19 research outputs found

    Traumatic Brain Injury Stimulates Neural Stem Cell Proliferation via Mammalian Target of Rapamycin Signaling Pathway Activation

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    Neural stem cells in the adult brain possess the ability to remain quiescent until needed in tissue homeostasis or repair. It was previously shown that traumatic brain injury (TBI) stimulated neural stem cell (NSC) proliferation in the adult hippocampus, indicating an innate repair mechanism, but it is unknown how TBI promotes NSC proliferation. In the present study, we observed dramatic activation of mammalian target of rapamycin complex 1 (mTORC1) in the hippocampus of mice with TBI from controlled cortical impact (CCI). The peak of mTORC1 activation in the hippocampal subgranular zone, where NSCs reside, is 24-48 h after trauma, correlating with the peak of TBI-enhanced NSC proliferation. By use of a Nestin-GFP transgenic mouse, in which GFP is ectopically expressed in the NSCs, we found that TBI activated mTORC1 in NSCs. With 5-bromo-2'-deoxyuridine labeling, we observed that TBI increased mTORC1 activation in proliferating NSCs. Furthermore, administration of rapamycin abolished TBI-promoted NSC proliferation. Taken together, these data indicate that mTORC1 activation is required for NSC proliferation postinjury, and thus might serve as a therapeutic target for interventions to augment neurogenesis for brain repair after TBI

    mTOR SIGNALING MEDIATES TBI-ENHANCED NEURAL STEM CELL PROLIFERAION

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    poster abstractTraumatic Brain Injury (TBI) induced neuron death was once thought to be irreversible. However, the identification of neural stem cells (NSCs) in the adult brain holds the hope of repairing injured brain following TBI. Our pre-vious study showed that TBI promotes NSC proliferation in an attempt to ini-tial an innate repair and/or plasticity mechanisms. However, this induced proliferation is transient without significantly increasing neurogenesis. It suggests that additional intervention is required to further increase NSC pro-liferation to enhance neurogenesis for successfully repairing the damaged brain following TBI. In order to determine the molecular mechanism that mediates TBI-enhanced NSC proliferation, we assessed the activity of mam-malian target of rapamycin (mTOR) signaling by detecting the level of Phospho-S6 Ribosomal protein (pS6), an indicator of the activity of mTOR signaling. We found that the level of pS6 was transient but dramatically in-creased prior to TBI-enhanced NSC proliferation. In contrast inhibiting the activity of mTOR signaling with rapamycin attenuated this effect, indicating that mTOR signaling mediates TBI-enhanced NSC proliferation. Further stimulating mTOR signaling strengthened the effect of TBI-enhanced NSC proliferation. These results suggest that mTOR signaling mediates TBI-enhanced neural stem cell proliferation and stimulating mTOR signaling may be a potential therapeutic approach to enhance neurogenesis for post-traumatic functional recovery

    Barriers and facilitators of HIV vaccine and prevention study participation among Young Black MSM and transwomen in New York City

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    <div><p>Background</p><p>Black men who have sex with men (MSM), and Transwomen (TW) shoulder disproportionate burden of HIV. However, they are unrepresented in HIV vaccine trials. We investigated the perceptions of that factors associated with HIV vaccine trials participation among Black MSM and TW in New York.</p><p>Methods</p><p>Self-administered online questionnaires were administered to 18–29 years of NYC residents who identified as Black MSM and TW, assessing demographics, awareness and willingness to participate in HIV vaccine trials, barriers and facilitators associated with willingness, and sexual behaviors. Frequency summation was performed to determine barriers and facilitators, and logistic regression analysis was performed to determine factors association with expressed willingness.</p><p>Results</p><p>Black MSM and TW who reported engaging in risk behaviors had a 61% lower likelihood of participating in HIV vaccine trials when compared to those who did not report engaging in any risk behavior. Facilitators associated with trial participation were: cash compensation, confidentiality regarding participation, public transportation vouchers, gift cards, and food or grocery vouchers as potential facilitators for trial participation. Conversely, fear of side effects from the vaccine, concerns about testing positive on routine HIV testing due to an HIV vaccine, limited knowledge of research trials, and fear of being judged as HIV-positive were perceived as barriers.</p><p>Conclusions</p><p>These findings provided insights into the considerations and perceptions of Black MSM and TW towards HIV vaccine trials. However, further studies are needed to delineate the complex mechanisms underlying the decision-making process and establish approaches to increase study participation in this population.</p></div

    Sexual patterns and practices among men who have sex with men and transgender women in Thailand: A qualitative assessment.

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    The global trend in HIV incidence overall is declining; however, there is a plateau in new HIV infection among men who have sex with men (MSM) and transgender women (TGW) despite extensive investment in HIV prevention targeting these populations. Many studies usually conflate these two groups together, which may overlook many disparate characteristics unique to each population, impeding the efficacy of HIV interventions. To better understand the vulnerable diversity that may put these individuals at risk of HIV infection, we conducted qualitative analysis among Thai MSM and TGW, aiming to identify sexual pattern themes of MSM and TGW in Bangkok in order to better understand their distinctive sexual life context. Convenient and purposive samplings were used to recruit Thai MSM and TGW aged ≥ 18 years old and living in Bangkok, Thailand, for focused group discussions and one-on-one in-depth interviews, respectively. Total of 12 MSM and 13 TGW participated in focused group discussions, which were conducted separately for MSM and TGW. Additionally, 5 MSM and 5 TGW were involved in one-on-one in-depth interviews. Thematic analyses were performed separately for MSM and TGW. The results show that MSM and TGW have distinct and diverse sexual patterns, and within the identified themes: partnering, partner finding, protection, and enhancing sexual pleasure (only for MSM). Participants reported having varying sexual experiences. Recognizing the difference and diversity in partnering and sexual practice of MSM and TGW is crucial in order to develop tailored interventions that suit the vulnerability of the key populations in Thailand

    Factors associated with Willingness to participate in HIV vaccine trials among those who have not participated in HIV vaccine trials in the past (N = 189) and multivariable logistic regression examining the association between willingness to participate in HIV vaccine trials and sociodemographic characteristics and risk score (N = 155).

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    <p>Factors associated with Willingness to participate in HIV vaccine trials among those who have not participated in HIV vaccine trials in the past (N = 189) and multivariable logistic regression examining the association between willingness to participate in HIV vaccine trials and sociodemographic characteristics and risk score (N = 155).</p
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