• Role of adenylyl cyclase 6 in the development of lithium-induced nephrogenic diabetes insipidus

      Poulsen, Søren Brandt; Kristensen, Tina Bøgelund; Brooks, Heddwen L.; Kohan, Donald E.; Rieg, Timo; Fenton, Robert A.; Univ Arizona, Coll Med, Dept Physiol (AMER SOC CLINICAL INVESTIGATION INC, 2017-04-06)
      Psychiatric patients treated with lithium (Li+) may develop nephrogenic diabetes insipidus (NDI). Although the etiology of Li+-induced NDI (Li-NDI) is poorly understood, it occurs partially due to reduced aquaporin-2 (AQP2) expression in the kidney collecting ducts. A mechanism postulated for this is that Li+ inhibits adenylyl cyclase (AC) activity, leading to decreased cAMP, reduced AQP2 abundance, and less membrane targeting. We hypothesized that Li-NDI would not develop in mice lacking AC6. Whole-body AC6 knockout (AC6(-/-)) mice and potentially novel connecting tubule/principal cell-specific AC6 knockout (AC6(loxloxCre)) mice had approximately 50% lower urine osmolality and doubled water intake under baseline conditions compared with controls. Dietary Li+ administration increased water intake and reduced urine osmolality in control, AC6(-/)-, and AC6(loxloxCre) mice. Consistent with AC6(-/-) mice, medullary AQP2 and pS256-AQP2 abundances were lower in AC6(loxloxCre) mice compared with controls under standard conditions, and levels were further reduced after Li+ administration. AC6loxloxCre and control mice had a similar increase in the numbers of proliferating cell nuclear antigen-positive cells in response to Li+. However, AC6(loxloxCre) mice had a higher number of H+-ATPase B1 subunit-positive cells under standard conditions and after Li+ administration. Collectively, AC6 has a minor role in Li-NDI development but may be important for determining the intercalated cell-to-principal cell ratio.
    • Tissue-resident macrophages can contain replication-competent virus in antiretroviral-naive, SIV-infected Asian macaques

      DiNapoli, Sarah R.; Ortiz, Alexandra M.; Wu, Fan; Matsuda, Kenta; Twigg, Homer L.; Hirsch, Vanessa M.; Knox, Kenneth; Brenchley, Jason M.; Univ Arizona, Dept Med (AMER SOC CLINICAL INVESTIGATION INC, 2017-02-23)
      SIV DNA can be detected in lymphoid tissue-resident macrophages of chronically SIV-infected Asian macaques. These macrophages also contain evidence of recently phagocytosed SIV-infected CD4(+) T cells. Here, we examine whether these macrophages contain replication-competent virus, whether viral DNA can be detected in tissue-resident macrophages from antiretroviral (ARV) therapy-treated animals and humans, and how the viral sequences amplified from macrophages and contemporaneous CD4(+) T cells compare. In ARV-naive animals, we find that lymphoid tissue-resident macrophages contain replication-competent virus if they also contain viral DNA in ARV-naive Asian macaques. The genetic sequence of the virus within these macrophages is similar to those within CD4(+) T cells from the same anatomic sites. In ARV-treated animals, we find that viral DNA can be amplified from lymphoid tissue-resident macrophages of SIV-infected Asian macaques that were treated with ARVs for at least 5 months, but we could not detect replicationcompetent virus from macrophages of animals treated with ARVs. Finally, we could not detect viral DNA in alveolar macrophages from HIV-infected individuals who received ARVs for 3 years and had undetectable viral loads. These data demonstrate that macrophages can contain replicationcompetent virus, but may not represent a significant reservoir for HIV in vivo.