Plant aquaporins:Their roles beyond water transport

Compared to other organisms,plants have evolved a greater number of aquaporins with diverse substrates and functions to adapt to ever-changing environmental and internal stimuli for growth and development.Although aquaporins were initially identified as channels that allow water molecules to cross biological membranes,progress has been made in identifying various novel permeable substrates.Many studies have characterized the versatile physiological and biophysical functions of plant aquaporins.Here,we review the recent reports that highlight aquaporin-facilitated regulation of major physiological processes and stress tolerance throughout plant life cycles as well as the potential prospects and possibilities of applying aquaporins to improve agricultural productivity,food quality,environmental protection,and ecological conservation.

Global characterization of OsPIP aquaporins reveals that the H_(2)O_(2)transporter OsPIP2;6 increases resistance to rice blast

Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress.To elucidate their roles in plant immunity to pathogen attack,we characterized the expression patterns,subcellular localizations,and H_(2)O_(2)-transport ability of 11 OsPIPs in rice(Oryza sativa),and identified OsPIP2;6 as necessary for rice disease resistance.OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H_(2)O_(2).Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae,indicating a positive function in plant immunity.OsPIP2;6 interacts with OsPIP2;2,which has been reported to increase rice resistance to pathogens via H_(2)O_(2)transport.Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant–pathogen interaction.

Aquaglyceroporins but not orthodox aquaporins are involved in the cryotolerance of pig spermatozoa

Background:Aquaporins(AQPs)are a family of transmembrane water channels that includes orthodox AQPs,aquaglyceroporins(GLPs)and super AQPs.AQP3,AQP7,AQP9 and AQP11 have been identified in boar sperm,and they are crucial for sperm maturation and osmoregulation.Water exchange is an important event in cryopreservation,which is the most efficient method for long-term storage of sperm.However,the freezethaw process leads to sperm damage and a loss of fertilizing potential.Assuming that the quality of frozenthawed sperm partially depends on the regulation of osmolality variations during this process,AQPs might play a crucial role in boar semen freezability.In this context,the aim of this study was to unravel the functional relevance of the different groups of AQPs for boar sperm cryotolerance through three different inhibitors.Results:Inhibition of different groups of AQPs was found to have different effects on boar sperm cryotolerance.Whereas the use of 1,3-propanediol(PDO),an inhibitor of orthodox AQPs and GLPs,decreased total motility(P<0.05),it increased post-thaw sperm viability,lowered membrane lipid disorder and increased mitochondrial membrane potential(MMP)(P<0.05).When acetazolamide(AC)was used as an inhibitor of orthodox AQPs,the effects on post-thaw sperm quality were restricted to a mild increase in MMP in the presence of the intermediate concentration at 30 min post-thaw and an increase in superoxide levels(P<0.05).Finally,the addition of phloretin(PHL),a GLP inhibitor,had detrimental effects on post-thaw total and progressive sperm motilities,viability and lipid membrane disorder(P<0.05).Conclusions:The effects of the different inhibitors suggest that GLPs rather than orthodox AQPs are relevant for boar sperm freezability.Moreover,the positive effect of PDO on sperm quality suggests a cryoprotective role for this molecule.

Auphen and dibutyryl cAMP suppress growth of hepatocellular carcinoma by regulating expression of aquaporins 3 and 9 in vivo

AIM: To investigate whether the regulation of aquaporin 3(AQP3) and AQP9 induced by Auphen and dibutyryl c AMP(dbc AMP) inhibits hepatic tumorigenesis. METHODS: Expression of AQP3 and AQP9 was detected by Western blot, immunohistochemistry(IHC), and RT-PCR in HCC samples and paired non-cancerous liver tissue samples from 30 hepatocellular carcinoma(HCC) patients. A xenograft tumor model was used in vivo. Nine nude mice were divided into control, Auphen-treated, and dbc AMP-treated groups(n = 3 for each group). AQP3 and AQP9 protein expression after induction of xenograft tumors was detected by IHC and m RNA by RT-PCR analysis. The terminal deoxynucleotidyl transferase-mediated d UTP nick end labeling assay and histological evaluation were used to detect apoptosis of tumor cells, and the concentration of serum α-fetoprotein(AFP) was measured using RTPCR and an ELISA kit.RESULTS: The volumes and weights of tumors decreased significantly in the Auphen- and dbc AMP-treated mice compared with the control mice(P < 0.01). The levels of AQP3 were significantly lower in the Auphen treatment group, and levels of AQP9 were significantly higher in thedbc AMP treatment mice than in the control mice(P < 0.01). The reduction of AQP3 by Auphen and increase of AQP9 by dbc AMP in nude mice suppressed tumor growth of HCC, which resulted in reduced AFP levels in serum and tissues, and apoptosis of tumor cells in the Auphen- and dbc AMP-treated mice, when compared with control mice(P < 0.01). Compared with para-carcinoma tissues, AQP3 expression increased in tumor tissues whereas the expression of AQP9 decreased. By correlating clinicopathological and expression levels, we demonstrated that the expression of AQP3 and AQP9 was correlated with clinical progression of HCC and disease outcomes. CONCLUSION: AQP3 increases in HCC while AQP9 decreases. Regulation of AQP3 and AQP9 expression by Auphen and dbc AMP inhibits the development and growth of HCC.

Hetong decoction(和通汤)relieves loperamide-induced constipation in rats by regulating expression of aquaporins

OBJECTIVE:To investigate whether Hetong decoction(和通汤,HTT)alleviates constipation via regulating AQPs expression.METHODS:Constipation in rats was induced by loperamide,and rats were randomly assigned into model(saline),HHT-low(95 g/kg),HTT-medium(190 g/kg),HTT-high(380 g/kg)and positive control(mosapride)groups.Then the defecation function,the concentration of serum arginine vasopressin(AVP)and cyclic adenosine monophosphate(cAMP),and the expression of AQP3 and AQP8 in colon tissues were assessed.NCM460 colon cells with AQP3 and AQP8 knockdown or overexpression were exposed to serum from rats that received low or high dose of HTT,followed by detection of AQP3 and AQP8 expression.RESULTS:The model group showed lower fecal weight and water content,weaker intestinal transit,higher serum concentration of AVP and cAMP,increased proximal and distal AQP8 expression,increased proximal but decreased distal AQP3 expression.However,these trends were reversed in both the HTT group(low,medium and high dose)and the positive control group.In NCM460 cells,HTT dose-dependently stabilized AQP3 and AQP8 expression under AQP3/8 plasmid interference or overexpression.CONCLUSIONS:HTT relieves constipation in rats through regulating AQP3 and AQP8 expression.

Effects of electroacupuncture on cochlear morphology and expression of aquaporins in rats with AVP-induced endolymphatic hydrops

Objective: The objective of this study was to investigate the effects of EA on EH and the regulation of AQP2 and AQP7 protein expression in rats.Methods: Twenty-four rats were allocated randomly to four groups of blank group, EH group,EH+tolvaptan group and EH + EA group(n = 6 per group). EH rat model was established by intraperitoneally injection of arginine vasopressin(AVP). EA was administered at acupoints "Baihui(百会 GV 20)"and "Tinggong(听宫 SI 19)". Rats in the EH + tolvaptan group and EH+ EA group were treated with tolvaptan and EA, respectively, after EH establishment. Hematoxylin-eosin staining was used to measure the cochlear hydrops degree, and then the ratio of scala media(SM) area to SM + scala vestibuli(SV) area(R value) was calculated. Immunohistochemical method was used to observe AQP2/AQP7 protein expression in the rat cochlear lateral wall after treatment.Results: ①There was no endolymphatic hydrops in the blank group. Reissner' s membrane was extended markedly and bulged into SV in cochleae of the EH group and endolymphatic hydrops was noted. Statistical analysis revealed that R value in the EH group showed a significant increase compared with that in the blank group(0.42 ± 0.02 vs. 0.31 ± 0.05, P=0.000). The distension of Reissner's membrane was less obvious in the EH + tolvaptan group and EH + EA group when compared with the EH group. R value in the EH + tolvaptan group and the EH + EA group was significantly less than that in EH group(0.32±0.04 vs. 0.42 ± 0.02, =0.001;0.35 ± 0.05 vs. 0.42 ± 0.02, P=0.012). The degree of the hydrops in the EH + EA group was not different from that in the EH + tolvaptan group(0.35 ± 0.05 vs. 0.32 ±0.04,P= 1.000). ②The AQP2 protein expression in the rat cochlear lateral wall of EH group was significantly increased when compared with the blank group(12.74 ± 5.18 vs. 5.92 ± 1.52, P = 0.014). The AQP2 protein expression in the rat cochlear lateral wall of EH + tolvaptan group and EH + EA group were all lower than that of the EH group(6.52 ± 2.73 vs. 12.74 ± 5.18. P = 0.029;6.95 ± 3.10 vs. 12.74 ± 5.18, P = 0.047).The AQP2 protein expression in the rat cochlear lateral wall of EH + EA group was not different from that in the EH + tolvaptan group(6.95 ± 3.10 vs. 6.52 ± 2.73, P= 1.000).③The AQP7 protein expression in the rat cochlear lateral wall of EH group was significantly increased when compared with the blank group(30.32 ± 6.39 vs 16.64 ± 3.21, P=0.000). The AQP7 protein expression in the rat cochlear lateral wall of EH + tolvaptan group and EH + EA group were all lower than that of the EH group(18.32 ± 2.45 vs.30.32 ± 6.39, P= 0.001;19.54 ± 4.61 vs. 30.32 ± 6.39, P= 0.003). The AQP7 protein expression in the rat cochlear lateral wall of EH + EA group was not different from that in the EH + tolvaptan group(19.54 ±4.61 vs. 18.32 ± 2.45, P= 1.000).Conclusions: These results indicate that repeated EA stimulation exerted the same effects as tolvaptan application on AQPs levels and subsequent aquaretic effects. And dehydrating effect of EA on the inner ear might be associated with its down-regulation of both AQP2 and AQP7 protein expression, thereby provide a potential molecular mechanism involved in the treatment of Meniere's disease by EA.

The regulatory roles of aquaporins in the digestive system

Aquaporins(AQPs)are highly conserved small transmembrane proteins,which are responsible for the water transport across the cell membrane.AQPs are abundantly expressed in numerous types of cells such as epithelial and endothelial cells.The expression of AQP-1,-3,-4,-5,-8 and-9 were found in the digestive system,where these six AQP isoforms serve essen-tial roles including mediating the transmembrane water transport and regulating the secretion of gastrointestinal(GI)fluids,consequently facilitating the digestion and absorption of GI con-tents.In addition,the expression levels of AQPs are controlled by various factors,and AQPs can stimulate numerous signaling pathways;however,aberrant expression of AQPs in the GI tracts are associated with the initiation and development of numerous diseases.Thus,this re-view provides an overview of the expression and functions of AQPs in the digestive system.

The Correlation between Nutrition and Transport Mechanism under Abiotic Stress in Plants: A Comprehensive Review

Variations in the nutrients and water that plants require for metabolism,development,and the maintenance of cellular homeostasis are the main causes of abiotic stress in plants.It has,however,hardly ever been studied how these transporter proteins,such as aquaporin which is responsible for food and water intake in cell plasma mem-branes,interact with one another.This review aims to explore the interactions between nutrient transporters and aquaporins during water and nutrient uptake.It also investigates how symbiotic relationships influence the plant genome’s responses to regulatory processes such as photoperiodism,senescence,and nitrogenfixation.These responses are observed in reaction to various abiotic stresses.For instance,plasma membrane transporters are upregulated during macronutrient insufficiency,tonoplast transporters are overexpressed,and aquaporins are downregulated in micronutrient deficiency.Additionally,tolerant plants often exhibit increased expression of nutrient transporters and aquaporins in response to drought,salt,and cold temperatures.To better comprehend plant stress tolerance to abiotic challenges including starvation,K famine,salt,and freezing temperatures,both classes of nutrient and water transporters should be considered at the same time.

Research Progress on the Pathogenesis of Acute Lung Injury(ALI)

In this review,the databases searched were PubMed and Web of Science.It is believed that the main causes of acute lung injury(ALI)and acute respiratory distress syndrome(ARDS)are inflammatory response disorders,excessive oxidative stress,cell death,endoplasmic reticulum stress,coagulation dysfunction,and weakened aquaporin function.

Deferential responses of plant aquaporins(AQPs) to osmotic and salt stresses

With the support of the National Natural Science Foundation of China,Prof.Ye Qing’s laboratory at South China Botanical Garden,Chinese Academy of Sciences,reported differential regulatory mechanisms of AQPs in mediating plant water transport under osmotic or salt stresses,which was published in Plant,Cell and Environment(2014,doi:10.1111/pce.12319).

Single Mutations in the Transmembrane Domains of Maize Plasma Membrane Aquaporins Affect the Activity of Monomers within a Heterotetramer

Aquaporins are channels facilitating the diffusion of water and/or small uncharged solutes ecross biological membranes. They assemble as homotetramers but some of them also form heterotetramers, especially in plants. In Zea mays, aquaporins belonging to the plasma membrane intrinsic protein （PIP） subfamily are clustered into two groups, PIP1 and PIP2, which exhibit different water-channel activities when expressed in Xenopus oocytes. When PIP1 and PIP2 isoforms are co-expressed, they physically interact to modulate their subcellular localization and channel activity. Here, we demonstrated by affinity chromatography purification that, when co-expressed in Xenopus oocytes, the maize PIP1;2 and PIP2;5 isoforms assemble as homo- and heterodimers within heterotetramers. We built the 3D structure of such heterotetramers by comparative modeling on the basis of the spinach SoPIP2;1 X-ray structure and identified amino acid residues in the transmembrane domains which putatively interact at the interfaces between monomers. Their roles in the water-channel activity, subcellular localization, protein abundance, and physical interac- tion were investigated by mutagenesis. We highlighted single-residue substitutions that either inactivated PIP2;5 or activated PIP1;2 without affecting their interaction. Interestingly, the Phe220Ala mutation in the transmembrane domain 5 of PIP1 ;2 activated its water-channel activity and, at the same time, inactivated PIP2;5 within a heterotetramer. Altogether, these data contribute to a better understanding of the interaction mechanisms between PIP isoforms and the role of heterotetramerization on their water-channel activity.

Progress on the Application of Aquaporins in Chinese Medicine

Aquapodns are a group of membrane proteins, which are known as the passages of water molecules transforming through the biological membrane lipid bilayer and distributing in almost all of the organs and tissues of living creatures. Aquaporins play important roles in maintaining water balance and internal environment stability. As a new entry point, aquaporins are involved in the researches on water metabolism, physiological regulation and pathological essence in viscera-state more and more widely in recent years. The literature on traditional Chinese medical studies, which related to aquaporins and were published in the last decade, was reviewed and the progress on application of aquaporin in Chinese medicine was summarized in this paper.

Ontogeny of the mammalian kidney:expression of aquaporins 1,2,3,and 4

Background:Determining the expression and functions of aquaporins(AQPs)in the adult kidney has generated important information about the roles of this protein family in the renal regulation of water homeostasis.However,limited information describes the expression of AQPs in fetal kidneys,and most reports on fetal renal AQPs originate from animal studies.Although there are the maturation and regulation of the renalconcentrating mechanism,the ways in which changes in the expression of AQPs contribute to the formation of urine during the perinatal period remain unclear.Data sources:This review summarizes current knowledge about the spatial and temporal expression patterns of AQP1,AQP2,AQP3,and AQP4 in the fetal and postnatal kidneys in different animal species and in human beings.Results:AQP1 and AQP2 expression can be detected earlier in gestation in human beings and sheep compared with mice and rats.AQP1 expression is detected earlier in the proximal tubules than the expression of AQP2,AQP3,and AQP4 in the collecting ducts.Conclusion:Further studies investigating the regulation of AQPs during kidney development may provide insights into normal water-handling mechanisms and the pathophysiology of fetal kidneys,which may determine new directions for the clinical treatment of kidney diseases.

Subcellular Redistribution of Root Aquaporins nduced by Hydrogen Peroxide

Aquaporins are water channel proteins that mediate the fine-tuning of cell membrane water permeability during development or in response to environmental stresses. The present work focuses on the oxidative stress-induced redistribution of plasma membrane intrinsic protein （PIP） aquaporins from the plasma membrane （PM） to intracellular membranes. This process was investigated in the Arabidopsis root. Su- crose density gradient centrifugation showed that exposure of roots to 0.5 mM H2O2 induces significant depletion in PM fractions of several abundant PIP homologs after 15 rain. Analyses by single-particle tracking and fluorescence correlative spectroscopy showed that, in the PM of epidermal cells, H2O2 treat- ment induces an increase in lateral motion and a reduction in the density of a fluorescently tagged form of the prototypal AtPIP2;1 isoform, respectively. Co-expression analyses of AtPIP2;1 with endomembrane markers revealed that H2O2 triggers AtPIP2;1 accumulation in the late endosomal compartments. Life- time analyses established that the high stability of PIPs was maintained under oxidative stress conditions, suggesting that H2O2 triggers a mechanism for intracellular sequestration of PM aquaporins without further degradation. In addition to information on cellular regulation of aquaporins, this study provides novel and complementary insights into the dynamic remodeling of plant internal membranes during oxida- tive stress responses.

Lights at night:does photobiomodulation improve sleep?

Sleep is a critical part of our daily routine.It impacts every organ and system of our body,from the brain to the heart and from cellular metabolism to immune function.A consistent daily schedule of quality of sleep makes a world of difference to our health and well-being.Despite its importance,so many individuals have trouble sleeping well.Poor quality sleep has such a detrimental impact on many aspects of our lives;it affects our thinking,learning,memory,and movements.Further,and most poignantly,poor quality sleep over time increases the risk of developing a serious medical condition,including neurodegenerative disease.In this review,we focus on a potentially new non-pharmacological treatment that improves the quality of sleep.This treatment,called photobiomodulation,involves the application of very specific wavelengths of light to body tissues.In animal models,these wavelengths,when applied at night,have been reported to stimulate the removal of fluid and toxic waste-products from the brain;that is,they improve the brain’s inbuilt house-keeping function.We suggest that transcranial nocturnal photobiomodulation,by improving brain function at night,will help improve the health and well-being of many individuals,by enhancing the quality of their sleep.

A cluster of mutagenesis revealed an osmotic regulatory role of the OsPIP1 genes in enhancing rice salt tolerance

Aquaporins play important regulatory roles in improving plant abiotic stress tolerance.To better understand whether the Os PIP1 genes collectively dominate the osmotic regulation in rice under salt stress,a cluster editing of the Os PIP1;1,Os PIP1;2 and Os PIP1;3 genes in rice was performed by CRISPR/Cas9 system.Sequencing showed that two mutants with Cas9-free,line 14 and line 18 were successfully edited.Briefly,line 14 deleted a single C base in both the Os PIP1;1 and Os PIP1;3 genes,and inserted a single T base in the Os PIP1;2 gene,respectively.While line 18 demonstrated an insertion of a single A base in the Os PIP1;1gene and a single T base in both the Os PIP1;2 and Os PIP1;3 genes,respectively.Multiplex editing of the Os PIP1 genes significantly inhibited photosynthetic rate and accumulation of compatible metabolites,but increased MDA contents and osmotic potentials in the mutants,thus delaying rice growth under salt stress.Functional loss of the Os PIP1 genes obviously suppressed the expressions of the Os PIP1,Os SOS1,Os CIPK24 and Os CBL4 genes,and increased the influxes of Na+and effluxes of K^(+)/H^(+)in the roots,thus accumulating more Na+in rice mutants under salt stress.This study suggests that the Os PIP1 genes are essential modulators collectively contributing to the enhancement of rice salt stress tolerance,and multiplex editing of the Os PIP1 genes provides insight into the osmotic regulation of the PIP genes.

Inhibiting phosphatase and actin regulator 1 expression is neuroprotective in the context of traumatic brain injury

Studies have found that the phosphatase actin regulatory factor 1 expression can be related to stroke,but it remains unclear whether changes in phosphatase actin regulatory factor 1 expression also play a role in traumatic brain injury.In this study we found that,in a mouse model of traumatic brain injury induced by controlled cortical impact,phosphatase actin regulatory factor 1 expression is increased in endothelial cells,neurons,astrocytes,and microglia.When we overexpressed phosphatase actin regulatory factor 1 by injection an adeno-associated virus vector into the contused area in the traumatic brain injury mice,the water content of the brain tissue increased.However,when phosphatase actin regulatory factor 1 was knocked down,the water content decreased.We also found that inhibiting phosphatase actin regulatory factor 1 expression regulated the nuclear factor kappa B signaling pathway,decreased blood-brain barrier permeability,reduced aquaporin 4 and intercellular adhesion molecule 1 expression,inhibited neuroinflammation,and neuronal apoptosis,thereby improving neurological function.The findings from this study indicate that phosphatase actin regulatory factor 1 may be a potential therapeutic target for traumatic brain injury.

Fecal microbiota transplantation alleviates experimental colitis through the Toll-like receptor 4 signaling pathway

BACKGROUND Fecal microbiota transplantation(FMT)has shown promising therapeutic effects on mice with experimental colitis and patients with ulcerative colitis(UC).FMT modulates the Toll-like receptor 4(TLR4)signaling pathway to treat some other diseases.However,it remains unknown whether this modulation is also involved in the treatment of UC.AIM To clarify the necessity of TLR4 signaling pathway in FMT on dextran sodium sulphate(DSS)-induced mice and explain the mechanism of FMT on UC,through association analysis of gut microbiota with colon transcriptome in mice.METHODS A mouse colitis model was constructed with wild-type(WT)and TLR4-knockout(KO)mice.Fecal microbiota was transplanted by gavage.Colon inflammation severity was measured by disease activity index(DAI)scoring and hematoxylin and eosin staining.Gut microbiota structure was analyzed through 16S ribosomal RNA sequencing.Gene expression in the mouse colon was obtained by transcriptome sequencing.RESULTS The KO(DSS+Water)and KO(DSS+FMT)groups displayed indistinguishable body weight loss,colon length,DAI score,and histology score,which showed that FMT could not inhibit the disease in KO mice.In mice treated with FMT,the relative abundance of Akkermansia decreased,and Lactobacillus became dominant.In particular,compared with those in WT mice,the scores of DAI and colon histology were clearly decreased in the KO-DSS group.Microbiota structure showed a significant difference between KO and WT mice.Akkermansia were the dominant genus in healthy KO mice.The ineffectiveness of FMT in KO mice was related to the decreased abundance of Akkermansia.Gene Ontology enrichment analysis showed that differentially expressed genes between each group were mainly involved in cytoplasmic translation and cellular response to DNA damage stimulus.The top nine genes correlating with Akkermansia included Aqp4,Clca4a,Dpm3,Fau,Mcrip1,Meis3,Nupr1 L,Pank3,and Rps13(|R|>0.9,P<0.01).CONCLUSION FMT may ameliorate DSS-induced colitis by regulating the TLR4 signaling pathway.TLR4 modulates the composition of gut microbiota and the expression of related genes to ameliorate colitis and maintain the stability of the intestinal environment.Akkermansia bear great therapeutic potential for colitis.

Aquaporin,beyond a transporter

Aquaporins(AQPs)are one of the most ancient superfamily proteins,which are essential for maintaining the fluid homeostasis of most organisms against various environments.Here,the latest findings for function of AQPs in cell signal transduction in plants are summarized.We also put forward several issues that still need to be addressed in the future.

The therapeutic mechanism of dexamethasone in lung injury induced by hydrogen sulfide

The lung is one of the primary target organs of hydrogen sulfide(H2S),as exposure to H2S can cause acute lung injury(ALI)and pulmonary edema.Dexamethasone(Dex)exerts a protective effect on ALI caused by exposure to toxic gases and is commonly used in the clinic;however,the underlying mechanisms remain elusive,and the dose is unclear.Methods:In vivo experiments:divided C57BL6 mice into 6 groups at random,12 in each group.The mice were exposed to H2S for 3 h and 5 or 50 mg/kg Dex pretreated before exposure,sacrificed 12 h later.The morphological changes of HE staining and the ultrastructural changes of lungs under transmission electron microscopy were evaluated.The wet/dry ratio of lung tissue was measured.Bronchial alveolar lavage fluid(BALF)protein content and lung permeability index were detected.The expression of AQP5 protein was measured by immunohistochemistry and Western Blot(WB).In vitro experiments:divided human lung adenocarcinoma cell line A549 into 4 groups.1μmol/L dexamethasone was added to pre-incubation.The WB analyzed the protein of p-ERK1/2,p-JNK,and p-p38 in MAPK pathway after 1 h of NaHS exposure;six hours after NaHS exposure,the AQP5 protein was measured by WB.Results:Dex treatment could significantly attenuate the H2S-induced destruction to the alveolar wall,increase the wet-to-dry weight ratio and decrease pulmonary permeability index,with high-dose dexamethasone seemingly functioning better.Additionally,our previous studies showed that aquaporin 5(AQP 5),a critical protein that regulates water flux,decreased both in a mouse and cell model following the exposure to H2S.This study indicates that tThe decrease in AQP 5 can be alleviated by Dex treatment.Additionally,the mitogen activated protein kinase(MAPK)pathway may be involved in the protective effects of Dex in ALI caused by exposure to H2S since H2Sinduced MAPK activation could be inhibited by Dex.Conclusion:The present results indicate that AQP 5 may be considered a therapeutic target for Dex in H2S or other hazardous gases-induced ALI.