Publications by authors named "Guillermo Posadas-Herrera"

Introduction: Duchenne muscular dystrophy (DMD) is a genetic disorder caused by mutations in the dystrophin-encoding gene that leads to muscle necrosis and degeneration with chronic inflammation during growth, resulting in progressive generalized weakness of the skeletal and cardiac muscles. We previously demonstrated the therapeutic effects of systemic administration of dental pulp mesenchymal stromal cells (DPSCs) in a DMD animal model. We showed preservation of long-term muscle function and slowing of disease progression.

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Rabies virus (RABV) causes fatal neurological disease. Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) using inactivated-virus vaccines are the most effective measures to prevent rabies. In Japan, HEP-Flury, the viral strain, used as a human rabies vaccine, has historically been propagated in primary fibroblast cells derived from chicken embryos.

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Rabies is a fatal encephalitic infectious disease caused by the rabies virus (RABV). RABV is highly neurotropic and replicates in neuronal cell lines . The RABV fixed strain, HEP-Flury, was produced via passaging in primary chicken embryonic fibroblast cells.

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Adeno-associated virus (AAV) vector-based gene therapy is potentially curative for various genetic diseases; however, the development of a scalable purification method for full-genome AAV vectors remains crucial to increase productivity and reduce cost of GMP production. In this study, we developed a large-scale short-term purification method for functional full-genome AAV particles by using 2-step cesium chloride (CsCl) density-gradient ultracentrifugation with a zonal rotor. The 2-step CsCl method with a zonal rotor improves separation between empty and full-genome AAV particles, reducing the ultracentrifugation time (4-5 h) and increasing the AAV volume for purification.

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The rabies virus is widely distributed and vaccines are an important strategy to prevent its spread. The whole-genome sequences of rabies strains in relation to vaccine development provide essential information to maintain vaccine quality and develop new vaccines. However, the genetic characteristics of the purified chick embryo cell culture rabies vaccine, KM Biologics (PCECV-KMB), developed in Japan in the 1970s, have not been explored.

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Article Synopsis
  • Musculocontractural Ehlers-Danlos syndrome (mcEDS) is a condition caused by problems in a gene that helps produce a substance important for skin and muscle health.
  • Researchers created special mice with changes to this gene using a tool called CRISPR/Cas9, which allowed them to study how this condition affects the body without the mice dying too early.
  • The mutant mice showed issues like weak muscles, growth problems, and fragile skin, which help scientists understand the effects of mcEDS better and work on potential treatments.
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  • The gene encodes an enzyme essential for producing dermatan sulfate, which is important for connective tissue integrity, and its deficiency is linked to musculocontractural Ehlers-Danlos syndrome (mcEDS), resulting in tissue fragility and malformations.
  • Research using a mouse model showed myopathy traits related to the absence of this enzyme, indicating that decorin, a molecule crucial for muscle health, is mislocalized and functions abnormally in these deficient mice.
  • Findings revealed imbalances in muscle-related proteins and increased fibrosis in the deficient mice, suggesting that the lack of dermatan sulfate disrupts normal muscle development and function.
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Background: Duchenne muscular dystrophy (DMD) is an inherited progressive disorder that causes skeletal and cardiac muscle deterioration with chronic inflammation. Dental pulp stem cells (DPSCs) are attractive candidates for cell-based strategies for DMD because of their immunosuppressive properties. Therefore, we hypothesized that systemic treatment with DPSCs might show therapeutic benefits as an anti-inflammatory therapy.

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Duchenne muscular dystrophy (DMD) is a severe congenital disease associated with mutation of the dystrophin gene. Supplementation of dystrophin using recombinant adeno-associated virus (rAAV) has promise as a treatment for DMD, although vector-related general toxicities, such as liver injury, neurotoxicity, and germline transmission, have been suggested in association with the systemic delivery of high doses of rAAV. Here, we treated normal or dystrophic dogs with rAAV9 transduction in conjunction with multipotent mesenchymal stromal cell (MSC) injection to investigate the therapeutic effects of an rAAV expressing microdystrophin (μDys) under conditions of immune modulation.

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  • MERS-CoV is a dangerous emerging virus with no approved vaccines or treatments, prompting the development of a new bivalent vaccine.
  • The novel vaccine, named RVΔP-MERS/S1, is built using a modified rabies virus that expresses a key MERS-CoV protein (S1), aimed at producing immune responses.
  • Experiments showed that mice vaccinated with RVΔP-MERS/S1 developed neutralizing antibodies against both MERS-CoV and rabies virus without showing signs of rabies, suggesting it could be a safe and effective vaccine.
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Background: Lymphocytic choriomeningitis virus (LCMV) causes a variety of diseases, including asymptomatic infections, meningitis, and congenital infections in the fetus of infected mother. The development of a safe and effective vaccine against LCMV is imperative. This study aims to develop a new candidate vaccine against LCMV using a recombinant replication-incompetent rabies virus (RV) vector.

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  • The Thogotovirus genus includes tick-borne viruses like Thogoto and Dhori viruses, and a new virus called Oz virus (OZV) has been isolated from ticks in Japan.
  • OZV has shown efficient replication in various cell types and can cause high mortality in young mice when introduced to the brain.
  • Genetic analysis reveals that OZV is closely related to the Bourbon virus, highlighting the importance of studying its ecology and potential health risks.
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In Japan, indigenous tick-borne phleboviruses (TBPVs) and their associated diseases first became evident in 2013 by reported human cases of severe fever with thrombocytopenia syndrome (SFTS). In this study, we report a novel member of the genus Phlebovirus designated as Kabuto Mountain virus (KAMV), which was isolated from the ixodid tick Haemaphysalis flava in Hyogo, Japan. A complete viral genome sequencing and phylogenetic analyses showed that KAMV is a novel member of TBPVs, which is closely related to the Uukuniemi and Kaisodi group viruses.

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  • - Three similar isolates of a novel virus, named Tarumizu tick virus (TarTV), were discovered from hard ticks in Japan, showing they are closely related yet distinct strains.
  • - TarTV has a genome consisting of 12 double-stranded RNA segments, with 10 segments exhibiting similarities to proteins of other known tick-borne viruses, indicating it may belong to the Coltivirus genus.
  • - Electron microscopy revealed TarTV has a non-enveloped icosahedral structure, and while it can replicate in mammalian cells, it does not cause symptoms in infected mice, highlighting its potential for further study on genetic diversity within the Coltivirus family.
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Potency controls of inactivated rabies vaccines for human use are confirmed by the National Institutes of Health challenge test in which lethal infection with severe neurological symptoms should be observed in approximately half of the mice inoculated with the rabies virus. Weight loss, decreased body temperature, and the presence of rabies-associated neurological signs have been proposed as humane endpoints. The potential for reduction of animal suffering by introducing humane endpoints in the potency test for inactivated rabies vaccine for human use was investigated.

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Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease in East Asia. It is thought that the SFTS virus (SFTSV) circulates between ticks and animals in nature and that the virus is transmitted to humans by tick bites. SFTS is endemic to Nagasaki in western Japan; however, epidemiological information regarding SFTSV in Nagasaki is not known.

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Yellow fever (YF) is an acute hemorrhagic viral infection transmitted by mosquitoes in Africa and South America. The major challenge in YF disease detection and confirmation of outbreaks in Africa is the limited availability of reference laboratories and the persistent lack of access to diagnostic tests. We used wild-type YF virus sequences to generate recombinant envelope protein in an Escherichia coli expression system.

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Ixodid ticks transmit several important viral pathogens. We isolated a new virus (Tofla virus: TFLV) from Heamaphysalis flava and Heamaphysalis formsensis in Japan. The full-genome sequences revealed that TFLV belonged to the genus Nairovirus, family Bunyaviridae.

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Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral disease that is endemic in China, Korea and Japan. No effective vaccine or specific treatment for SFTS is currently available. Here, we used a mouse model to examine the effects of ribavirin, site-1 protease inhibitor PF-429242, steroids, and combination of minocycline and ciprofloxacin (MC) on SFTS infection.

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In 2005, we isolated a new species of virus from mosquitoes in the Philippines. The virion was elliptical in shape and had a short single projection. The virus was named Tanay virus (TANAV) after the locality in which it was found.

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A formalin-inactivated West Nile Virus (WNV) vaccine (WN-VAX) derived from the WNV-NY99 strain was tested for its safety, efficacy, dilution limit for complete protection, and cross-neutralization. Safety tests performed with experimental animals, bacteria, or cultured cell lines showed no evidence of short- or long-term adverse effects. WN-VAX also protected 100% of 4-week-old mice against a lethal challenge from the WNV-NY99 strain after two doses of intraperitoneal inoculation-even when the vaccine was diluted to 3.

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