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Despite advancements in medical research, androgenetic alopecia (AGA) remains a humankind problem that still needs to be overcome. To date, clinical practice lacks an ideal treatment for AGA. The Wnt/ß-catenin signaling pathway is evidenced to play a key role in hair regrowth, hence, modulating this signaling pathway for AGA therapy appears to be rational. One of the major inhibitors of the canonical Wnt/ß-catenin signaling pathway is dickkopf-related protein 1 (DKK1). In this report, we have selected a small interfering RNA (siRNA) targeting DKK1 in vitro via qPCR and then tested its efficacy in vivo on the depilated dorsal skin of the mice. The changes in hair growth in different groups were observed over time. Moreover, the visual observation of the hair growth and hematoxylin and eosin (HE) staining showed that DKK1-targeting siRNA reveals non-inferior results compared with the mice treated with the Food and Drug Administration (FDA)-approved, commercially available minoxidil (5%) topical solution that was used as a positive control. Both- positive control and DKK1-targeting siRNA groups demonstrated significantly superior results compared with the control group that received negative control siRNA. Consequently, siRNAs targeting DKK1 may promote hair growth regulation in the AGA population via potentially activating the Wnt/ß-catenin signaling pathway.
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Cabelo , Proteínas Wnt , Camundongos , Animais , RNA Interferente Pequeno/genética , Cabelo/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Alopecia/genética , Alopecia/terapia , Alopecia/metabolismo , Via de Sinalização Wnt/fisiologia , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Background: Chronic ocular graft-versus-host disease (oGVHD) is a common ocular complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT), characterized by progressive inflammation of the ocular surface and refractory dry eye. In severe cases, sterile corneal perforation can occur, which poses a significant challenge, due to the low survival rate of grafts after corneal transplantation. Case Presentation: A 47-year-old female presented to our hospital with persistent dryness, foreign body sensation, and blurred vision in her left eye. Diagnosis of graft-versus-host disease with corneal descemetocele in the left eye was made after detailed history review and thorough examination. Multi-layer amniotic membrane transplantation was performed in the affected eye, resulting in amelioration of the patient's symptoms. This amelioration of symptoms provided the patient with a level of comfort that permitted additional time while awaiting corneal transplantation. Conclusions: We report a successful case of multi-layer amniotic membrane transplantation for the management of corneal descemetocele following allo-HSCT.
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Oftalmopatias , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Humanos , Feminino , Pessoa de Meia-Idade , Âmnio/transplante , Doença Enxerto-Hospedeiro/etiologia , CórneaRESUMO
Messenger RNA (mRNA) technology has already been successfully tested preclinically and there are ongoing clinical trials for protein replacement purposes; however, more effort has been put into the development of prevention strategies against infectious diseases. Apparently, mRNA vaccine approval against coronavirus disease 2019 (COVID-19) is a landmark for opening new opportunities for managing diverse health disorders based on this approach. Indeed, apart from infectious diseases, it has also been widely tested in numerous directions including cancer prevention and the treatment of inherited disorders. Interestingly, self-amplifying RNA (saRNA)-based technology is believed to display more developed RNA therapy compared with conventional mRNA technique in terms of its lower dosage requirements, relatively fewer side effects, and possessing long-lasting effects. Nevertheless, some challenges still exist that need to be overcome in order to achieve saRNA-based drug approval in clinics. Hence, the current review discusses the feasibility of saRNA utility for protein replacement therapy on various health disorders including rare hereditary diseases and also provides a detailed overview of saRNA advantages, its molecular structure, mechanism of action, and relevant delivery platforms.
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COVID-19 , RNA , Humanos , RNA/genética , Vacinas Sintéticas , RNA Mensageiro/genética , Vacinas de mRNARESUMO
To explore any relationship between the ABO blood group and the coronavirus disease 2019 (COVID-19) susceptibility, we compared ABO blood group distributions in 2173 COVID-19 patients with local control populations, and found that blood group A was associated with an increased risk of infection, whereas group O was associated with a decreased risk.
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Sistema ABO de Grupos Sanguíneos , COVID-19 , Suscetibilidade a Doenças , Humanos , Estudos Retrospectivos , SARS-CoV-2RESUMO
The Beclin 1-Vps34 complex, known as "mammalian class III PI3K," plays essential roles in membrane-mediated transport processes including autophagy and endosomal trafficking. Beclin 1 acts as a scaffolding molecule for the complex and readily transits from its metastable homodimeric state to interact with key modulators such as Atg14L or UVRAG and form functionally distinct Atg14L/UVRAG-containing Beclin 1-Vps34 subcomplexes. The Beclin 1-Atg14L/UVRAG interaction relies critically on their coiled-coil domains, but the molecular mechanism remains poorly understood. We determined the crystal structure of Beclin 1-UVRAG coiled-coil complex and identified a strengthened interface with both hydrophobic pairings and electrostatically complementary interactions. This structure explains why the Beclin 1-UVRAG interaction is more potent than the metastable Beclin 1 homodimer. Potent Beclin 1-UVRAG interaction is functionally significant because it renders UVRAG more competitive than Atg14L in Beclin 1 binding and is critical for promoting endolysosomal trafficking. UVRAG coiled-coil mutants with weakened Beclin 1 binding do not outcompete Atg14L and fail to promote endolysosomal degradation of the EGF receptor (EGFR). We designed all-hydrocarbon stapled peptides that specifically targeted the C-terminal part of the Beclin 1 coiled-coil domain to interfere with its homodimerization. One such peptide reduced Beclin 1 self-association, promoted Beclin 1-Atg14L/UVRAG interaction, increased autophagic flux, and enhanced EGFR degradation. Our results demonstrate that the targeting Beclin 1 coiled-coil domain with designed peptides to induce the redistribution of Beclin 1 among its self-associated form or Atg14L/UVRAG-containing complexes enhances both autophagy and endolysosomal trafficking.
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Autofagia/fisiologia , Proteína Beclina-1/metabolismo , Endossomos/metabolismo , Lisossomos/metabolismo , Peptídeos/metabolismo , Domínios e Motivos de Interação entre Proteínas/fisiologia , Transporte Proteico/fisiologia , Proteínas Supressoras de Tumor/metabolismo , Células A549 , Sequência de Aminoácidos , Linhagem Celular , Linhagem Celular Tumoral , Endossomos/fisiologia , Receptores ErbB/metabolismo , Células HEK293 , Humanos , Lisossomos/fisiologia , Domínios Proteicos/fisiologiaRESUMO
ß-Lactamases confer resistance to ß-lactam-based antibiotics. There is great interest in understanding their mechanisms to enable the development of ß-lactamase-specific inhibitors. The mechanism of class A ß-lactamases has been studied extensively, revealing Lys-73 and Glu-166 as general bases that assist the catalytic residue Ser-70. However, the specific roles of these two residues within the catalytic cycle remain not fully understood. To help resolve this, we first identified an E166H mutant that is functional but is kinetically slow. We then carried out time-resolved crystallographic study of a full cycle of the catalytic reaction. We obtained structures that represent apo, ES*-acylation, and ES*-deacylation states and analyzed the conformational changes of His-166. The "in" conformation in the apo structure allows His-166 to form a hydrogen bond with Lys-73. The unexpected "flipped-out" conformation of His-166 in the ES*-acylation structure was further examined by molecular dynamics simulations, which suggested deprotonated Lys-73 serving as the general base for acylation. The "revert-in" conformation in the ES*-deacylation structure aligns His-166 toward the water molecule that hydrolyzes the acyl adduct. Finally, when the acyl adduct is fully hydrolyzed, His-166 rotates back to the "in" conformation of the apo-state, restoring the Lys-73/His-166 interaction. Using His-166 as surrogate, our study identifies distinct conformational changes within the active site during catalysis. We suggest that the native Glu-166 executes similar changes in a less constricted way. Taken together, this structural series improves our understanding of ß-lactam hydrolysis in this important class of enzymes.
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Antibacterianos/metabolismo , beta-Lactamases/química , beta-Lactamases/metabolismo , beta-Lactamas/metabolismo , Acilação , Catálise , Domínio Catalítico , Cristalografia por Raios X , Modelos Moleculares , Mutação/genética , Conformação Proteica , beta-Lactamases/genéticaRESUMO
Bacterial ß-lactamases readily inactivate most penicillins and cephalosporins by hydrolyzing and "opening" their signature ß-lactam ring. In contrast, carbapenems resist hydrolysis by many serine-based class A, C, and D ß-lactamases due to their unique stereochemical features. To improve the resistance profile of penicillins, we synthesized a modified penicillin molecule, MPC-1, by "grafting" carbapenem-like stereochemistry onto the penicillin core. Chemical modifications include the trans conformation of hydrogen atoms at C-5 and C-6 instead of cis, and a 6-α hydroxyethyl moiety to replace the original 6-ß aminoacyl group. MPC-1 selectively inhibits class C ß-lactamases, such as P99, by forming a nonhydrolyzable acyl adduct, and its inhibitory potency is â¼2 to 5 times higher than that for clinically used ß-lactamase inhibitors clavulanate and sulbactam. The crystal structure of MPC-1 forming the acyl adduct with P99 reveals a novel binding mode for MPC-1 that resembles carbapenem bound in the active site of class A ß-lactamases. Furthermore, in this novel binding mode, the carboxyl group of MPC-1 blocks the deacylation reaction by occluding the critical catalytic water molecule and renders the acyl adduct nonhydrolyzable. Our results suggest that by incorporating carbapenem-like stereochemistry, the current collection of over 100 penicillins and cephalosporins can be modified into candidate compounds for development of novel ß-lactamase inhibitors.
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Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Penicilinas/síntese química , Penicilinas/farmacologia , Inibidores de beta-Lactamases/síntese química , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/metabolismo , Sítios de Ligação , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Carbapenêmicos/química , Domínio Catalítico , Cefalosporinas/síntese química , Cefalosporinas/química , Cefalosporinas/farmacologia , Ácido Clavulânico/farmacologia , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular , Penicilinas/química , Estereoisomerismo , Sulbenicilina/farmacologia , Inibidores de beta-Lactamases/químicaRESUMO
Most class A ß-lactamases cannot hydrolyze carbapenem antibiotics effectively. The molecular mechanism of this catalytic inefficiency has been attributed to the unique stereochemistry of carbapenems, including their 6-α-hydroxyethyl side chain and the transition between two tautomeric states when bound at the active site. Previous studies have shown that the 6-α-hydroxyethyl side chain of carbapenems can interfere with catalysis by forming hydrogen bonds with the deacylation water molecule to reduce its nucleophilicity. Here our studies of a class A noncarbapenemase PenP demonstrate that substituting the general base residue Glu166 with Ser or other residues leads to a significant enhancement of the acylation kinetics by â¼100-500 times toward carbapenems like meropenem. The structures of PenP and Glu166Ser both in apo form and in complex with meropenem reveal that Glu166 is critical for the formation of a hydrogen bonding network within the active site that locks Asn170 in an orientation to impose steric clash with the 6-α-hydroxyethyl side chain of meropenem. The Glu166Ser substitution weakens this network and enables Asn170 to adopt an alternative conformation to avoid steric clash and accommodate faster acylation kinetics. Furthermore, the weakened hydrogen bonding network caused by the Glu166Ser substitution allows the 6-α-hydroxyethyl moiety to adopt a catalytically favorable orientation as seen in class A carbapenemases. In summary, our data identify a previously unreported role of the universally conserved general base residue Glu166 in impeding the proper binding of carbapenems by restricting their 6-α-hydroxyethyl group.
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Carbapenêmicos/metabolismo , beta-Lactamases/química , beta-Lactamases/metabolismo , Acilação , Substituição de Aminoácidos , Bacillus/enzimologia , Sítios de Ligação , Domínio Catalítico , Cefaloridina/química , Cristalografia por Raios X , Ácido Glutâmico/química , Cinética , Meropeném , Modelos Moleculares , Conformação Proteica , Tienamicinas/metabolismo , beta-Lactamases/genéticaRESUMO
Despite the availability of prevention and treatment strategies and advancing immunization approaches, the influenza virus remains a global threat that continues to plague humanity with unpredictable pandemics. Due to the unusual genetic variability and segmented genome, the reassortment between different strains of influenza is facilitated and the viruses continuously evolve and adapt to the host cell's immunity. This underlies the seasonal vaccine mismatches that decrease the vaccine efficacy and increase the risk of outbreaks. Thus, the development of a universal vaccine covering all the influenza A and B strains would reduce the pervasiveness of the influenza virus. In the current study, a potentially universal influenza multi-epitope vaccine was designed based on the experimentally tested conserved T cell and B cell epitopes of hemagglutinin (HA), neuraminidase (NA), nucleoprotein (NP), and matrix-2 proton channel (M2) of the virus. The immune simulation and molecular docking of the vaccine construct with TLR2, TLR3, and TLR4 elicited the favorable immunogenicity of the vaccine and the formation of stable complexes, respectively. Ultimately, based on the immunoinformatics analysis, the universal mRNA multi-epitope vaccine designed in this study might have a protection potential against the various subtypes of influenza A and B.
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Vacinas contra Influenza , Influenza Humana , Orthomyxoviridae , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Epitopos/genética , Pandemias/prevenção & controle , Simulação de Acoplamento Molecular , Anticorpos AntiviraisRESUMO
The spike protein of SARS-CoV-2 has been widely used as an effective vaccine immunogen, although some limitations still remain. Herein, O-GalNAc glycosylated RBD (Tn-RBD) was synthesized as an antigen via in vitro glycosylation reactions. The inhibition ability against hACE2 binding of antibodies induced with Tn-RBD was 30-40% increased compared to that induced with RBD. This result implies that Tn-glycosylation might play important roles in the immunogenicity of the RBD protein, which should be considered in the design of novel vaccines to fight against COVID-19.
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COVID-19 , Vacinas Virais , Humanos , Glicoproteína da Espícula de Coronavírus/química , SARS-CoV-2 , Anticorpos Antivirais , GlicosilaçãoRESUMO
Skin wounds are a major medical challenge that threaten human health. Functional hydrogel dressings demonstrate great potential to promote wound healing. In this study, magnesium (Mg) and zinc (Zn) are introduced into methacrylate gelatin (GelMA) hydrogel via low-temperature magnetic stirring and photocuring, and their effects on skin wounds and the underlying mechanisms are investigated. Degradation testing confirmed that the GelMA/Mg/Zn hydrogel released magnesium ions (Mg2+) and zinc ions (Zn2+) in a sustained manner. The Mg2+ and Zn2+ not only enhanced the migration of human skin fibroblasts (HSFs) and human immortalized keratinocytes (HaCats), but also promoted the transformation of HSFs into myofibroblasts and accelerated the production and remodeling of extracellular matrix. Moreover, the GelMA/Mg/Zn hydrogel enhanced the healing of full-thickness skin defects in rats via accelerated collagen deposition, angiogenesis and skin wound re-epithelialization. We also identified the mechanisms through which GelMA/Mg/Zn hydrogel promoted wound healing: the Mg2+ promoted Zn2+ entry into HSFs and increased the concentration of Zn2+ in HSFs, which effectively induced HSFs to differentiate into myofibroblasts by activating the STAT3 signaling pathway. The synergistic effect of Mg2+ and Zn2+ promoted wound healing. In conclusion, our study provides a promising strategy for skin wounds regeneration.
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Monkeypox (mpox) is a zoonotic infectious disease caused by the mpox virus. Mpox symptoms are similar to smallpox with less severity and lower mortality. As yet mpox virus is not characterized by as high transmissibility as some severe acute respiratory syndrome 2 (SARS-CoV-2) variants, still, it is spreading, especially among men who have sex with men (MSM). Thus, taking preventive measures, such as vaccination, is highly recommended. While the smallpox vaccine has demonstrated considerable efficacy against the mpox virus due to the antigenic similarities, the development of a universal anti-mpox vaccine remains a necessary pursuit. Recently, nucleic acid vaccines have garnered special attention owing to their numerous advantages compared to traditional vaccines. Importantly, DNA vaccines have certain advantages over mRNA vaccines. In this study, a potentially universal DNA vaccine candidate against mpox based on conserved epitopes was designed and its efficacy was evaluated via an immunoinformatics approach. The vaccine candidate demonstrated potent humoral and cellular immune responses in silico, indicating the potential efficacy in vivo and the need for further research.
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Titanium (Ti) and Ti alloys are commonly used in dental implants, which have good biocompatibility, mechanical strength, processability, and corrosion resistance. However, the surface inertia of Ti implants leads to delayed integration of Ti and new bone, as well as problems such as aseptic loosening and inadequate osseointegration. Magnesium (Mg) ions can promote bone regeneration, and many studies have used Mg-containing materials to modify the Ti implant surface. This systematic review summarizes the methods, effects, and clinical applications of surface modification of Ti implants with Mg-containing coatings. Database collection was completed on Janury 1, 2023, and a total of 29 relevant studies were ultimately included. Mg can be compounded with different materials and coated to the surface of Ti implants using different methods. In vitro and in vivo experiments have shown that Mg-containing coatings promote cell adhesion and osteogenic differentiation. On the one hand, the surface roughness of implants increases with the addition of Mg-containing coatings, which is thought to have an impact on the osseointegration of the implant. On the other hand, Mg ions promote cell attachment through binding interactions between the integrin family and FAK-related signaling pathways. And Mg ions could induce osseointegration by activating PI3K, Notch, ERK/c-Fos, BMP-4-related signaling pathways and TRPM7 protein channels. Overall, Mg-based coatings show great potential for the surface modification of Ti implants to promote osseointegration. STATEMENT OF SIGNIFICANCE: The inertia surface of titanium (Ti) implants leads to delayed osseointegration. Magnesium (Mg) ions, known for promoting bone regeneration, have been extensively studied to modify the surface of Ti implants. However, no consensus has been reached on the appropriate processing methods, surface roughness and effective concentration of Mg-containing coatings for osseointegration. This systematic review focus on the surface modification of Ti implants with Mg-containing compounds, highlighting the effects of Mg-containing coatings on the surface properties of Ti implants and its associated mechanisms. Besides, we also provide an outlook on future directions to promote the clinical application of Mg-modified implants.
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Osseointegração , Osteogênese , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Íons/farmacologia , Magnésio/farmacologia , Propriedades de Superfície , Titânio/farmacologia , Titânio/químicaRESUMO
Notwithstanding the presence of a smallpox vaccine that is effective against monkeypox (mpox), developing a universal vaccine candidate against monkeypox virus (MPXV) is highly required as the mpox multi-country outbreak has increased global concern. MPXV, along with variola virus (VARV) and vaccinia virus (VACV), belongs to the Orthopoxvirus genus. Due to the genetic similarity of antigens in this study, we have designed a potentially universal mRNA vaccine based on conserved epitopes that are specific to these three viruses. In order to design a potentially universal mRNA vaccine, antigens A29, A30, A35, B6, and M1 were selected. The conserved sequences among the three viral species-MPXV, VACV, and VARV-were detected, and B and T cell epitopes containing the conserved elements were used for the design of the multi-epitope mRNA construct. Immunoinformatics analyses demonstrated the stability of the vaccine construct and optimal binding to MHC molecules. Humoral and cellular immune responses were induced by immune simulation analyses. Eventually, based on in silico analysis, the universal mRNA multi-epitope vaccine candidate designed in this study may have a potential protection against MPXV, VARV, and VACV that will contribute to the advancement of prevention strategies for unpredictable pandemics.
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Mpox , Vacina Antivariólica , Varíola , Vírus da Varíola , Humanos , Vaccinia virus/genética , Vírus da Varíola/genética , Varíola/prevenção & controle , Epitopos/metabolismo , Vacina Antivariólica/genética , Monkeypox virus/genética , Vacinas de mRNARESUMO
Pseudomonas aeruginosa (PA) is a leading cause of hospital-acquired and ventilator-associated pneumonia. The multidrug-resistance (MDR) rate of PA is increasing making the management of PA a global challenge. Messenger RNA (mRNA) vaccines represent the most promising alternative to conventional vaccines and are widely studied for viral infection and cancer immunotherapy while rarely studied for bacterial infections. In this study, two mRNA vaccines encoding PcrV- the key component of the type III secretion system in Pseudomonas and the fusion protein OprF-I comprising outer membrane proteins OprF and OprI were constructed. The mice were immunized with either one of these mRNA vaccines or with the combination of both. Additionally, mice were vaccinated with PcrV, OprF, or the combination of these two proteins. Immunization with either mRNA-PcrV or mRNA-OprF-I elicited a Th1/Th2 mixed or slighted Th1-biased immune response, conferred broad protection, and reduced bacterial burden and inflammation in burn and systemic infection models. mRNA-PcrV induced significantly stronger antigen-specific humoral and cellular immune responses and higher survival rate compared with the OprF-I after challenging with all the PA strains tested. The combined mRNA vaccine demonstrated the best survival rate. Moreover, the mRNA vaccines showed the superiority over protein vaccines. These results suggest that mRNA-PcrV as well as the mixture of mRNA-PcrV and mRNA-OprF-I are promising vaccine candidates for the prevention of PA infection.
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Since the first outbreak in the 19th century influenza virus has remained emergent owing to the huge pandemic potential. Only the pandemic of 1918 caused more deaths than any war in world history. Although two types of influenza- A (IAV) and B (IBV) cause epidemics annually, influenza A deserves more attention as its nature is much wilier. IAVs have a large animal reservoir and cause the infection manifestation not only in the human population but in poultry and domestic pigs as well. This many-sided characteristic of IAV along with the segmented genome gives rise to the antigenic drift and shift that allows evolving the new strains and new subtypes, respectively. As a result, the immune system of the body is unable to recognize them. Importantly, several highly pathogenic avian IAVs have already caused sporadic human infections with a high fatality rate (~60%). The current review discusses the promising strategy of using a potentially universal IAV mRNA vaccine based on conserved elements for humans, poultry, and pigs. This will better aid in averting the outbreaks in different susceptible species, thus, reduce the adverse impact on agriculture, and economics, and ultimately, prevent deadly pandemics in the human population.
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Vacinas contra Influenza , Influenza Humana , Humanos , Animais , Suínos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Aves Domésticas , RNA Mensageiro , Vacinas de mRNARESUMO
Until May 2022, zoonotic infectious disease monkeypox (MPX) caused by the monkeypox virus (MPXV) was one of the forgotten viruses considered to be geographically limited in African countries even though few cases outside of Africa were identified. Central and West African countries are known to be endemic for MPXV. However, since the number of human MPX cases has rapidly increased outside of Africa the global interest in this virus has markedly grown. The majority of infected people with MPXV have never been vaccinated against smallpox virus. Noteworthily, the MPXV spreads fast in men who have sex with men (MSM). Preventive measures against MPXV are essential to be taken, indeed, vaccination is the key. Due to the antigenic similarities, the smallpox vaccine is efficient against MPXV. Nevertheless, there is no specific MPXV vaccine until now. Nucleic acid vaccines deserve special attention since the emergency approval of two messenger RNA (mRNA)-based coronavirus disease 2019 (COVID-19) vaccines in 2020. This milestone in vaccinology has opened a new platform for developing more mRNA- or DNA-based vaccines. Certainly, this type of vaccine has a number of advantages including time- and cost-effectiveness over conventional vaccines. The platform of nucleic acid-based vaccines gives humankind a huge opportunity. Ultimately, there is a strong need for developing a universal vaccine against MPXV. This review will shed the light on the strategies for developing nucleic acid vaccines against MPXV in a timely manner. Consequently, developing nucleic acid-based vaccines may alleviate the global threat against MPXV.
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COVID-19 , Mpox , Minorias Sexuais e de Gênero , Vacina Antivariólica , Masculino , Humanos , Mpox/prevenção & controle , Homossexualidade Masculina , Vacinas Baseadas em Ácido Nucleico , COVID-19/prevenção & controle , Monkeypox virus/genética , RNA MensageiroRESUMO
Harnessing highly conserved peptides derived from the receptor binding domain (RBD) of spike (S) protein to construct peptide-based inhibitors is one of the most effective strategies to fight against the ever-mutating coronavirus SARS-CoV-2. But how the O-glycosylation affects their inhibition abilities has not been intensively explored. Herein, an intrinsic O-glycosylated peptide P320-334 derived from RBD was screened and homogeneous O-linked glycopeptides containing Tn (GalNAcα1-O-Ser/Thr), T (Galß1-3GalNAcα1-O-Ser/Thr), sialyl-Tn (sTn, Siaα2-6GalNAcα1-O-Ser/Thr), and sialyl-T (sT, Siaα2-3Galß1-3GalNAcα1-O-Ser/Thr) structures were first synthesized via chemoenzymatic strategies. Compared with the unglycosylated peptide, the binding of sT-P320-334 to hACE2 was enhanced to 133% and the inhibition capacity against RBD-hACE2 binding of sTn- and sT-P320-334 was significantly increased up to 150-410%. Thus, our results suggest the sialic acid residue on the terminal of short O-glycan structures might strengthen the inhibition capacities of these peptide-based inhibitors, which might provide novel optimization directions for the inhibitor design.
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COVID-19 , Glicopeptídeos , Glicopeptídeos/química , Glicopeptídeos/farmacologia , Humanos , Ácido N-Acetilneuramínico , Peptídeos , Polissacarídeos , SARS-CoV-2RESUMO
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is undoubtedly the most challenging pandemic in the current century and remains a global health emergency. As the number of COVID-19 cases in the world is on the rise and variants continue to emerge, there is an urgent need for vaccines. Among all immunization approaches, mRNA vaccines have demonstrated more promising results in response to this challenge. Herein, we designed an mRNA-based vaccine encoding the receptor-binding domain (RBD) of SARS-CoV-2 encapsulated in lipid nanoparticles (LNPs). Intramuscular (i.m.) administration of the mRNA-RBD vaccine elicited broad-spectrum neutralizing antibodies and cellular responses against not only the wild-type SARS-CoV-2 virus but also Delta and Omicron variants. These results indicated that two doses of mRNA-RBD immunization conferred a strong immune response in mice against the wild-type SARS-CoV-2, while the booster dose provided a sufficient immunity against SARS-CoV-2 and its variants. Taken together, the three-dose regimen strategy of the mRNA-RBD vaccine proposed in the present study appears to be a promising reference for the development of mRNA vaccines targeting SARS-CoV-2 variants.
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Despite the existence of various types of vaccines and the involvement of the world's leading pharmaceutical companies, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains the most challenging health threat in this century. Along with the increased transmissibility, new strains continue to emerge leading to the need for more vaccines that would elicit protectiveness and safety against the new strains of the virus. Nucleic acid vaccines seem to be the most effective approach in case of a sudden outbreak of infection or the emergence of a new strain as it requires less time than any conventional vaccine development. Hence, in the current study, a DNA vaccine encoding the trimeric prefusion-stabilized ectodomain (S1+S2) of SARS-CoV-2 S-protein was designed by introducing six additional prolines mutation, termed HexaPro. The three-dose regimen of designed DNA vaccine immunization in mice demonstrated the generation of protective antibodies.