Role of Virally-Encoded Deubiquitinating Enzymes in Regulation of the Virus Life Cycle.

The ubiquitin (Ub) proteasome system (UPS) plays a pivotal role in regulation of numerous cellular processes, including innate and adaptive immune responses that are essential for restriction of the virus life cycle in the infected cells. Deubiquitination by the deubiquitinating enzyme, deubiquitinase (DUB), is a reversible molecular process to remove Ub or Ub chains from the target proteins. Deubiquitination is an integral strategy within the UPS in regulating survival and proliferation of the infecting virus and the virus-invaded cells. Many viruses in the infected cells are reported to encode viral DUB, and these vial DUBs actively disrupt cellular Ub-dependent processes to suppress host antiviral immune response, enhancing virus replication and thus proliferation. This review surveys the types of DUBs encoded by different viruses and their molecular processes for how the infecting viruses take advantage of the DUB system to evade the host immune response and expedite their replication.

Large-Scale Assembly of Peptide-Based Hierarchical Nanostructures and Their Antiferroelectric Properties.

An effective strategy is developed to create peptide-based hierarchical nanostructures through the meniscus-driven self-assembly in a large area and fabricate antiferroelectric devices based on these nanostructures for the first time. The diphenylalanine hierarchical nanostructures (FF-HNs) are self-assembled by vertically pulling a substrate from a diphenylalanine (FF) solution dissolved in a miscible solvent under precisely controlled conditions. Owing to the unique structural properties of FF nanostructures, including high crystallinity and α-helix structures, FF-HNs possess a net electrical dipole moment, which can be switched in an external electric field. The mass production of antiferroelectric devices based on FF-HNs can be successfully achieved by means of this biomimetic assembly technique. The devices show an evident antiferroelectric to ferroelectric transition under dark conditions, while the ferroelectricity is found to be tunable by light. Notably, it is discovered that the modulation of antiferroelectric behaviors of FF-HNs under glutaraldehyde exposure is due to the FF molecules that are transformed into cyclophenylalanine by glutaraldehyde. This work provides a stepping stone toward the mass production of self-assembled hierarchical nanostructures based on biomolecules as well as the mass fabrication of electronic devices based on biomolecular nanostructures for practical applications.

Electroluminescent soft elastomer actuators with adjustable luminance and strain.

We demonstrate a multifunctional soft actuator that exhibits both electroluminescence (EL) and soft actuation with a strain of 85% and a maximum luminance of 300 cd m-2, superior to previous devices with individual functions. This was possible by combining several strategies such as the development of highly conductive, transparent, and stretchable electrodes, incorporation of high-k nanoparticles to increase the electric field applied to the EL particles, and application of AC + DC composite signals to simplify the device structure. We expect this research to contribute to the development of new soft devices that can further enhance human-machine interactions in color displaying actuator applications.

Role of the Ubiquitin Proteasome System (UPS) in the HIV-1 Life Cycle.

Given that the ubiquitin proteasome system (UPS) is the major protein degradation process in the regulation of a wide variety of cellular processes in eukaryotic cells, including alteration of cellular location, modulation of protein activity, and regulation of protein interaction, it is reasonable to suggest that the infecting HIV-1 and the invaded hosts exploit the UPS in a contest for survival and proliferation. However, to date, regulation of the HIV-1 life cycle has been mainly explained by the stage-specific expression of HIV-1 viral genes, not by elimination processes of the synthesized proteins after completion of their duties in the infected cells, which is also quintessential for understanding the molecular processes of the virus life cycle and thereby HIV-1 pathogenesis. In fact, several previous publications have indicated that the UPS plays a critical role in the regulation of the proteasomal degradation of viral and cellular counterparts at every step of the HIV-1 life cycle, from the virus entry to release of the assembled virus particles, which is integral for the regulation of survival and proliferation of the infecting HIV-1 and to replication restriction of the invading virus in the host. However, it is unknown whether and how these individual events taking place at different stages of the HIV-1 life cycle are orchestrated as an overall strategy to overcome the restrictions conferred by the host cells. Thus, in this review, we overview the interplay between HIV-1 viral and cellular proteins for restrictions/competitions for proliferation of the virus in the infected cell, which could open a new avenue for the development of therapeutics against HIV-1 via targeting a specific step of the proteasome degradation pathway during the HIV-1 life cycle.

Suppression of HIV-1 Nef translation by Sam68 mutant-induced stress granules and nef mRNA sequestration.

HIV-1 Nef plays important roles in HIV-1 replication and pathogenesis. It is translated from completely spliced HIV-1 RNA, and its expression is inherently regulated at the levels of viral DNA transcription and RNA splicing. Here we show that Sam68 cytoplasmic mutants potently suppress Nef expression. The suppression requires Sam68 domain aa 269-321 and is correlated with its ability to induce stress granules. In addition, the suppression is specific to Nef, and direct binding to nef mRNA 3'UTR confers the suppression specificity. Furthermore, nef mRNA is targeted to and enriched in these induced stress granules. Importantly, Nef suppression occurs in the context of HIV-1 infection of CD4+ T lymphocytes with little MHC I and CD4 downregulation. Taken together, these results demonstrate that stress granule induction and nef mRNA sequestration account for this translational suppression of Nef expression and offer a strategy for development of anti-HIV therapeutics to buttress our fight against HIV/AIDS.

Interaction between Nef and INI1/SMARCB1 augments replicability of HIV-1 in resting human peripheral blood mononuclear cells.

A central feature of HIV-1 infection is the inability of entering virus to integrate into chromosomes of resting T lymphocytes unless they are mitogenically activated. In contrast, SIVpbj1.9 replicates in initially resting T lymphocytes by activating infected cells. Previous reports have shown that a difference in Nef-mediated T cell activation between HIV-1 and SIVpbj1.9 plays a critical role in the differing abilities of these viruses to replicate in resting lymphocytes. However, the molecular details of these differences are still unclear. Here, we show that infection with a chimeric virus, HSIVnef, which harbors the 5' 308 nucleotides of SIVpbj1.9 nef in place of the 5' 221 nucleotides of HIV-1 nef in the HIV-1 proviral backbone, resulted in integration of the provirus into host chromosomes without mitogenic activation and thereby replication in resting human PBMCs (hPBMCs). These results indicate that Nef is an essential viral determinant for the integration of provirus into host chromosomes in resting T cells. Using the yeast two-hybrid system, we identified integrase interactor-1 (INI1/SMARCB1) as a cellular factor that is involved in the integration process via interaction with Nef. Although INI1 interacted with both SIVpbj1.9 and HIV-1 Nefs, SIVpbj1.9 Nef, but not HIV-1 Nef, enhanced proviral integration into host DNA. Furthermore, mutational analysis revealed that the basic-amino-acid-rich amino-terminal domain in SIVpbj1.9 Nef is crucial for interaction with INI1 and virus replication in resting hPBMCs. Taken together, these data indicate that Nef is a critical viral protein for incorporating nascent proviral DNA into host chromosomes in resting PBMCs and that this occurs through interaction with INI1. This elucidates the basis for replication of the integrated provirus when the host cell is in a resting state.

Comparative molecular genetic analysis of simian and human HIV-1 integrase interactor INI1/SMARCB1/SNF5.

Human integrase interactor 1 (INI1/SMARCB1/SNF5) is a chromatin-remodeling molecule that binds to HIV-1 integrase and enhances proviral DNA integration. INI1 is also known as a tumor suppressor gene and has been found to be mutated in several aggressive tumors such as rhabdoid and lymphoid tumors. To study the function of simian INI1, we screened and cloned simian INI1 cDNA from B lymphoma cells of rhesus monkeys using RT-PCR. Sequence analysis showed 23 single nucleotide differences compared to the human ortholog, which, however, did not result in amino acid changes, and the amino acid sequence is therefore 100% conserved between human and simian INI1. Two alternatively spliced isoforms, INI1a and INI1b, were also found in simian INI1. These two isoforms did not show any functional difference in HIV-1 proviral DNA integration and nuclear localization, suggesting that the specificity of simian INI1 would not be a factor preventing HIV-1 infection of a simian host. Nevertheless, INI1b is expressed only in established cancer cell lines such as Jurkat and COS-7 cells, and not in primary cells, suggesting that INIlb could be an indicator of cell transformation.

Impact of Annexin A2 on virus life cycles.

Due to the limited size of viral genomes, hijacking host machinery by the viruses taking place throughout the virus life cycle is inevitable for the survival and proliferation of the virus in the infected hosts. Recent reports indicated that Annexin A2 (AnxA2), a calcium- and lipid-binding cellular protein, plays an important role as a critical regulator in various steps of the virus life cycle. The multifarious AnxA2 functions in cells, such as adhesion, adsorption, endocytosis, exocytosis, cell proliferation and division, inflammation, cancer metastasis, angiogenesis, etc., are intimately related to the various clinical courses of viral infection. Ubiquitous expression of AnxA2 across multiple cell types indicates the broad range of susceptibility of diverse species of the virus to induce disparate viral disease in various tissues, and intracellular expression of AnxA2 in the cytoplasmic membrane, cytosol, and nucleus suggests the involvement of AnxA2 in the regulation of the different stages of various virus life cycles within host cells. However, it is yet unclear as to the molecular processes on how AnxA2 and the infected virus interplay to regulate virus life cycles and thereby the virus-associated disease courses, and hence elucidation of the molecular mechanisms on AnxA2-mediated virus life cycle will provide essential clues to develop therapeutics deterring viral disease.

Pediatric mandibular chronic nonbacterial osteomyelitis: A case report with 12 years of radiologic follow-up.

Chronic nonbacterial osteomyelitis (CNO) is histologically characterized by nonspecific osteitis. This inflammatory disorder, which lacks an infectious origin, typically presents with chronic pain and swelling at the affected site that can persist for months or even years. However, it is rare for CNO to affect the mandible. A 10-year-old girl presented with a primary complaint of pain in her left mandible. She had no significant medical or dental history. On examination, swelling was visible on the left buccal side, and imaging revealed radiolucent bone deterioration within the left mandible. This case report presents the radiological changes observed over a 12-year follow-up period. Variations in radiopacity, radiolucency, and periosteal reactions were noted periodically. This case highlights the radiological characteristics and findings that are crucial for the diagnosis of CNO, a condition for which no clear diagnostic criteria are currently available.

HIV-1 Nef-mediated T-cell activation and chemotaxis are decoupled using a HIV-1/SIVpbj1.9. chimeric nef variant.

HIV-1 Nef is known to activate CD4+ T cells but inhibit their migration toward SDF-1α. However, it is not clear how this protein orchestrates these two seemingly concomitant events. In this study, by comparing these two activities of HIV-1 Nef with those of its primate counterpart, SIVpbj1.9, we found that HIV-1 Nef activated T cells only in the presence of CD3/ CD28 stimulation, while SIVpbj1.9 Nef did even without CD3/CD28. We also observed that HIV-1 Nef inhibited T-cell chemotaxis toward SDF-1α, while SIVpbj1.9 Nef did not. A hybrid between HIV-1 and SIVpbj1.9 Nef completely abrogated the chemotaxis blockade by HIV-1 Nef while failing to activate T cells without CD3/CD28 co-stimulation. Mutations in the myristoylation and SH3-binding site, but not the basic-rich domain, in Nef were unresponsive to CD3/CD28 stimulation but reversed the inhibition of migration. These findings indicate that the signals for T-cell activation by Nef do not necessarily parallel those for T-cell migration.

Ubiquitin-protein ligase E3A (UBE3A) mediation of viral infection and human diseases.

The Ubiquitin-protein ligase E3A, UBE3A, also known as E6-associated protein (E6-AP), is known to play an essential role in regulating the degradation of various proteins by transferring Ub from E2 Ub conjugating enzymes to the substrate proteins. Several studies indicate that UBE3A regulates the stabilities of key viral proteins in the virus-infected cells and, thereby, the infected virus-mediated diseases, even if it were reported that UBE3A participates in non-viral-related human diseases. Furthermore, mutations such as deletions and duplications in the maternally inherited gene in the brain cause human neurodevelopmental disorders such as Angelman syndrome (AS) and autism. It is also known that UBE3A functions as a transcriptional coactivator for the expression of steroid hormone receptors. These reports establish that UBE3A is distinguished by its multitudinous functions that are paramount to viral pathology and human diseases. This review is focused on molecular mechanisms for such intensive participation of UBE3A in disease formation and virus regulation.

Novel role of HIV-1 Nef in regulating the ubiquitination of cellular proteins.

Our recent data established that HIV-1 Nef is pivotal in determining the fate of cellular proteins by modulating ubiquitination. However, it is unknown which proteins are ubiquitinated in the presence of Nef, a question critical for understanding the proliferation/restriction strategies of HIV-1 in infected cells. To identify cellular proteins ubiquitinated by Nef, we conducted a proteomic analysis of cellular proteins in the presence and absence of Nef. Proteomic analysis in HEK293T cells indicated that 93 proteins were upregulated and 232 were downregulated in their ubiquitination status by Nef. Computational analysis classified these proteins based on molecular function, biological process, subcellular localization, and biological pathway. Of those proteins, we found a majority of molecular functions to be involved in binding and catalytic activity. With respect to biological processes, a significant portion of the proteins identified were related to cellular and metabolic processes. Subcellular localization analysis showed the bulk of proteins to be localized to the cytosol and cytosolic compartments, which is consistent with the known function and location of Nef during HIV-1 infection. As for biological pathways, the wide range of affected proteins was denoted by the multiple modes to fulfill function, as distinguished from a strictly singular means, which was not detected. Among these ubiquitinated proteins, six were found to directly interact with Nef, wherein two were upregulated and four downregulated. We also identified 14 proteins involved in protein stability through directly participating in the Ubiquitin Proteasome System (UPS)-mediated proteasomal degradation pathway. Of those proteins, we found six upregulated and eight downregulated. Taken together, these analyses indicate that HIV-1 Nef is integral to regulating the stability of various cellular proteins via modulating ubiquitination. The molecular mechanisms directing Nef-triggered regulation of cellular protein ubiquitination are currently under investigation.

HIV-1-Mediated Acceleration of Oncovirus-Related Non-AIDS-Defining Cancers.

With the advent of combination antiretroviral therapy (cART), overall survival has been improved, and the incidence of acquired immunodeficiency syndrome (AIDS)-defining cancers has also been remarkably reduced. However, non-AIDS-defining cancers among human immunodeficiency virus-1 (HIV-1)-associated malignancies have increased significantly so that cancer is the leading cause of death in people living with HIV in certain highly developed countries, such as France. However, it is currently unknown how HIV-1 infection raises oncogenic virus-mediated cancer risks in the HIV-1 and oncogenic virus co-infected patients, and thus elucidation of the molecular mechanisms for how HIV-1 expedites the oncogenic viruses-triggered tumorigenesis in the co-infected hosts is imperative for developing therapeutics to cure or impede the carcinogenesis. Hence, this review is focused on HIV-1 and oncogenic virus co-infection-mediated molecular processes in the acceleration of non-AIDS-defining cancers.

A Non-Canonical Role for IRE1α Links ER and Mitochondria as Key Regulators of Astrocyte Dysfunction: Implications in Methamphetamine use and HIV-Associated Neurocognitive Disorders.

Astrocytes are one of the most numerous glial cells in the central nervous system (CNS) and provide essential support to neurons to ensure CNS health and function. During a neuropathological challenge, such as during human immunodeficiency virus (HIV)-1 infection or (METH)amphetamine exposure, astrocytes shift their neuroprotective functions and can become neurotoxic. Identifying cellular and molecular mechanisms underlying astrocyte dysfunction are of heightened importance to optimize the coupling between astrocytes and neurons and ensure neuronal fitness against CNS pathology, including HIV-1-associated neurocognitive disorders (HAND) and METH use disorder. Mitochondria are essential organelles for regulating metabolic, antioxidant, and inflammatory profiles. Moreover, endoplasmic reticulum (ER)-associated signaling pathways, such as calcium and the unfolded protein response (UPR), are important messengers for cellular fate and function, including inflammation and mitochondrial homeostasis. Increasing evidence supports that the three arms of the UPR are involved in the direct contact and communication between ER and mitochondria through mitochondria-associated ER membranes (MAMs). The current study investigated the effects of HIV-1 infection and chronic METH exposure on astrocyte ER and mitochondrial homeostasis and then examined the three UPR messengers as potential regulators of astrocyte mitochondrial dysfunction. Using primary human astrocytes infected with pseudotyped HIV-1 or exposed to low doses of METH for 7 days, astrocytes had increased mitochondrial oxygen consumption rate (OCR), cytosolic calcium flux and protein expression of UPR mediators. Notably, inositol-requiring protein 1α (IRE1α) was most prominently upregulated following both HIV-1 infection and chronic METH exposure. Moreover, pharmacological inhibition of the three UPR arms highlighted IRE1α as a key regulator of astrocyte metabolic function. To further explore the regulatory role of astrocyte IRE1α, astrocytes were transfected with an IRE1α overexpression vector followed by activation with the proinflammatory cytokine interleukin 1ß. Overall, our findings confirm IRE1α modulates astrocyte mitochondrial respiration, glycolytic function, morphological activation, inflammation, and glutamate uptake, highlighting a novel potential target for regulating astrocyte dysfunction. Finally, these findings suggest both canonical and non-canonical UPR mechanisms of astrocyte IRE1α. Thus, additional studies are needed to determine how to best balance astrocyte IRE1α functions to both promote astrocyte neuroprotective properties while preventing neurotoxic properties during CNS pathologies.

Sex-difference in air pollution-related acute circulatory and respiratory mortality and hospitalization.

BACKGROUND: Numerous studies have estimated adverse effects of short-term exposure to ambient air pollution on public health. Few have focused on sex-differences, and results have been inconsistent. The purpose of this study was three-fold: to identify sex-differences in air pollution-related health outcomes; to examine sex-differences by cause and season; and to examine time trends in sex-differences. METHODS: Daily data were collected on circulatory- and respiratory-related mortality (for 29 years) and cause-specific hospitalization (for 17 years) with hourly concentrations of ozone (O3), nitrogen dioxide (NO2), and fine particulate matter (PM2.5). For hospitalization, more specific causes were examined: ischemic heart disease (IHD), other heart disease (OHD), cerebrovascular disease (CEV), chronic lower respiratory diseases (CLRD), and Influenza/Pneumonia (InfPn). Generalized Poisson models were applied to 24 Canadian cities, and the city-specific estimates were combined for nationwide estimates for each sex using Bayesian hierarchical models. Finally, sex-differences were tested statistically based on their interval estimates, considering the correlation between sex-specific national estimates. RESULTS: Sex-differences were more frequently observed for hospitalization than mortality, respiratory than circulatory health outcomes, and warm than cold season. For hospitalization, males were at higher risk (M > F) for warm season (OHD and InfPn from O3; IHD from NO2; and InfPn from PM2.5), but F > M for cold season (CEV from O3 and OHD from NO2). For mortality, we found F > M only for circulatory diseases from ozone during the warm season. Among the above-mentioned sex-differences, three cases showed consistent time trends over the years: while M > F for OHD from O3 and IHD from NO2, F > M for OHD from NO2. CONCLUSIONS: We found that sex-differences in effect of ambient air pollution varied over health outcome, cause, season and time. In particular, the consistent trends (either F > M or M > F) across 17 years provide stronger evidence of sex-differences in hospitalizations, and warrant investigation in other populations.

Cal'MAM'ity at the Endoplasmic Reticulum-Mitochondrial Interface: A Potential Therapeutic Target for Neurodegeneration and Human Immunodeficiency Virus-Associated Neurocognitive Disorders.

The endoplasmic reticulum (ER) is a multifunctional organelle and serves as the primary site for intracellular calcium storage, lipid biogenesis, protein synthesis, and quality control. Mitochondria are responsible for producing the majority of cellular energy required for cell survival and function and are integral for many metabolic and signaling processes. Mitochondria-associated ER membranes (MAMs) are direct contact sites between the ER and mitochondria that serve as platforms to coordinate fundamental cellular processes such as mitochondrial dynamics and bioenergetics, calcium and lipid homeostasis, autophagy, apoptosis, inflammation, and intracellular stress responses. Given the importance of MAM-mediated mechanisms in regulating cellular fate and function, MAMs are now known as key molecular and cellular hubs underlying disease pathology. Notably, neurons are uniquely susceptible to mitochondrial dysfunction and intracellular stress, which highlights the importance of MAMs as potential targets to manipulate MAM-associated mechanisms. However, whether altered MAM communication and connectivity are causative agents or compensatory mechanisms in disease development and progression remains elusive. Regardless, exploration is warranted to determine if MAMs are therapeutically targetable to combat neurodegeneration. Here, we review key MAM interactions and proteins both in vitro and in vivo models of Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. We further discuss implications of MAMs in HIV-associated neurocognitive disorders (HAND), as MAMs have not yet been explored in this neuropathology. These perspectives specifically focus on mitochondrial dysfunction, calcium dysregulation and ER stress as notable MAM-mediated mechanisms underlying HAND pathology. Finally, we discuss potential targets to manipulate MAM function as a therapeutic intervention against neurodegeneration. Future investigations are warranted to better understand the interplay and therapeutic application of MAMs in glial dysfunction and neurotoxicity.

The Perfect Storm: COVID-19 Health Disparities in US Blacks.

Coronavirus disease 2019 (COVID-19) accounts for over 180,000 deaths in the USA. Although COVID-19 affects all racial ethnicities, non-Hispanic Blacks have the highest mortality rates. Evidence continues to emerge, linking the disproportion of contagion and mortality from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a result of adverse social determinants of health. Yet, genetic predisposition may also play a credible role in disease transmission. SARS-CoV-2 enters cells by interaction between SARS-CoV-2 spike protein and the receptor molecule angiotensin converting enzyme 2 (ACE2) expressed on the surface of the target cells, such that polymorphisms and the expression level of ACE2 influence infectivity and consequent pathogenesis of SARS-CoV-2. Genetic polymorphisms in other multiple genes, such as acetylcholinesterase (AChE) and interleukin-6, are also closely associated with underlying diseases, such as hypertension and type 2 diabetes mellitus, which substantially raise SARS-CoV-2 mortality. However, it is unknown how these genetic polymorphisms contribute to the disparate mortality rates, with or without underlying diseases. Of particular interest is the potential that genetic polymorphisms in these genes may be influencing the disparity of COVID-19 mortality rates in Black communities. Here, we review the evidence that biological predisposition for high-risk comorbid conditions may be relevant to our ability to fully understand and therefore address health disparities of COVID-19 deaths in Blacks.

The Many Faces of Innate Immunity in SARS-CoV-2 Infection.

The innate immune system is important for initial antiviral response. SARS-CoV-2 can result in overactivity or suppression of the innate immune system. A dysregulated immune response is associated with poor outcomes; with patients having significant Neutrophil-to-Lymphocyte ratios (NLR) due to neutrophilia alongside lymphopenia. Elevated interleukin (IL)-6 and IL-8 leads to overactivity and is a prominent feature of severe COVID-19 patients. IL-6 can result in lymphopenia; where COVID-19 patients typically have significantly altered lymphocyte subsets. IL-8 attracts neutrophils; which may play a significant role in lung tissue damage with the formation of neutrophil extracellular traps leading to cytokine storm or acute respiratory distress syndrome. Several factors like pre-existing co-morbidities, genetic risks, viral pathogenicity, and therapeutic efficacy act as important modifiers of SARS-CoV-2 risks for disease through an interplay with innate host inflammatory responses. In this review, we discuss the role of the innate immune system at play with other important modifiers in SARS-CoV-2 infection.

Long term clinical result of implant induced injury on the adjacent tooth.

The purpose of the retrospective study was to investigate the long-term result of implant-induced injury on the adjacent tooth. The subjects of this retrospective study were patients who had received implants and had tooth injury; direct invasion of root (group I), root surface contact (group II), or < 1 mm distance of the implant from the root (group III). Clinical and pathological changes were periodically examined using radiographs and intra-oral examinations. Paired t-tests and chi-square tests were used to evaluate the implant stability quotient (ISQ) of implant and tooth complications, respectively (α = 0.05). A total of 32 implants and teeth in 28 patients were observed for average 122.7 (± 31.7, minimum 86) months. Seven teeth, three of which were subsequently extracted, needed root canal treatment. Finally, 90.6% of the injured teeth remained functional. Complications were significant and varied according to the group, with group I showing higher events than the others. The ISQs increased significantly. One implant in group I resulted in osseointegration failure. The implant survival rate was 96.9%. In conclusion, it was found even when a tooth is injured by an implant, immediate extraction is unnecessary, and the osseointegration of the invading implant is also predictable.