Targeting AQP9 enhanced the anti-TNF therapy response in Crohn's disease by inhibiting LPA-hippo pathway.

Although anti-TNF antibodies are extensively used to treat Crohn's disease (CD), a significant proportion of patients, up to 40%, exhibit an inadequate response to this therapy. Our objective was to identify potential targets that could improve the effectiveness of anti-TNF therapy in CD. Through the integration and analysis of transcriptomic data from various CD databases, we found that the expression of AQP9 was significantly increased in anti-TNF therapy-resistant specimens. The response to anti-TNF therapy in the CD mouse model was significantly enhanced by specifically inhibiting AQP9. Further experiments found that the blockade of AQP9, which is dominantly expressed in macrophages, decreased inflamed macrophage functions and cytokine expression. Mechanistic studies revealed that AQP9 transported glycerol into macrophages, where it was metabolized to LPA, which was further metabolized to LPA, resulting in the activation of the LPAR2 receptor and downstream hippo pathway, finally promoting the expression of cytokines, especially IL23 and IL1ß⊡ Taken together, the expansion of AQP9+ macrophages is associated with resistance to anti-TNF therapy in Crohn's disease. These findings indicated that AQP9 could be a potential target for enhancing anti-TNF therapy in Crohn's disease.

AQP3 and AQP9-Contrary Players in Sepsis?

Sepsis involves an immunological systemic response to a microbial pathogenic insult, leading to a cascade of interconnected biochemical, cellular, and organ-organ interaction networks. Potential drug targets can depict aquaporins, as they are involved in immunological processes. In immune cells, AQP3 and AQP9 are of special interest. In this study, we tested the hypothesis that these aquaporins are expressed in the blood cells of septic patients and impact sepsis survival. Clinical data, routine laboratory parameters, and blood samples from septic patients were analyzed on day 1 and day 8 after sepsis diagnosis. AQP expression and cytokine serum concentrations were measured. AQP3 mRNA expression increased over the duration of sepsis and was correlated with lymphocyte count. High AQP3 expression was associated with increased survival. In contrast, AQP9 expression was not altered during sepsis and was correlated with neutrophil count, and low levels of AQP9 were associated with increased survival. Furthermore, AQP9 expression was an independent risk factor for sepsis lethality. In conclusion, AQP3 and AQP9 may play contrary roles in the pathophysiology of sepsis, and these results suggest that AQP9 may be a novel drug target in sepsis and, concurrently, a valuable biomarker of the disease.

Aquaporins: Gatekeepers of Fluid Dynamics in Traumatic Brain Injury.

Aquaporins (AQPs), particularly AQP4, play a crucial role in regulating fluid dynamics in the brain, impacting the development and resolution of edema following traumatic brain injury (TBI). This review examines the alterations in AQP expression and localization post-injury, exploring their effects on brain edema and overall injury outcomes. We discuss the underlying molecular mechanisms regulating AQP expression, highlighting potential therapeutic strategies to modulate AQP function. These insights provide a comprehensive understanding of AQPs in TBI and suggest novel approaches for improving clinical outcomes through targeted interventions.

Aquaporin 2 in Cerebral Edema: Potential Prognostic Marker in Craniocerebral Injuries.

Despite continuous medical advancements, traumatic brain injury (TBI) remains a leading cause of death and disability worldwide. Consequently, there is a pursuit for biomarkers that allow non-invasive monitoring of patients after cranial trauma, potentially improving clinical management and reducing complications and mortality. Aquaporins (AQPs), which are crucial for transmembrane water transport, may be significant in this context. This study included 48 patients, with 27 having acute (aSDH) and 21 having chronic subdural hematoma (cSDH). Blood plasma samples were collected from the participants at three intervals: the first sample before surgery, the second at 15 h, and the third at 30 h post-surgery. Plasma concentrations of AQP1, AQP2, AQP4, and AQP9 were determined using the sandwich ELISA technique. CT scans were performed on all patients pre- and post-surgery. Correlations between variables were examined using Spearman's nonparametric rank correlation coefficient. A strong correlation was found between aquaporin 2 levels and the volume of chronic subdural hematoma and midline shift. However, no significant link was found between aquaporin levels (AQP1, AQP2, AQP4, and AQP9) before and after surgery for acute subdural hematoma, nor for AQP1, AQP4, and AQP9 after surgery for chronic subdural hematoma. In the chronic SDH group, AQP2 plasma concentration negatively correlated with the midline shift measured before surgery (Spearman's ρ -0.54; p = 0.017) and positively with hematoma volume change between baseline and 30 h post-surgery (Spearman's ρ 0.627; p = 0.007). No statistically significant correlation was found between aquaporin plasma levels and hematoma volume for AQP1, AQP2, AQP4, and AQP9 in patients with acute SDH. There is a correlation between chronic subdural hematoma volume, measured radiologically, and serum AQP2 concentration, highlighting aquaporins' potential as clinical biomarkers.

LncRNA-mRNA co-expression analysis reveals aquaporin-9-promoted neutrophil extracellular trap formation and inflammatory activation in sepsis.

Sepsis is a life-threatening condition caused by an excessive inflammatory response to an infection. However, the precise regulatory mechanism of sepsis remains unclear. Using a strand-specific RNA-sequencing, we identified 115 hub differentially expressed long noncoding RNAs (lncRNAs) and 443 mRNAs in septic patients, primarily participated in crucial pathways including neutrophil extracellular trap (NET) formation and toll-like receptor signaling. Notably, NETs related gene aquaporin-9 (AQP9) and its associated lncRNAs exhibited significant upregulation in septic neutrophils. Functional experiments revealed AQP9 interacts with its lncRNAs to augment the formation of neutrophil NETs. In murine sepsis models, AQP9 inhibition with phloretin reduced proinflammatory cytokine production and lung damage. These findings provide crucial insights into the regulatory role of AQP9 in sepsis, unraveling its interaction with associated lncRNAs in transmitting downstream signals, holding promise in informing the development of novel therapeutic strategies aimed at ameliorating the debilitating effects of sepsis.

Inhibition of aquaporin-9 ameliorates severe acute pancreatitis and associated lung injury by NLRP3 and Nrf2/HO-1 pathways.

Inflammation, apoptosis and oxidative stress play crucial roles in the deterioration of severe acute pancreatitis-associated acute respiratory distress syndrome (SAP-ARDS). Unfortunately, despite a high mortality rate of 45 %[1], there are limited treatment options available for ARDS outside of last resort options such as mechanical ventilation and extracorporeal support strategies[2]. This study investigated the potential therapeutic role and mechanisms of AQP9 inhibitor RG100204 in two animal models of severe acute pancreatitis, inducing acute respiratory distress syndrome: 1) a sodium-taurocholate induced rat model, and 2) and Cerulein and lipopolysaccharide induced mouse model. RG100204 treatment led to a profound reduction in inflammatory cytokine expression in pancreatic, and lung tissue, in both models. In addition, infiltration of CD68 + and CD11b + cells into these tissues were reduced in RG100204 treated SAP animals, and edema and SAP associated tissue damage were improved. Moreover, we demonstrate that RG100204 reduced apoptosis in the lungs of rat SAP animals, and reduces NF-κB signaling, NLRP3, expression, while profoundly increasing the Nrf2-dependent anti oxidative stress response. We conclude that AQP9 inhibition is a promising strategy for the treatment of pancreatitis and its systemic complications, such as ARDS.

Regulatory factor for AQP9 phosphorylation and the effect on As intake in mammal cells / 中国药学杂志

OBJECTIVE: To elucidate the regulation of p38 and PKC for water channel protein AQP9 and the effect on As intake in lour kinds of mammal cells, and to investigate the regulation mechanism of AOP9 phosphorylation. METHODS: p38, PKC protein and phosphorylation levels were analyzed by Western blotting, and phosphorylation level of AQP9 was detected by immuno-precipitation. Intracellular arsenic content was determined by inductively coupled plasma mass spectrometry (ICP-MS). Experimental data were analysed by SPSS statistical software. RESULTS: p38 protein and phosphorylation levels increased significantly with time in four kinds of cells treated with NaAsO2, while no significant change had been observed in PKC protein and phosphorylation levels. AQP9 phosphorylation level was inhibited in L-02 cells when p38 activity was inhibited, and As accumulation also decreased significantly in L-02 cells. CONCLUSION: AQP9 phosphorylation has effect on As intake and rate. But the regulated mechanism may be different in different cells. p38 kinase attends partly AQP9 phosphorylation in liver normal cells L-02, PKC has no effect on AQP9 phosphorylation in all kinds cells used in this paper.

Relationship between AQP9 expression and formation of ischemic cerebral edema in the rats / 重庆医科大学学报

Objective:To study the role of AQP9 and its mRNA expression in the formation of ischemic cerebral edema in the rats.Methods:MCAO models were established by occluding unilateral middle cerebral artery(MCA) of the rats with the suture method.The morphological changes were observed with HE stain and transmission electron microscope(TEM).Brain water content(BWC) was measured by using wet-dry weighing method.The expression of AQP9 and its mRNA in the edema brain tissue were detected with in situ hybrilization(ISH) and immunohistochemistry(IHC).Results:The space around the neurons and perivascular space became larger.Some neurons showed necrosis phenotype,and the number of the neurogliocyte increased.The expression of AQP9 and its mRNA were up-regulated in subfornical organ(SFO)、choroid plexes、brain cortex、supraoptic nuclei、hippocampus and other regions,and reached its peak at 48~72h after MCAO.The brain water content(BWC) in ischemic cerebral tissue reached its peak at 72h.Conclusions:the expression of AQP9 and its mRNA were up-regulated following the brain edema.The results imply that AQP9 might play an important role in the formation of ischemic cerebral edema.

Expression and role of AQP9 in models of cultured steatosis hepatocytes / 重庆医科大学学报

Objective:To explore the expression and role of AQP9 in the models of cultured steatosis hepatocytes.Methods:Steatosis models of hepatocytes was established by adding oleic acid to the growing L-02 cell strain.The expression of AQP9 mRNA was measured with RT–PCR and the protein expression of AQP9 were measured by Western blotting.Lipid droplets in the hepatocytes were observed by oil red staining and the contents of triglyceride,FFA and glycerol in hepatocytes were measured with analyzed kit.Results:Through oil red staining.a few lipid droplets were observed at 24h and steatosis hepatocyte increased greatly at 72h.Triglyceride,FFA and glycerol contents in hepatocytes of model groups also increased,as compared with the control group(P