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Mechanism of Action of Isotretinoin
Published in Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish, Retinoids in Dermatology, 2019
ATRA, and especially isotretinoin, enhanced the expression of AQP3 in human keratinocytes and human skin (97,98). At the promoter level, the expression of AQP3 is induced by p53 (99,100). As a result, isotretinoin-induced upregulation of AQP3 explains isoretinoin’s adverse effect on epidermal barrier homeostasis. Aquaporin 1 (AQP1) is widely distributed in the human brain and is associated with water secretion into the subarachnoid space. Notably, AQP1 is an ATRA-inducible gene (101) that has been linked to retinoid-induced intracranial hypertension (102), which is a known potential adverse effect of systemic isotretinoin treatment (103). Stratum corneum ceramides play key functions in epidermal barrier homeostasis. There is recent evidence for the involvement of p53 in the regulation of ceramide metabolism (104).
Roles of membrane and nuclear estrogen receptors in spermatogenesis
Published in C. Yan Cheng, Spermatogenesis, 2018
Paul S. Cooke, Manjunatha K. Nanjappa, Sergei G. Tevosian, Rex A. Hess
In agreement with previous data, we observed a strong (~14-fold) downregulation of Slc9a3 RNA in NOER epididymis (Figure 9.2, Tevosian et al., unpublished) confirming that mRNA signaling is required for Slc9a3 expression. Aqp1 was also downregulated while expression of the ubiquitous Aqp4 was unchanged. Carbonic anhydrase 14 (Car14, CA-XIV), the primary carbonic anhydrase present on the luminal surface in the proximal epididymis, was unchanged, and expression of cotransporter SLC4A4 was slightly elevated (Figure 9.2). Collectively, these findings suggest that, similar to Esr1KO mice, reduced expression of Slc9A3 and Aqp1 could be involved in NOER male reproductive abnormalities.
Aquaporin-Mediated Water Transport in Intrahepatic Bile Duct Epithelial Cells
Published in Gianfranco Alpini, Domenico Alvaro, Marco Marzioni, Gene LeSage, Nicholas LaRusso, The Pathophysiology of Biliary Epithelia, 2020
Anatoliy I. Masyuk, Nicholas F. LaRusso
AQPs are divided into 2 main groups (i.e., orthodox and multifunctional AQPs) based on their abilities to transport nonionic small molecules such as urea and glycerol in addition to water.3,4 The orthodox AQPs (i.e., AQPO, AQP1, AQP2, AQP4, AQP5, AQP6, and AQP8) are water-selective.3,10 Multifunctional aquaporins (i.e., AQP3, AQP7, and AQP9), recently termed aquaglyceroporins, are permeable to water, urea, and glycerol.3,4 Moreover, it is evident now that transport properties of AQPs are even more diverse. For instance, AQP1 functions as a water channel, but may also be permeable to CO2.18,19 It has also been shown that AQP1 not only mediates the flux of water when expressed in Xenopus oocytes but also serves as a cGMP-gated ion channel.20,21 However, the passage of CO2 and ions through AQP1 is a controversial issue.22–24 Recent studies have shown that only an extremely small subpopulation of AQP1 molecules reconstituted into planar lipid bilayers may behave as ion channels (i.e., the number of ion channels is more than 1 million-fold lower than the number of water channels).25 A small degree of permeation by glycerol has also been seen in Xenopus oocytes expressing AQP1 .10 AQP6 is functionally distinct from other known AQPs. When expressed in Xenopus oocytes, AQP6 exhibits low, but significant, basal water permeability; however, when treated with the water channel inhibitor, HgCl2, the water permeability of AQP6 oocytes rapidly rises up to 10-fold and is accompanied by ion conductance.26,27 Rat AQP8 transports water, but mouse AQP8 is permeable to both water and urea.28–30 AQP9 is able to transport glycerol, urea, carbamides, polyols, purines, and pyrimidines in addition to water. 31–33 AQP 10 is a water-selective channel despite its high sequence homology to aquaglyceroporins.34
Choroid plexus and CSF: an updated review
Published in British Journal of Neurosurgery, 2022
Dana Hutton, Mohammed Gadoora Fadelalla, Avinash Kumar Kanodia, Kismet Hossain-Ibrahim
IF contributes to the CSF composition through its pressure-dependent filtration across the perivascular canalicular system.6,8,14,19,27 Water makes up ∼99% of the entire CSF volume, with solutes accounting for ∼1%.8,19,20 On this basis, Orešković and Klarica suggested it more relevant to use water movement, via aquaporins 1 and 4 (AQP1 & AQP4), to quantify and determine contributing sites of CSF production. AQP1 is highly expressed on, and specific to the ChP epithelium.6,28 AQP4, which facilitates the movement of water molecules between the cerebral vasculature and the parenchyma, is expressed on the perivascular endfeet of astrocytes.27Oshio et al. observed a ∼25% reduction in CSF formation in AQP1 knockout mice, evidence that AQP1 is involved in CSF formation across the ChP.6 However, Igarashi et al. found AQP4 played a more critical role in CSF production than AQP1, supporting the hypothesis that IF contributes significantly to the CSF volume.28
Compound Danshen Dripping Pill inhibits high altitude-induced hypoxic damage by suppressing oxidative stress and inflammatory responses
Published in Pharmaceutical Biology, 2021
Yunhui Hu, Jia Sun, Tongxing Wang, Hairong Wang, Chunlai Zhao, Wenjia Wang, Kaijing Yan, Xijun Yan, He Sun
In order to shed some further light on the possible mechanisms for CDDP protection against hypobaric hypoxia in our rat model, we determined the expression of several markers by IHC. AQP1 has a protective role by attenuating tissue edoema and inflammation (Dong et al. 2012; Ding et al. 2013). Nrf2 is a key transcription factor in anti-oxidative stress (Lisk et al. 2013). NF-κB is a heterodimeric protein composed of members of the Rel family of transcription factors and can induce a series of pro-inflammatory cytokines, including TNF-α, IL-1, IL-6 and MMP9 (Hsieh et al. 2014; Pan et al. 2020). Our results show that CDDP pre-treatment increases the levels of AQP1 and Nrf2 in both pulmonary and heart tissues (Figure 6). Importantly, and corroborating the anti-inflammatory action of CDDP demonstrated above (Figure 5(A)), NF- κB levels did not increase due to hypobaric hypoxia in the heart and lungs of rats pre-treated with CDDP (Figure 6). Thus, the anti-inflammatory action of CDDP can be attributed to its NF-κB inhibitory capacity.
Expression of aquaporins mRNAs in patients with otitis media
Published in Acta Oto-Laryngologica, 2018
Su Young Jung, Sung Su Kim, Young Il Kim, Hyung-Sik Kim, Sang Hoon Kim, Seung Geun Yeo
Our results suggested that differences in AQP mRNA expression levels among different OM types may be due to the different pathological mechanisms underlying each OM type. However, OME, COM, and choleOM, which are the subjects of this study, are classified as different diseases according to their clinical features and pathologic findings, suggesting that the expression of AQP subtypes may be affected differently in these conditions, depending on the pathology specific to each disease [1,2]. AQP1 was shown to be distributed on the surfaces of capillary endothelial cells and subepithelial fibroblasts in the ME and ET [6], consistent with results showing the presence of AQP1 in capillaries of various tissues and indicating that AQP1 regulates water transport between blood and feeder cells of these tissues. In addition, immunomorphologic studies confirmed that AQP1 is expressed on fibroblasts of the ME and that these fibroblasts maintain fluid transport and ion gradients [14]. Taken together, these results indicate that AQP1 may be involved in water homeostasis in the subepithelial milieu of the ME. Expression of AQP1 was higher in OME than in the other types of OM, presumably because the increased expression of AQP1 plays a major role in the production and accumulation of exudate in OME. However, detailed studies are required to clarify this because no studies to date have accurately determined the role of AQP in the pathophysiology of OM.