Zun-Ji Ke

Background: Alzheimer's disease (AD) is a neurodegenerative disease with major symptoms including memory and learning deficits. Neuroinflammation associated with reactive microglia promotes AD progression. These reactive microglia secrete prostaglandins, which are synthesized through the enzymatic activity of cyclooxygenase (COX)-1 and COX-2. Here, we aimed to elucidate the specific mechanisms of COX1 in AD pathogenesis and its interactions with neuroinflammatory processes. Methods: We conducted backcrossing between COX-1 knockout (KO) and 5 × FAD mice to evaluate the effect of COX-1 deficiency on neuroinflammation. In addition, single-cell sequencing and microarray datasets from public databases and ingenuity pathway analysis in vitro were employed to explore gene expression profiles in the brains of AD mice. Results: We identified a significant upregulation of COX-1 in 5 × FAD mice, with expression specifically localized to microglia in an age-dependent manner. Additionally, COX-1 KO alleviated neuroinflammation and accumulation of Aβ plaques, subsequently improving cognitive behavior in 5 × FAD mice. Moreover, microglia exhibited an amoeboid morphology in 5 × FAD mice, whereas in age-matched 5 × FAD/COX-1 KO mice, microglia had a ramified appearance. Additionally, our study demonstrated a pharmacological approach that inhibits the prostaglandin E2 (PGE2)/EP2 receptors via inhibition of the cAMP-PKA-NFκB-p65 pathway and NLRP3 inflammasome activation, producing similar beneficial effects as observed in COX-1 KO mice. Conclusion: Our findings indicate that targeting the COX-1/PGE2/EP2 signaling pathway may alleviate neuroinflammation and impede AD progression. Moreover, the EP2 receptor presents a promising pharmacological target for mitigating the pathological effects associated with COX-1 activity in AD patients.

Background:Neuroinflammation is one of the most important contributing factors for the pathogenesis of Alzheimer’s disease (AD). Cyclooxygenase-1 (COX-1) is distinctly expressed in microglia and involved in microglia activation and neuroinflammation in the AD. However, the molecular mechanisms by which COX-1 regulated microglia activation and participated in AD progression remains unclear. This study was designed to investigate the cellular and molecular mechanisms underlying COX-1 regulation of neuroinflammation.Methods:C57BL/6J, 5×FAD and 5×FAD/COX-1 knockout (KO) mice of different ages (e.g. 3-month-old, 6-month-old, 9-month-old) were used. Motor function and cognitive ability were evaluated using the open field test, novel-object recognition test and Morris water maze tests. The deposition of amyloid beta (Aβ) was examined by Thioflavin-S fluorescence, and neuroinflammation was investigated by immunohistochemistry, immunofluorescence and immunoblotting.Results:Konock out (KO) of COX-1 improved cognitive impairment and motor deficits, and reduced the accumulation of Aβ plaques in the cerebral cortex and hippocampus. COX-1 KO promoted microglia transition from M1 to M2 status, and reduced NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome. This was mediated by the inhibition of prostaglandin E₂(PGE₂)/EP2 pathway and cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)-nuclear factor-κB (NFκB) p65 axis.Conclusions:COX-1 may contribute to the impairment of clearance Aβ and exacerbation of neuroinflammation which led to cognitive deficits in 5×FAD transgenic mice. The effects of COX-1 were mediated through PGE₂/EP2 pathway which activated cAMP-PKA-NFκB p65 axis and NLRP3 inflammasome. The results suggest that the inhibition of COX-1 may be a potential pharmacological approach for the treatment of AD.

The liver is the most common site for colorectal cancer (CRC)–associated metastasis. There remain unsatisfactory medications in liver metastasis given the incomplete understanding of pathogenic mechanisms. Herein, with an orthotopic implantation model fed either regular or high-fat diets (HFD), more liver metastases were associated with an expansion of conjugated bile acids (BAs), particularly taurocholic acid (TCA) in the liver, and an increased gene expression of Na⁺–taurocholate cotransporting polypeptide (NTCP). Such hepatic BA change was more apparently shown in the HFD group. In the same model, TCA was proven to promote liver metastases and induce a tumor-favorable microenvironment in the liver, characterizing a high level of fibroblast activation and increased proportions of myeloid-derived immune cells. Hepatic stellate cells, a liver-residing source of fibroblasts, were dose-dependently activated by TCA, and their conditioned medium significantly enhanced the migration capability of CRC cells. Blocking hepatic BA uptake with NTCP neutralized antibody can effectively repress TCA–triggered liver metastases, with an evident suppression of tumor microenvironment niche formation. This study points to a new BA–driven mechanism of CRC–associated liver metastases, suggesting that a reduction of TCA overexposure by limiting liver uptake is a potential therapeutic option for CRC—associated liver metastasis.

Most basal-like breast cancers (BLBCs) are triple-negative breast cancers (TNBCs), which is associated with high malignancy, high rate of recurrence and distant metastasis, and poor prognosis among all types of breast cancer. However, there are currently no effective therapies for BLBC. Furthermore, chemoresistance limits the therapeutic options for BLBC treatment. In this study, we screen out protein activator of the interferon-induced protein kinase (PACT) as an essential gene in BLBC metastasis. We find that high PACT expression level was associated with poor prognosis among BLBC patients. In vivo and in vitro investigations indicated that PACT could regulate BLBC metastasis by interacting with SUMO-conjugating enzyme Ubc9 to stimulate the SUMOylation and thus consequently the activation of Rac1. BLBC patients receiving chemotherapy presents poorer prognosis with PACT high expression, and PACT disruption sensitizes experimental mammary tumor metastases to chemotherapy, thus providing insights to consider PACT as a potential therapeutic target to overcome acquired chemoresistance in BLBC.

Chronic pain is highly prevalent. Individuals with cognitive disorders such as Alzheimer disease are a susceptible population in which pain is frequently difficult to diagnosis. It is still unclear whether the pathological changes in patients with Alzheimer disease will affect pain processing. Here, we leverage animal behavior, neural activity recording, optogenetics, chemogenetics, and Alzheimer disease modeling to examine the contribution of the anterior cingulate cortex (ACC) neurons to pain response. The 5× familial Alzheimer disease mice show alleviated mechanical allodynia which can be regained by the genetic activation of ACC excitatory neurons. Furthermore, the lower peak neuronal excitation, delayed response initiation, as well as the dendritic spine reduction of ACC pyramidal neurons in 5×familial Alzheimer disease mice can be mimicked by Rac1 or actin polymerization inhibitor in wild-type (WT) mice. These findings indicate that abnormal of pain sensitivity in Alzheimer disease modeling mice is closely related to the variation of neuronal activity and dendritic spine loss in ACC pyramidal neurons, suggesting the crucial role of dendritic spine density in pain processing.

Natural killer (NK) cells, a key member of innate lymphocytes, are a promising immunotherapeutic target for ischemic stroke. Astragaloside IV (ASIV) is isolated fromAstragalus mongholicus Bunge(Fabaceae), a herbal medicine possessing immunomodulatory ability. This study investigated the effect of ASIV on NK cells during the acute stage of brain ischemic injury in a mouse model of middle cerebral artery occlusion (MCAO). MCAO mice treated with ASIV had better functional outcomes, smaller brain infarction and less NK cell brain infiltration. NK cell depletion echoed the protective effect of ASIV. Notably, ASIV did not enhance the protective effect of NK cell depletion against brain ischemic injury. ASIV inhibited glial cell-derived CCL2-mediated chemotaxis to prevent post-ischemic NK cell brain recruitment. Meanwhile, ASIV also abrogated NK cell-mediated cytolytic killing of neurons subjected to oxygen-glucose deprivation and suppressed NK cell-derived IFN-γ and NKG2D expression in the ischemic brain. The inhibitory effect of ASIV on NK cell brain infiltration and activation was mimicked by cryptotanshinone, a STAT3 inhibitor. There was no additive effect when ASIV and cryptotanshinone were used together. In conclusion, ASIV inhibits post-ischemic brain infiltration and activation of NK cells through STAT3 suppression, and this inhibitory effect of ASIV on NK cells plays a key role in its protection against acute ischemic brain injury. Our findings suggest that ASIV is a promising therapeutic candidate in NK cell-based immunotherapy for the treatment of acute ischemic stroke and pave the way for potential clinical trials.

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandin (PG) formation by targeting cyclooxygenase (COX) 1 and 2. Long-term use of NSAIDs that selectively inhibit COX2 increases the risk for thrombotic events, cardiac failure, and hypertension. However, the underlying mechanisms remain unclear. In this study, COX1- and COX2-deficient rats were created via Cas9/RNA-mediated gene targeting. DNA genotyping and Western blot analysis confirmed successful generation of COX1^−/−and COX2^−/− rats. Adult COX1^−/− rats grew normally, while more than 70% of COX2^−/− rats after wean died within 2 months. Echocardiography showed markedly reduced left ventricular ejection fraction and fractional shortening in adult COX2^−/− rats compared to those in wildtype (WT) controls. Histological analysis revealed accumulation of inflammatory cells and severe interstitial and perivascular fibrosis in COX2^−/− cardiac tissues. Moreover, cardiac ATP and acetyl-CoA production was dramatically decreased in COX2^−/− rats. Consistently, the expression of genes related to mitochondrial oxidation, such as those that encode for subunits of pyruvate dehydrogenase complex and acyl CoA dehydrogenases, were downregulated, while glycolytic hexokinase 1 (HK1) was upregulated in COX2^−/− heart tissues. These observations indicate that COX2-deficient rats developed spontaneously heart failure, likely as a result of dysregulated cardiac energy metabolism.

Ketamine is a widely used intravenous anesthetic; however, basic and clinical studies have demonstrated that prolonged exposure can cause irreversible injury to the immature human brain. Yes‑associated protein (YAP) is the main effector of the Hippo signaling pathway, which serves an important role in regulating tissue homeostasis and organ size during development. However, whether YAP mediates ketamine‑induced apoptosis is not completely understood. Based on the functions of YAP during apoptosis resistance and cell self‑renewal regulation, the present study hypothesized that YAP serves a role during ketamine‑induced apoptosis. An in vitro model was utilized to investigate the effects of ketamine on neurotoxicity and to further investigate the role of YAP in ketamine‑induced apoptosis using techniques including CCK‑8 assay, flow cytometry and western blotting. The present study assessed the effects of YAP overexpression and knockdown on the expression of typical apoptotic markers in SH‑SY5Y cells. Ketamine induced apoptosis in a dose‑dependent manner, which was regulated by YAP. Following YAP overexpression, ketamine‑treated SH‑SY5Y cells displayed increased activity and viability, whereas expression levels of the apoptotic markers were decreased compared with the negative control group. By contrast, ketamine‑induced apoptosis was enhanced following YAP knockdown. Collectively, the results of the present study indicated that YAP may serve an important role during ketamine‑induced neurotoxicity, and alterations to YAP signaling may counteract ketamine‑induced apoptosis. The neuroprotective effect of YAP activation may serve as a novel pharmacological target for the treatment of ketamine‑induced neurotoxicity via neurogenesis normalization.