Toll gates: An emerging therapeutic target

Combination antiretroviral therapy (cART) restores HIV-1 infection-mediated impairment of JAK-STAT signaling pathway

JAK-STAT signaling pathway has a crucial role in host innate immunity against viral infections, including HIV-1. We therefore examined the impact of HIV-1 infection and combination antiretroviral therapy (cART) on JAK-STAT signaling pathway. Compared to age-matched healthy donors (n = 18), HIV-1-infected subjects (n = 18) prior to cART had significantly lower expression of toll-like receptors (TLR-1/4/6/7/8/9), the IFN regulatory factors (IRF-3/7/9), and the antiviral factors (OAS-1, MxA, A3G, PKR, and Tetherin). Three months’ cART partially restores the impaired functions of JAK-STAT-mediated antiviral immunity. We also found most factors had significantly positive correlations (p < 0.05) between each two factors in JAK-STAT pathway in healthy donors (98.25%, 168/171), but such significant positive associations were only found in small part of HIV-1-infected subjects (43.86%, 75/171), and stably increased during the cART (57.31%, 98/171 after 6 months’ cART). With regard to the restoration of some HIV-1 restriction factors, HIV-1-infected subjects who had CD4+ T cell counts > 350//μl responded better to cART than those with the counts < 350/μl. These findings indicate that the impairment of JAK-STAT pathway may play a role in the immunopathogenesis of HIV-1 disease.

Biomarkers of Resilience in Stress Reduction for Caregivers of Alzheimer's Patients

Caregiving for a dementia patient is associated with increased risk of psychological and physical health problems. We investigated whether a mindfulness-based stress reduction (MBSR) training course for caregivers that closely models the MBSR curriculum originally established by the Center of Mindfulness at the University of Massachusetts may improve the psychological resilience of non-professional caregivers of Alzheimer's disease patients. Twenty adult non-professional caregivers of dementia patients participated in an 8-week MBSR training course. Caregiver stress, depression, burden, grief, and gene expression profiles of blood mononuclear cells were assessed at baseline and following MBSR. MBSR training significantly improved the psychological resilience of some of the caregivers. We identified predictive biomarkers whose expression is associated with the likelihood of caregivers to benefit from MBSR, and biomarkers whose expression is associated with MBSR psychological benefits. Our biomarker studies provide insight into the mechanisms of health benefits of MBSR and a basis for developing a personalized medicine approach for applying MBSR for promoting psychological and cognitive resilience in caregivers of dementia patients.

The Alpha-Melanocyte-Stimulating Hormone Suppresses TLR2-Mediated Functional Responses through IRAK-M in Normal Human Keratinocytes

Alpha-melanocyte stimulating hormone (α-MSH) is a highly conserved 13-aa neuropeptide derived from pro-opiomelanocortin by post-translational processing, which has been reported to exhibit potent anti-inflammatory activity and a wide range of immunosuppressive activities in the skin. However, the regulatory effect of α-MSH is not completely clear in cutaneous innate immunity. In this study, we investigate the functional regulation of α-MSH in TLR2-mediated inflammatory responses in normal human keratinocytes (HKs). α-MSH pretreatment down-regulated the Staphylococcus aureus LTA-induced expression of both TLR2 and IL-8 as well as NF-κB nuclear translocation in HK cells. The inhibitory effect of α-MSH was blocked by agouti signaling protein (ASP), an α-MSH receptor-1 antagonist. To investigate the mechanism of this response in more detail, siRNA of IRAK-M, a negative regulator of TLR signaling, was utilized in these studies. The α-MSH suppressive effect on IL-8 production and NF-κB transactivation was inhibited by IRAK-M siRNA transfection in HK cells. These results indicate that α-MSH is capable of suppressing keratinocyte TLR2-mediated inflammatory responses induced by S. aureus-LTA, thus demonstrating another novel immunomodulatory activity of α-MSH in normal human keratinocytes.