Fetoplacental unit involvement in uric acid production in women with severe preeclampsia: a prospective case control pilot study.

PURPOSE: Preeclampsia (PE) is a common complication of pregnancy that carries significant risks for both the mother and the fetus, and is frequently accompanied by hyperuricemia, yet the exact source of elevated uric acid (UA) levels remains partially elucidated. Several potential origins for increased UA levels include abnormal renal function, increased tissue breakdown, and increased activity of the enzyme Xanthine Oxidase (XO). The aim of the study was to determine serum levels of UA and XO not only in maternal serum, but also in umbilical vein (UV) and umbilical artery (UA) and explore their possible role in PE development. METHODS: A prospective case-control pilot study was conducted in women who were found positive for PE with severe features, and had elevated UA levels above 6 mg/dL, with normotensive pregnant women serving as controls. Renal function, UA and XO levels were measured in maternal, UV and UA serums immediately after delivery. They were then compared between PE (n = 21) and control (n = 18) groups, as well as across all mediums (maternal, UV and UA) among the total study sample (N = 39). Diastolic blood pressure (DBP) was also measured immediately following delivery. RESULTS: The mean serum maternal creatinine levels did not differ significantly between groups (0.65 ± 0.03 vs 0.6 ± 0.07, p = 0.13). Both mean maternal serum UA and XO concentrations were higher in PE group than in control (7.3 ± 1.2 vs 4.2 ± 0.9, p < 0.01 and 3.6 ± 3.5 Vs 1.7 ± 0.8, p < 0.01, respectively). The mean UV and UA serum XO concentrations were significantly higher in PE group compared to control (4.2 ± 3.6 vs 2.2 ± 1.4, p < 0.01 and 4.2 ± 3.6 vs 2.1 ± 1.5, p < 0.01, respectively). Polynomial fit correlation test demonstrated a significant association between maternal DBP and UV XO concentration for all the total study participants (p = 0.03). CONCLUSION: Despite preserved renal functions, UA and XO levels were elevated in women with PE. Importantly, this pattern was found to be applied to the feto-placental unit as well, which may indicate an active involvement of the fetus in the hypoxic process. Further study is needed to clarify the possible role of the feto-placental unit in pregnancies complicated by PE.

One-year dynamics of antibody titers after three doses of SARS-CoV-2 BNT162b2 vaccine.

BACKGROUND: A third dose of the BNT162b2 SARS-CoV-2 vaccine leads to a significant increase in antibody levels, however, concerns regarding the long-term persistence of this response exist. We assessed the humoral response for one year following vaccination. METHODS: A prospective study among immunocompetent healthcare workers (HCW) who received three doses of BNT162b2. anti-spike antibody titers were measured at six predefined timepoints, from before the second vaccine dose, and up to one year afterwards, which is 4-6 months after the third dose. HCW with a history of SARS-CoV-2 infection were excluded. RESULTS: Seventy-six HCW had all the six serological measurements. Antibody titers significantly increased shortly following the third vaccine dose, and while declining, remained higher from all previous measurements for up to six months. CONCLUSIONS: A third dose of BNT162b2 leads to a profound humoral response, which remains significantly higher than previous measurements, even after 6 months.

Gi and RGS proteins provide biochemical control of androgen receptor nuclear exclusion.

Nuclear localization of androgen receptors (ARs) is essential for their activity. Melatonin induces AR nuclear exclusion via increase in cGMP, calcium, and protein kinase C (PKC) activation, presumably through G-protein(s). The effects of regulators of G-protein signaling (RGS) on AR localization were studied in AR-expressing PC3 cells. Gi-specific RGS10 inhibited melatonin but not cGMP-induced AR nuclear exclusion, independent of androgen. No evidence for Gq activation by melatonin was found. However, Gi/Gq-selective RGS4 inhibited AR nuclear exclusion downstream of PKC activation--an effect that was abrogated by constitutively active Gq. RGS10 and RGS4, but not RGS2, ablated the inhibitory effects of melatonin on AR reporter gene activity. For the first time, these data show regulation by Gi and Gi-specific RGS protein-mediated AR nuclear exclusion, which is potentially important in the treatment of AR-dependent cancers and neurodegenerative disorders. They also reveal a role for a Gq protein downstream of PKC activation in AR nuclear localization.

Nuclear exclusion of the androgen receptor by melatonin.

Androgen receptors (AR) play a crucial role in androgen-mediated processes and prostate cancer progression. The pineal hormone melatonin attenuates the androgen-dependent growth of benign and cancer prostate epithelial cells in vitro and may reverse clinical resistance to androgen ablation therapy in patients progressing on gonadotropin releasing hormone (GnRH) analogue. Where along the AR cascade does melatonin act remains to be determined. The effects of melatonin on AR localization, level and activity were assessed using androgen-insensitive prostate carcinoma PC3 cells stably transfected with a wild-type AR-expressing vector (PC3-AR).AR was localized to the PC3-AR cell nucleus in the absence of dihydrotestosterone (DHT). Melatonin caused a robust exclusion of the AR from the cell nucleus to the cytoplasm. The nuclear export inhibitor, leptomycin B prevented this process. The exclusion was selective since melatonin had no such effect on the nuclear localization of estrogen receptors alpha (ERalpha) in these cells. Melatonin also caused nuclear exclusion of the AR in the presence of DHT. In addition, it attenuated androgen induced reporter gene activity in PC3 cells co-transfected with the human AR and AR reporter plasmids. Elevated androgen concentrations counteracted melatonin's effects. Melatonin did not decrease AR level or androgen binding in the cells. The nuclear localization of the AR is a hallmark of its cellular activity. These data point to AR nuclear exclusion as a possible mechanism to attenuate androgen responses in target tissues.

Differential regulation by melatonin of cell growth and androgen receptor binding to the androgen response element in prostate cancer cells.

OBJECTIVES: The pineal hormone melatonin inhibits the growth of benign human prostate epithelial cells and the androgen-dependent prostate cancer LNCaP cells. In the androgen-nonresponsive prostate carcinoma PC3 cells melatonin inhibits cell growth only at high but not low cell density. We have recently found that melatonin causes nuclear exclusion of the AR and attenuates it transcriptional activity in LNCaP cells as well as PC3 cells stably transfected with a wild type AR expressing vector (PC3-AR). The aim of this study was to investigate whether melatonin inhibits effects of AR on cell growth in PC3-AR cells and whether inhibition of AR DNA binding is involved. METHODS: The effects of androgen, melatonin and their combination on the growth of the PC3-AR cells and on AR DNA binding in PC3-AR and LNCaP cells were studied. RESULTS: DHT suppressed cell growth in the PC3-AR cells and enhanced AR binding to the androgen responsive element (ARE). Melatonin had no effect on cell growth in the absence of DHT but counteracted the androgen-induced inhibition at low androgen concentrations. Melatonin did not suppress and even slightly enhanced the capacity of AR binding to the ARE in the PC3-AR as well as in LNCaP cells. CONCLUSIONS: Attenuation by melatonin of AR activity in the prostate cancer cells is not due to suppression of AR binding to the ARE, and is presumably caused by its effects on AR protein interaction and intracellular trafficking.

Differential effects of melatonin and its downstream effector PKCalpha on subcellular localization of RGS proteins.

Regulators of G protein signaling (RGS) are proteins that bind specifically to activated Galpha subunits of heterotrimeric G proteins to terminate signaling by both Galpha and Gbetagamma subunits. Signal-induced RGS redistribution may affect their activity in G protein-mediated signaling. We have previously shown that melatonin and the cell permeable cGMP analog 8-bromo cGMP, which lead to protein kinase C (PKC) activation, enhanced cytoplasmic distribution of RGS10 and RGS2 in prostate carcinoma PC3-AR cells. In the present study, we transfected PC3-AR cells with myc-tagged Galphai/Galphaq specific RGS proteins RGS2, RGS4 and RGS10 and examined the effects of melatonin, 8-bromo cGMP and PKC inhibitors on their nuclear-cytoplasmic partitioning. RGS10 and RGS2 were predominantly localized in the nucleus and perinuclear regions whereas RGS4 was mostly cytoplasmic in the PC3-AR cells. Melatonin and the cell permeable cGMP analog 8-bromo cGMP, previously found to activate PKCalpha in the PC3-AR cells, enhanced cytoplasmic localization of RGS10 and RGS2 but induced nuclear accumulation of RGS4. The isozyme specific PKC inhibitor GO6976 (PKCalpha and PKCbeta1) but not hispidin (PKCbeta) negated the effects of melatonin on RGS10, RGS2 and RGS4 localization. These findings indicate that PKCalpha, a downstream effector of the melatonin receptor, differentially affects nuclear/cytoplasmic localization of both Galphai and Galphaq specific RGS proteins. These observations provide further insight into melatonin's ability to fine-tune multiple membrane G-proteins signaling in cells.