porter, Adler and Burak.)

Cigarette smoking has many serious negative health consequences. The relationship between smoking and SARS-CoV-2 infection is controversial, specifically whether smokers are at increased risk of infection. We investigated the impact of cigarette smoke on ACE2 isoform expression and SARS-CoV-2 infection in differentiated primary human bronchial epithelial cells at the air-liquid-interface (ALI). We assessed the expression of ACE2 in response to CSE and therapeutics reported to modulate ACE2. We exposed ALI cultures to cigarette smoke extract (CSE) and then infected them with SARS-CoV-2. We measured cellular infection using flow cytometry and whole-transwell immunofluorescence. We found that CSE increased expression of full-length ACE2 (flACE2) but did not alter the expression of a Type I-interferon sensitive truncated isoform (dACE2) that lacks the capacity to bind SARS-CoV-2. CSE did not have a significant impact on key mediators of the innate immune response. Importantly, we show that, despite the increase in flACE2, CSE did not alter airway cell infection after CSE exposure. We found that nicotine does not significantly alter flACE2 expression but that NRF2 agonists do lead to an increase in flACE2 expression. This increase was not associated with an increase in SARS-CoV-2 infection. Our results are consistent with the epidemiological data suggesting that current smokers do not have an excess of SARS-CoV-2 infection. but that those with chronic respiratory or cardiovascular disease are more vulnerable to severe COVID-19. They suggest that, in differentiated conducting airway cells, flACE2 expression levels may not limit airway SARS-CoV-2 infection., Competing Interests: The authors declare no conflict of interest., (Crown Copyright © 2023 Published by Elsevier Ltd.)

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use.

Background: Quantitative proteomics is able to provide a comprehensive, unbiased description of changes to cells caused by viral infection, but interpretation may be complicated by differential changes in infected and uninfected 'bystander' cells, or the use of non-physiological cellular models. Methods: In this paper, we use fluorescence-activated cell sorting (FACS) and quantitative proteomics to analyse cell-autonomous changes caused by authentic SARS-CoV-2 infection of respiratory epithelial cells, the main target of viral infection in vivo . First, we determine the relative abundance of proteins in primary human airway epithelial cells differentiated at the air-liquid interface (basal, secretory and ciliated cells). Next, we specifically characterise changes caused by SARS-CoV-2 infection of ciliated cells. Finally, we compare temporal proteomic changes in infected and uninfected 'bystander' Calu-3 lung epithelial cells and compare infection with B.29 and B.1.1.7 (Alpha) variants. Results: Amongst 5,709 quantified proteins in primary human airway ciliated cells, the abundance of 226 changed significantly in the presence of SARS-CoV-2 infection (q <0.05 and >1.5-fold). Notably, viral replication proceeded without inducing a type-I interferon response. Amongst 6,996 quantified proteins in Calu-3 cells, the abundance of 645 proteins changed significantly in the presence of SARS-CoV-2 infection (q < 0.05 and > 1.5-fold). In contrast to the primary cell model, a clear type I interferon (IFN) response was observed. Nonetheless, induction of IFN-inducible proteins was markedly attenuated in infected cells, compared with uninfected 'bystander' cells. Infection with B.29 and B.1.1.7 (Alpha) variants gave similar results. Conclusions: Taken together, our data provide a detailed proteomic map of changes in SARS-CoV-2-infected respiratory epithelial cells in two widely used, physiologically relevant models of infection. As well as identifying dysregulated cellular proteins and processes, the effectiveness of strategies employed by SARS-CoV-2 to avoid the type I IFN response is illustrated in both models., Competing Interests: No competing interests were disclosed., (Copyright: © 2022 Crozier TWM et al.)

Background: There are limited effective prophylactic/early treatments for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Viral entry requires spike protein binding to the angiotensin-converting enzyme-2 receptor and cleavage by transmembrane serine protease 2 (TMPRSS2), a cell surface serine protease. Targeting of TMPRSS2 by either androgen blockade or direct inhibition is in clinical trials in early SARS-CoV-2 infection., Methods: We used differentiated primary human airway epithelial cells at the air-liquid interface to test the impact of targeting TMPRSS2 on the prevention of SARS-CoV-2 infection., Results: We first modelled the systemic delivery of compounds. Enzalutamide, an oral androgen receptor antagonist, had no impact on SARS-CoV-2 infection. By contrast, camostat mesylate, an orally available serine protease inhibitor, blocked SARS-CoV-2 entry. However, oral camostat is rapidly metabolised in the circulation, with poor airway bioavailability. We therefore modelled local airway administration by applying camostat to the apical surface of differentiated airway cultures. We demonstrated that a brief exposure to topical camostat effectively restricts SARS-CoV-2 infection., Conclusion: These experiments demonstrate a potential therapeutic role for topical camostat for pre- or post-exposure prophylaxis of SARS-CoV-2, which can now be evaluated in a clinical trial., (© 2022 Guo et al.)

Background: Protease inhibitors (PIs) are important regulators of physiology and represent anti-parasitic druggable and vaccine targets. We conducted bioinformatic analyses of genome and transcriptome data to determine the protease inhibitor (PI) repertoire in Amblyomma americanum and in 25 other ixodid tick species. For A. americanum, we compared the PI repertoires in fed and unfed, male and female A. americanum ticks. We also analyzed PI repertoires of female 48, 96 and 120 h-fed midgut (MG) and salivary gland (SG) tissues., Results: We found 1,595 putative non-redundant PI sequences across 26 ixodid tick species. Ticks express PIs from at least 18 different families: I1, I2, I4, I8, I21, I25, I29, I31, I32, I35, I39, I43, I51, I53, I63, I68, I72 and I74 (MEROPS). The largest PI families were I2, I4 and I8 and lowest in I21, I31, I32, I35 and I68. The majority (75%) of tick PIs putatively inhibit serine proteases, with ~11 and 9% putatively regulating cysteine or metalloprotease-mediated pathways, respectively, and ~4% putatively regulating multiple/mixed protease types. In A. americanum, we found 370 PIs in female and 354 in male ticks. In A. americanum we found 231 and 442 in unfed and fed ticks, respectively. In females, we found 206 and 164 PIs in SG and MG, respectively. The majority of highly cross-tick species conserved PIs were in families I1, I2, I8, I21, I25, I29, I39 and I43., Conclusions: Ticks appear to express large and diverse repertoires of PIs that primarily target serine protease-mediated pathways. We speculate that PI families with the highest repertoires may contain functionally redundant members while those with the lowest repertoires are functionally non-redundant PIs. We found some highly conserved PIs in the latter category, which we propose as potential candidates for broad-spectrum anti-tick vaccine candidates or druggable targets in tick control.

Background: Multiple tick saliva proteins, the majority of which are unknown, confer tick resistance in repeatedly infested animals. The objective of this study was to identify the 24-48 h fed Amblyomma americanum tick saliva immuno-proteome. The 24-48 h tick-feeding phase is critical to tick parasitism as it precedes important events in tick biology, blood meal feeding and disease agent transmission. Fed male, 24 and 96 h fed female phage display cDNA expression libraries were biopanned using rabbit antibodies to 24 and 48 h fed A. americanum female tick saliva proteins. Biopanned immuno-cDNA libraries were subjected to next generation sequencing, de novo assembly, and bioinformatic analysis., Results: More than 800 transcripts that code for 24-48 h fed A. americanum immuno-proteins are described. Of the 895 immuno-proteins, 52% (464/895) were provisionally identified based on matches in GenBank. Of these, ~19% (86/464) show high level of identity to other tick hypothetical proteins, and the rest include putative proteases (serine, cysteine, leukotriene A-4 hydrolase, carboxypeptidases, and metalloproteases), protease inhibitors (serine and cysteine protease inhibitors, tick carboxypeptidase inhibitor), and transporters and/or ligand binding proteins (histamine binding/lipocalin, fatty acid binding, calreticulin, hemelipoprotein, IgG binding protein, ferritin, insulin-like growth factor binding proteins, and evasin). Others include enzymes (glutathione transferase, cytochrome oxidase, protein disulfide isomerase), ribosomal proteins, and those of miscellaneous functions (histamine release factor, selenoproteins, tetraspanin, defensin, heat shock proteins)., Conclusions: Data here demonstrate that A. americanum secretes a complex cocktail of immunogenic tick saliva proteins during the first 24-48 h of feeding. Of significance, previously validated immunogenic tick saliva proteins including AV422 protein, calreticulin, histamine release factor, histamine binding/lipocalins, selenoproteins, and paramyosin were identified in this screen, supporting the specificity of the approach in this study. While descriptive, this study opens opportunities for in-depth tick feeding physiology studies.

Cardiac ATP-sensitive K+ (K(ATP)) channels are formed by Kir6.2 and SUR2A subunits. We produced transgenic mice that express dominant negative Kir6.x pore-forming subunits (Kir6.1-AAA or Kir6.2-AAA) in cardiac myocytes by driving their expression with the alpha-myosin heavy chain promoter. Weight gain and development after birth of these mice were similar to nontransgenic mice, but an increased mortality was noted after the age of 4-5 mo. Transgenic mice lacked cardiac K(ATP) channel activity as assessed with patch clamp techniques. Consistent with a decreased current density observed at positive voltages, the action potential duration was increased in these mice. Some myocytes developed EADs after isoproterenol treatment. Hemodynamic measurements revealed no significant effects on ventricular function (apart from a slightly elevated heart rate), whereas in vivo electrophysiological recordings revealed a prolonged ventricular effective refractory period in transgenic mice. The transgenic mice tolerated stress less well as evident from treadmill stress tests. The proarrhythmogenic features and lack of adaptation to a stress response in transgenic mice suggest that these features are intrinsic to the myocardium and that K(ATP) channels in the myocardium have an important role in protecting the heart from lethal arrhythmias and adaptation to stress situations.