Profiling SARS-CoV-2 HLA-I peptidome reveals T cell epitopes from out-of-frame ORFs

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Protease Activated Receptor-2 Contributes to Heart Failure

Heart failure is a major clinical problem worldwide. Previous studies have demonstrated an important role for G protein-coupled receptors, including protease-activated receptors (PARs), in the pathology of heart hypertrophy and failure. Activation of PAR-2 on cardiomyocytes has been shown to induce hypertrophic growth in vitro. PAR-2 also contributes to myocardial infarction and heart remodeling after ischemia/reperfusion injury. In this study, we found that PAR-2 induced hypertrophic growth of cultured rat neonatal cardiomyocytes in a MEK1/2 and p38 dependent manner. In addition, PAR-2 activation on mouse cardiomyocytes increased expression of the pro-fibrotic chemokine MCP-1. Furthermore, cardiomyocyte-specific overexpression of PAR-2 in mice induced heart hypertrophy, cardiac fibrosis, inflammation and heart failure. Finally, in a mouse model of myocardial infarction induced by permanent ligation of the left anterior descending coronary artery, PAR-2 deficiency attenuated heart remodeling and improved heart function independently of its contribution to the size of the initial infarct. Taken together, our data indicate that PAR-2 signaling contributes to the pathogenesis of hypertrophy and heart failure.     

Nuclear envelope‐associated dynein drives prophase centrosome separation and enables Eg5‐independent bipolar spindle formation

The microtubule motor protein kinesin‐5 (Eg5) provides an outward force on centrosomes, which drives bipolar spindle assembly. Acute inhibition of Eg5 blocks centrosome separation and causes mitotic arrest in human cells, making Eg5 an attractive target for anti‐cancer therapy. Using in vitro directed evolution, we show that human cells treated with Eg5 inhibitors can rapidly acquire the ability to divide in the complete absence of Eg5 activity. We have used these Eg5‐independent cells to study alternative mechanisms of centrosome separation. We uncovered a pathway involving nuclear envelope (NE)‐associated dynein that drives centrosome separation in prophase. This NE‐dynein pathway is essential for bipolar spindle assembly in the absence of Eg5, but also functions in the presence of full Eg5 activity, where it pulls individual centrosomes along the NE and acts in concert with Eg5‐dependent outward pushing forces to coordinate prophase centrosome separation. Together, these results reveal how the forces are produced to drive prophase centrosome separation and identify a novel mechanism of resistance to kinesin‐5 inhibitors.     

Structures of ascaroside aglycones

Free and derivatized aglycones and parent ascarosides of Ascaris lumbricoides and A. columnaris (Nematoda) were isolated by thin-layer and gas chromatography and analyzed by mass spectrometry and polarimetry. Results for monol aglycones confirmed previous chain-length assignments and the location of the l-hydroxyl group at C-2. The major monols of even carbon number possessed a methyl branch on the penultimate carbon (ω ? 1). Diol alycones were entirely unbranched homologues, mainly 31 and 33 carbons long, and had hydroxyl groups on C-2 and C-(ω ? 1). These aglycones were truly symmetrical, for they were optically inactive with the center bearing the glycone in diol ascaroside (C-2), being mostly or entirely the l configuration. Three major features of ascaroside structure—chain length composition of the aglycones, molecular weight of the unusual glycone (a dideoxyhexose), the kind and position of acyl groups—were clearly discernible in the spectra of intact ascarosides.     

Primary structure of an analog of crustacean pigment-dispersing hormone from the lubber grasshopper Romalea microptera

An octadecapeptide capable of inducing pigment dispersion in the chromatophores of the fiddler crab Uca pugilator has been isolated from lyophilized heads of the lubber grasshopper Romalea microptera. This pigment-dispersing factor (PDF) was purified by gel filtration, ion-exchange chromatography, partition chromatography, and reversed-phase high performance liquid chromatography. Automated gas-phase sequencing, followed by the identification of the carboxyl-terminal amide, established the primary structure of this PDF as Asn-Ser-Glu-Ile-Ile-Asn-Ser-Leu-Leu-Gly-Leu-Pro-Lys-Leu-Leu-Asn-Asp-Ala- NH2. This structure was confirmed by chemical synthesis and by demonstrating that the synthetic and native PDF displayed identical chromatographic behavior and biological activity. The Romalea PDF is structurally related to the crustacean pigment-dispersing hormones (PDHs), which are also octadecapeptides. The sequence of grasshopper PDF shows 78% homology with beta-PDH (from the crabs U. pugilator and Cancer magister) and 50% homology with alpha-PDH (from the prawn Pandalus borealis). This study provides the first direct chemical evidence for the structural relatedness of insect PDF to the crustacean PDHs, thus identifying them as an authentic family of arthropod peptides.     

Aging alterations in the modulation of central dopaminergic cilioinhibition by etorphine in the marine mussel,Mytilus edulis: Decrease in the inhibition of presynaptic dopamine release

1. This report further demonstrates that etorphine influences presynaptic dopamine release, which in turn centrally modulates peripheral cilioinhibition. 2. In older animals cilioinhibition has become enhanced due to a lack of responsiveness to endogenous opioids which results in greater dopamine release, causing a higher level of cilioinhibition as demonstrated by challenging the visceral ganglia with etorphine or destroying the dopaminergic component with 6-hydroxydopamine. 3. Only the central cilioinhibitory, not the peripheral inhibitory response, mechanism appears to be altered in older animals. Thus, the alteration appears in the central integrative mechanisms involved with regulating ciliary activity. 4. The KCl-stimulated release of dopamine is unaltered in both young and old organisms, whereas the opiate inhibition of the KCl-stimulated release of dopamine is reduced in older organisms. Thus, the aging-associated alteration is associated with a specific process. 5. The reduction of opioid influence and the resulting enhanced cilioinhibitory activity may make the organisms more susceptible to environmental stress.     

Changes in Epstein-Barr virus antibody titers associated with aging

Antibody titers to the Epstein-Barr virus (EBV), early antigen (EA) IgG, and virus capsid antigen (VCA) IgG and IgA, were measured in 44 geriatric subjects to determine if the depression in cellular immunity known to be associated with aging affects the expression of latent EBV. Similar assays were performed on plasma obtained from a young adult (medical student) population as a control group. We found that 89% of the geriatric samples were positive for EA IgG, and 83% of the plasma obtained from medical students were positive for EA IgG. One hundred percent of the geriatric subjects were positive for VCA IgG, and 87% of the medical students were positive for VCA IgG. Seven percent of the medical student blood samples were positive for VCA IgA; in contrast, 36% of the blood samples obtained from the geriatrics subjects were positive. Significant differences were also found in the geometric mean titers (GMT) of antibodies to EBV antigens; the GMT to EBV EA and VCA were significantly higher in the geriatric group. The data suggest that there may be some loss of control over latent EBV by the cellular immune response in geriatric individuals.     

Studies of the ferredoxin from Thermus thermophilus

The soluble ferredoxin from Thermus thermophilus was examined by M?ssbauer and EPR spectroscopies and by reductive titrations. These studies demonstrate the presence of one 3Fe center, responsible for the characteristic g = 2.02 EPR signal in the oxidized protein, and one [4Fe-4S] center which is responsible for the rhombic EPR spectrum of the fully reduced protein. These assignments should replace those made by Ohnishi et al. (Ohnishi, T., Blum, H., Sato, S., Nakazawa, K., Hon-nami, K., and Oshima, T. (1980) J. Biol. Chem. 255, 345-348) prior to the discovery of the 3Fe clusters. The amino acid composition was determined and is discussed with reference to recent structural studies of 7Fe ferredoxins.     

Equivalent Circuit of Frog Atrial Tissue as Determined by Voltage Clamp-Unclamp Experiments

The equivalent circuit that has been used in the analysis of nerve voltage-clamp data is that of the membrane capacity in parallel with the membrane resistance. Voltage-clamp experiments on frog atrial tissue indicate that this circuit will not suffice for this cardiac tissue. The change in membrane current associated with a step change in membrane potential does not show a rapid spike of capacitive current as would be expected for the simple parallel resistance-capacitance network. Rather, there is a step change in current followed by an exponential decay in current with a time constant of about 1 msec. This relatively slow capacitive charging current suggests that there is a resistance in series with the membrane capacity. A possible equivalent circuit is that of a series resistance external to the parallel resistance-capacitance network of the cell membranes. Another possible circuit assumes that the series resistance is an integral part of the cell membrane. The data presented in this paper demonstrate that the equivalent circuit of a bundle of frog atrial muscle is that of an external resistance in series with the cell membranes.