Phenylbutyrate Research Articles

4-PBA exerts brain-protective effects against sepsis-associated encephalopathy in a mouse model of sepsis

BackgroundNeuroinflammation assumes a pivotal role in both the etiological underpinnings and the dynamic progression of sepsis-associated encephalopathy (SAE). The occurrence of cognitive deficits with SAE is associated with neuroinflammation. 4-phenyl butyrate (4-PBA) may control inflammation by inhibiting endoplasmic reticulum stress (ERS). The primary objective of this investigation is to scrutinize the effectiveness of 4-PBA in mitigating neuroinflammation induced by lipopolysaccharides (LPS) and its consequent impact on cognitive function decline. MethodsLPS-injected mice with SAE and LPS-treated BV2 cell were established to serve as experimental paradigms, both contributing to the investigative framework of the study. Cognitive functions were assessed by behavioral tests. Hippocampal neuronal damage was assessed using Golgi staining and Nissl staining. Quantitative PCR assay and immunofluorescence were used to analyze neuroinflammation. Mitochondrial function was examined using transmission electron microscopy. Protein expression analysis was conducted through the application of western blotting methodology, serving as the investigative approach to elucidate molecular signatures in the experimental framework. Endoplasmic reticulum and mitochondrial calcium flow were detected using flow cytometry. To delve deeper into the mechanistic intricacies, the administration of 4μ8c was employed to selectively impede the IRE1α/Xbp1s pathway, constituting a strategic intervention aimed at elucidating underlying regulatory processes. ResultExpression levels of ERS-related proteins exhibited a significant upregulation in hippocampal tissues of LPS-treated mice when compared to wild-type (WT) counterparts. The administration of 4-PBA notably ameliorated memory deficits in LPS-treated mice. Furthermore, 4-PBA treatment was found to alleviate oxidative stress and neuroinflammation. Mechanistically, the IRE1α/Xbp1s-Ca2+ signaling pathway played a crucial role in mediating the beneficial effects of mitigating oxidative stress and maintaining mitochondrial calcium homeostasis, with inhibition of the IRE-related pathway displaying opposing effects. ConclusionOur results suggest that administration of 4-PBA treatment significantly attenuates ERS, alleviates cognitive decline, reduces inflammatory damage, and restores mitochondrial dynamics via the IRE1α/Xbp1s-Ca2+-associated pathway, which provides a new potential therapeutic approach to SAE.

Suppressing Endoplasmic Reticulum Stress Alleviates LPS-Induced Acute Lung Injury via Inhibiting Inflammation and Ferroptosis.

Acute lung injury (ALI) is a life-threatening clinical disorder with high mortality rate. Ferroptosis is a new type of programmed cell death with lipid peroxidation and iron ion overloading as the main characteristics. Endoplasmic reticulum (ER) stress and ferroptosis play pivotal roles in the pathogenesis of ALI. The study aimed to investigate the underlying relationship between ER stress and ferroptosis in ALI. The ER stress inhibitor 4-phenylbutyric acid (4-PBA) alleviated LPS-induced inflammation, and decreased IL-1β, IL-6, and TNF-α levels in BALF and lungs. The increased MDA and decreased GSH induced by LPS were partially reversed by 4-PBA, which also inhibited the expressions of ferroptosis-related protein ACSL4, COX-2, and FTH1. TEM further confirmed the ferroptosis within airway epithelia cells was ameliorated by 4-PBA. Moreover, 4-PBA reduced the production of ROS and lipid ROS in LPS-exposed BEAS-2B cells in a concentration-dependent way. Meanwhile, 4-PBA mitigated LPS-induced cell apoptosis in vivo and in vitro. Mechanistically, the MAPK signaling pathway activated by LPS was downregulated by 4-PBA. Collectively, these findings suggested that 4-PBA protected against ALI by inhibiting inflammation and ferroptosis through downregulating ER stress, thus providing a potential intervention for ALI and revealing the possible interaction between ER stress and ferroptosis in ALI.

Amlodipine inhibits the proliferation and migration of esophageal carcinoma cells through the induction of endoplasmic reticulum stress.

L-type calcium channels are the only protein channels sensitive to calcium channel blockers, and are expressed in various cancer types. The Cancer Genome Atlas database shows that the mRNA levels of multiple L-type calcium channel subunits in esophageal squamous cell carcinoma tumor tissue are significantly higher than those in normal esophageal epithelial tissue. Therefore, we hypothesized that amlodipine, a long-acting dihydropyridine L-type calcium channel blocker, may inhibit the occurrence and development of esophageal cancer (EC). To investigate the inhibitory effects of amlodipine on EC through endoplasmic reticulum (ER) stress. Cav1.3 protein expression levels in 50 pairs of EC tissues and corresponding paracancerous tissues were examined. Subsequently, the inhibitory effects of amlodipine on proliferation and migration of EC cells in vitro were detected using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and Transwell assays. In vivo experiments were performed using murine xenograft model. To elucidate the underlying mechanisms, in vitro cell studies were performed to confirm that ER stress plays a role in inhibition proliferation and migration of EC cells treated with amlodipine. The expression level of Cav1.3 in esophageal carcinoma was 1.6 times higher than that in paracancerous tissues. Amlodipine treatment decreased the viability of esophageal carcinoma cells in a dose- and time-dependent manner. In vivo animal experiments also clearly indicated that amlodipine inhibited the growth of EC tumors in mice. Additionally, amlodipine reduces the migration of tumor cells by inhibiting epithelial-mesenchymal transition (EMT). Mechanistic studies have demonstrated that amlodipine induces ER stress-mediated apoptosis and suppresses EMT. Moreover, amlodipine-induced autophagy was characterized by an increase in autophagy lysosomes and the accumulation of light chain 3B protein. The combination of amlodipine with the ER stress inhibitor 4-phenylbutyric acid further confirmed the role of the ER stress response in amlodipine-induced apoptosis, EMT, and autophagy. Furthermore, blocking autophagy increases the ratio of apoptosis and migration. Collectively, we demonstrate for the first time that amlodipine promotes apoptosis, induces autophagy, and inhibits migration through ER stress, thereby exerting anti-tumor effects in EC.

An Alternative Pathway for the Synthesis of Glycerol Phenylbutyrate

AbstractHyperammonemia is a life‐threatening condition which can affect patients at any age. In pediatric patients, hyperammonemia can be caused by various acquired or inherited disorders such as urea cycle deficiencies or organic acidemias. Glycerol phenylbutyrate (GPB) is an orphan drug used in the treatment of hyperammonemia. GPB is a triglyceride composed of three phenylbutyric acid (PBA) molecules esterified to a glycerol molecule, which is synthesized through the acyl chloride route using thionyl chloride as an acylating agent. In this work we have developed an alternative synthesis method to obtain GPB directly under ambient conditions and avoiding the use of chlorinated solvents. Moreover, the use of carbodiimides as coupling agents, instead of thionyl chloride, allowed the conversion to the GPB in higher yields and with higher purity, without the need for column purification. We present a methodology that allows the production of GPB in a simple, efficient and environmentally and human health friendly way.

Methylparaben induces hepatic glycolipid metabolism disorder by activating the IRE1α-XBP1 signaling pathway in male mice

Methylparaben (MP), a preservative widely used in daily supplies, exists in both the environment and the human body. However, the potential health risks posed by MP remain unclear. This study aimed to unravel the mechanisms by which MP disrupts glucose and lipid homeostasis. For this, we administered MP to mice and observed changes in glucose and lipid metabolism. MP exposure led to hyperglycemia, hyperlipidemia, visceral organ injury, and hepatic lipid accumulation. RNA sequencing results from mice livers indicated a close association between MP exposure and endoplasmic reticulum (ER) stress, inflammatory response, and glucose and lipid homeostasis. Western blotting and quantitative reverse transcription–polymerase chain reaction revealed that MP activated ER stress, particularly the inositol-requiring enzyme 1 (IRE1)/X-box binding protein 1 (XBP1) pathway, which further promoted the activation of the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. The activation of these pathways phosphorylated insulin receptor substrate-1 (IRS1) (ser 307), resulting in decreased phosphorylation of protein kinase B (Akt) (ser 473), leading to insulin resistance. Additionally, MP exposure promoted lipogenesis through ER stress. To explore potential remedies, we administered the ER stress inhibitor 4-phenylbutyric acid (4-PBA) and the IRE1α-XBP1 pathway inhibitor toyocamycin to mice, both of which protected against metabolic disorders and organ injury caused by MP. These findings suggest that MP induces disruptions in glucose and lipid metabolism through ER stress, primarily through the IRE1α-XBP1 pathway.

PBA alleviates cadmium-induced mouse spermatogonia apoptosis by suppressing endoplasmic reticulum stress

ObjectiveEndoplasmic reticulum (ER) stress mediates Cd-caused germ cell apoptosis in testis. The effects of 4-phenylbutyric acid (PBA), a classical chaperone, were investigated on Cd-induced apoptosis in mouse GC-1 spermatogonia cells. MethodsThe cells were pretreated with PBA before Cd exposure. TUNEL and flow cytometry assays were applied to determine apoptosis. Some key biomarkers of ER stress were analyzed using RT-PCR and western blot. Resultsas expected, the apoptotic cells exposed to Cd apparently increased. The mRNA and protein expression levels of GRP78 and ATF6α, were elevated in the Cd groups. Additional experiments displayed that Cd notably increased IRE1α and JNK phosphorylation, and upregulated XBP-1 mRNA and protein expression. Moreover, p-eIF2α and CHOP expressions were clearly elevated in the Cd groups. Interestingly, PBA almost completely inhibited ER stress and protected spermatogonia against apoptosis induced by Cd. ConclusionPBA alleviated Cd-induced ER stress and spermatogonia apoptosis, and may have the therapeutic role in Cd-induced male reproductive toxicity.

Cholesterol-induced HRD1 reduction accelerates vascular smooth muscle cell senescence via stimulation of endoplasmic reticulum stress-induced reactive oxygen species

Senescence of vascular smooth muscle cells (VSMCs) is a key contributor to plaque vulnerability in atherosclerosis (AS), which is affected by endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production. However, the crosstalk between ER stress and ROS production in the pathogenesis of VSMC senescence remains to be elucidated. ER-associated degradation (ERAD) is a complex process that clears unfolded or misfolded proteins to maintain ER homeostasis. HRD1 is the major E3 ligase in mammalian ERAD machineries that catalyzes ubiquitin conjugation to the unfolded or misfolded proteins for degradation. Our results showed that HRD1 protein levels were reduced in human AS plaques and aortic roots from ApoE−/− mice fed with high-fat diet (HFD), along with the increased ER stress response. Exposure to cholesterol in VSMCs activated inflammatory signaling and induced senescence, while reduced HRD1 protein expression. CRISPR Cas9-mediated HRD1 knockout (KO) exacerbated cholesterol- and thapsigargin-induced cell senescence. Inhibiting ER stress with 4-PBA (4-Phenylbutyric acid) partially reversed the ROS production and cell senescence induced by HRD1 deficiency in VSMCs, suggesting that ER stress alone could be sufficient to induce ROS production and senescence in VSMCs. Besides, HRD1 deficiency led to mitochondrial dysfunction, and reducing ROS production from impaired mitochondria partly reversed HRD1 deficiency-induced cell senescence. Finally, we showed that the overexpression of HDR1 reversed cholesterol-induced ER stress, ROS production, and cellular senescence in VSMCs. Our findings indicate that HRD1 protects against senescence by maintaining ER homeostasis and mitochondrial functionality. Thus, targeting HRD1 function may help to mitigate VSMC senescence and prevent vascular aging related diseases. Trial registrationA real-world study based on the discussion of primary and secondary prevention strategies for coronary heart disease, URL:https://www.clinicaltrials.gov, the trial registration number is [2022]-02–121-01.

Pridopidine subtly ameliorates motor skills in a mouse model for vanishing white matter.

The leukodystrophy vanishing white matter (VWM) is characterized by chronic and episodic acute neurological deterioration. Curative treatment is presently unavailable. Pathogenic variants in the genes encoding eukaryotic initiation factor 2B (eIF2B) cause VWM and deregulate the integrated stress response (ISR). Previous studies in VWM mouse models showed that several ISR-targeting compounds ameliorate clinical and neuropathological disease hallmarks. It is unclear which ISR components are suitable therapeutic targets. In this study, effects of 4-phenylbutyric acid, tauroursodeoxycholic acid, or pridopidine (PDPD), with ISR targets upstream or downstream of eIF2B, were assessed in VWM mice. In addition, it was found that the composite ataxia score represented motor decline of VWM mice more accurately than the previously used neuroscore. 4-phenylbutyric acid and tauroursodeoxycholic acid did not improve VWM disease hallmarks, whereas PDPD had subtle beneficial effects on motor skills. PDPD alone does not suffice as treatment in VWM mice but may be considered for combination therapy. Also, treatments aimed at ISR components upstream of eIF2B do not improve chronic neurological deterioration; effects on acute episodic decline remain to be investigated.

Sestrin2 ameliorates diabetic retinopathy by regulating autophagy and ferroptosis.

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes. The aim of this study was to explore the effect of Sestrin2 on DR through the regulation of autophagy and ferroptosis levels and its mechanism. In vitro and in vivo DR models were established by high glucose (HG) and streptozotocin (STZ) induction of ARPE-19 human retinal pigment epithelial cells and C57BL/6 mice, respectively. In this study, we demonstrated that after HG treatment, the activity of ARPE-19 cells was decreased, the apoptosis rate was increased, endoplasmic reticulum (ER) stress was activated, autophagy levels were decreased, and ferroptosis levels were increased. Overexpression of Sestrin2 enhanced cell viability, reduced apoptosis and ferroptosis, and enhanced autophagy. However, the effect of overexpression of Sestrin2 was attenuated after the addition of the STAT3 phosphorylation activator Colivelin TFA (C-TFA), the mTOR pathway activator MHY1485 or the autophagy inhibitor 3-methyladenine (3-MA). In addition, the effect of Sestrin2 knockdown on cells was opposite to the effect of overexpression of Sestrin2, while the effect of Sestrin2 knockdown was attenuated after treatment with the ER stress inhibitor 4-phenylbutyric acid (4-PBA). Animal experiments also confirmed the results of cell experiments and attenuated the effects of overexpression of Sestrin2 after injection of the ferroptosis activators erastin or 3-MA. Our study revealed that Sestrin2 inhibits ferroptosis by inhibiting STAT3 phosphorylation and ER stress and promoting autophagy levels, thereby alleviating DR.

Anticancer activity of liposomal formulation co-encapsulated with coumarin and phenyl butyric acid

Anticancer treatments have poor pharmacokinetics, high toxicity to normal cells, and low bioavailability. As nanotechnology has advanced to a new level, many researchers have been motivated to develop a safer and more effective medication delivery method for the treatment of cancer. Nowadays, about 80% of the anticancer medications that have been approved recently are made from natural substances. This study aims to formulate liposomes loaded with coumarin (COM) and 4-phenylbutyric acid (PBA) and evaluate their antitumor effect in vitro. The liposomes were characterized using the dynamic light scattering instrument to determine their size, polydispersity, and charge. The formulated liposomes exhibited a particle size within the desired range of 100– 200 nm, with low polydispersity and suitable charge. Stability tests showed excellent stability of the liposomal formulations over 10 days in terms of size, charge, and polydispersity. High performance liquid chromatography analysis confirmed the successful encapsulation of COM and PBA within the liposomes, with high encapsulation efficiencies observed of 53%–25% for Lipo-PBA and Lipo-COM, respectively. Loading efficiency (LO%) was found to be 9%–5% for Lipo-PBA and Lipo-COM, respectively, which means the drugs were efficiently loaded within the liposome. In vitro cell viability studies demonstrated that the liposomes loaded with both COM and PBA exhibited the most effective inhibition on MDA-MB-231 breast cancer cells (30%) and A549 lung cancer cells (45%), while Lipo-COM showed potent inhibition on HT29 colorectal cancer cells (40%). Encapsulation of the drugs inside liposomes enhanced their cytotoxicity, potentially due to improved penetration into tumor cells. The findings suggest that the formulated liposomes have the potential for future clinical applications with high selectivity toward cancer cells.

Curcumin affects apoptosis of colorectal cancer cells through ATF6-mediated endoplasmic reticulum stress.

Colorectal cancer (CRC) is the main cause of cancer-associated death. Herein, we treated SW620 and HT-29 CRC cells with different curcumin concentrations, followed by treatment with the half maximal inhibitory concentration (IC50) curcumin/endoplasmic reticulum stress (ERS) inhibitor 4-phenyl butyric acid (4-PBA)/activating transcription factor 6 (ATF6) interference plasmid (si-ATF6). We detected cell proliferation/apoptosis, ATF6 cellular localization/nuclear translocation, ion concentration, ATF6 protein/apoptotic protein (Bax/Bcl-2/Cleaved Caspase-3) levels, and ERS-related proteins (glucose-regulated protein 78 [Grp78]/C/EBP homologous protein [CHOP]). We discovered inhibited cell proliferation/growth, enhanced cell apoptosis/(Bax/Bcl-2) ratio/Cleaved Caspase-3 levels/Ca2+ concentration in the cytoplasm/ERS-related protein (Grp78/CHOP) levels, and activated ERS following treatment with IC50 curcumin. 4-PBA partially reversed the inhibitory effect of curcumin on SW620 cells by restraining ERS. Curcumin stimulated ATF6 expression and its nuclear translocation to activate ERS. ATF6 silencing partly annulled the inhibitory effect of curcumin on SW620 cells. Our study explored the molecular mechanism of curcumin affecting CRC cell apoptosis through ATF6.

Protective Effects and Mechanisms of Inhibiting Endoplasmic Reticulum Stress on Cold Seawater Immersion Combined with Hemorrhagic Shock.

Cold seawater immersion aggravates hemorrhagic shock-induced homeostasis imbalance and organ dysfunction, leading to increased mortality. Previous studies have shown that treatments targeting oxidative stress and mitochondrial dysfunction have limited efficacy for cold seawater immersion combined with hemorrhagic shock (SIHS). Thus, the mechanisms responsible for SIHS need further investigation. Data from the hemorrhagic shock transcriptome and cold seawater immersion targets used for bioinformatics analysis revealed the involvement of endoplasmic reticulum stress (ERS) in SIHS occurrence and progression. Based on these findings, the effects and possible mechanism of inhibiting ERS in SIHS rats were investigated. SIHS causes a lethal triad and impairment of vital organ function, leading to death. Compared to lactated Ringer's solution, the ERS inhibitor 4-phenylbutyric acid (PBA)significantly ameliorated acidosis and coagulopathy and protected vital organ function while prolonging survival and the golden treatment time. Through target screening and validation, 7 targets were identified for the ERS inhibitor PBA for the treatment of SIHS, among which S1PR1, MMP8 and CFTR may play more important roles. ERS plays a crucial role in the progression of SIHS. Inhibition of ERS caused by SIHS alleviates the lethal triad, protects organ function, and prolongs survival and the golden treatment time. The ERS inhibitor PBA may be an effective therapeutic measure for treating SIHS.

SERCA2 dysfunction triggers hypertension by interrupting mitochondrial homeostasis and provoking oxidative stress

Background and aimSarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) is critical in maintaining Ca2+ homeostasis. The cysteine 674 (C674) is the key redox regulatory cysteine in regulating SERCA2 activity, which is irreversibly oxidized in the renal cortex of hypertensive mice. We have reported that the substitution of C674 by serine causes SERCA2 dysfunction and increases blood pressure by induction of endoplasmic reticulum stress (ERS). This study is to explore whether the dysfunction of SERCA2 causes hypertension by interrupting mitochondrial homeostasis and inducing oxidative stress. Methods & resultsWe used heterozygous SERCA2 C674S gene mutation knock-in (SKI) mice, where one copy of C674 was substituted by serine to represent partial C674 oxidation. In renal proximal tubule (RPT) cells, the substitution of C674 by serine decreased mitochondrial Ca2+ content, increased mitochondrial membrane potential, ATP content, and reactive oxygen species (ROS), which could be reversed by ERS inhibitor 4-phenylbutyric acid or SERCA2 agonist CDN1163. In SKI RPT cells, the redox modulator Tempol alleviated oxidative stress, downregulated the protein expression of ERS markers and soluble epoxide hydrolase, upregulated the protein expression of dopamine D1 receptor, and reduced Na+/K+- ATPase activity. In SKI mice, SERCA2 agonists CDN1163 and [6]-Gingerol, or the redox modulator Tempol increased urine output and lowered blood pressure. ConclusionThe irreversible oxidation of C674 is not only an indicator of increased ROS, but also further inducing oxidative stress to cause hypertension. Activation of SERCA2 or inhibition of oxidative stress is beneficial to alleviate hypertension caused by SERCA2 dysfunction.

C/EBPα alleviates hepatic ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress via HDAC1-mediated deacetylation of ATF4.

Hepatic ischemia-reperfusion (IR) injury is a complex systemic process causing a series clinical problem. C/EBPα is a key transcription factor for hepatocyte function, but its role and mechanism in regulating hepatic IR injury are largely unknown. Occluding portal vein and hepatic artery was used to establish a mouse model of hepatic IR injury. C/EBPα expression was decreased in IR-injured liver compared with the sham, accompanied by increased contents of serum alanine transaminase(ALT), aspartate transaminase(AST),high mobility group box-1, and proportion of hepatic cells. Oxygen and glucose deprivation/recovery (OGD/R) was used to establish a cellular hepatic IR model in WRL-68 hepatocytes in vitro, and C/EBPα was overexpressed in the hepatocytes to evaluate its effect on hepatic IR injury. OGD/R promoted oxidative stress, cell apoptosis and endoplasmic reticulum (ER) stress in hepatocytes, which was reversed by C/EBPα overexpression. Then, we found that C/EBPα promoted histone deacetylase 1 (HDAC1) transcription through binding to HDAC1 promoter. Moreover, HDAC1 deacetylated the activating transcription factor 4 (ATF4), a key positive regulator of ERstress. Trichostatin-A(an HDAC inhibitor) or ATF4 overexpression reversed the improvement of C/EBPα on OGD/R-induced ER stress and hepatocyte dysfunction. 4-Phenylbutyric acid(an endoplasmic reticulum stress inhibitor) also reversed the hepatic IR injury induced by ATF4 overexpression. Finally, lentivirus-mediated C/EBPα overexpression vector was applied to administrate hepatic IR mice, and the results showed that C/EBPα overexpression ameliorated IR-inducedhepatic injury, manifesting with reduced ALT/AST, oxidative stress and ER stress. Altogether, our findings suggested that C/EBPα ameliorated hepatic IR injury by inhibiting ER stress via HDAC1-mediated deacetylation of ATF4 promoter.

Nitric oxide-induced endoplasmic reticulum stress of Schistosoma japonicum inhibits the worm development in rats

Schistosomiasis, caused by Schistosoma spp., is a zoonotic parasitic disease affecting human health. Rattus norvegicus (rats) are a non-permissive host of Schistosoma, in which the worms cannot mature and cause typical egg granuloma. We previously demonstrated that inherent high levels of nitric oxide (NO), produced by inducible NO synthase (iNOS), is a key molecule in blocking the development of S. japonicum in rats. To further explore the mechanism of NO inhibiting S. japonicum development in rats, we performed S-nitrosocysteine proteomics of S. japonicum collected from infected rats and mice. The results suggested that S. japonicum in rats may have undergone endoplasmic reticulum (ER) stress. Interestingly, we found that the ER of S. japonicum in rats showed marked damage, while the ER of the worm in iNOS−/− rats and mice were relatively normal. Moreover, the expression of ER stress markers in S. japonicum from WT rats was significantly increased, compared with S. japonicum from iNOS−/− rats and mice. Using the NO donor sodium nitroprusside in vitro, we demonstrated that NO could induce ER stress in S. japonicum in a dose-dependent manner, and the NO-induced ER stress in S. japonicum could be inhibited by ER stress inhibitor 4-Phenyl butyric acid. We further verified that inhibiting ER stress of S. japonicum in rats promoted parasite development and survival. Furthermore, we demonstrated that NO-induced ER stress of S. japonicum was related to the efflux of Ca2+ from ER and the impairment of mitochondrial function. Collectively, these findings show that high levels of NO in rats could induce ER stress in S. japonicum by promoting the efflux of Ca2+ from ER and damaging the mitochondrial function, which block the worm development. Thus, this study further clarifies the mechanism of anti-schistosome in rats and provides potential strategies for drug development against schistosomiasis and other parasitosis.

Impact of endoplasmic reticulum stress on chondrocyte apoptosis in rat model of DDH.

Developmental dysplasia of the hip (DDH) is a developmental disorder characterized by acetabular dysplasia leading to early osteoarthritis. This study examines the role of endoplasmic reticulum stress (ERS) in chondrocyte apoptosis and cartilage degeneration within a DDH model. In the rat model of DDH, created using a swaddling technique, significant deformities in the femoral head and acetabulum were observed, alongside an upregulation of matrix metalloproteinase-13 in acetabular cartilage. We also noted increased levels of apoptosis and ERS-related factors in the acetabular cartilage of DDH models. Additionally, rat chondrocytes exposed to high-magnitude cyclic tensile strain (CTS, 1 Hz, 10% equibiaxial strain) in vitro exhibited elevated ERS and increased apoptosis. Importantly, treatment with the ERS inhibitor 4-phenylbutyric acid effectively suppressed apoptosis induced by CTS in chondrocytes. Our findings suggest that ERS contributes to the upregulation of apoptosis-related factors in chondrocytes within the DDH model, indicating the potential of ERS modulation as a therapeutic approach for DDH-related cartilage degeneration.

Dibromoacetonitrile induced autophagy by mediating the PERK signalling pathway and ROS interaction in HT22 cell

Dibromoacetonitrile (DBAN) is a high-risk haloacetonitrile (HAN) generated as a byproduct of chloramine disinfection in drinking water. DBAN-induced neurotoxicity in mouse hippocampal neuronal cells (HT22) and mammals was observed to be related to reactive oxygen species (ROS). ROS, endoplasmic reticulum stress (ERS) and autophagy play crucial roles in regulating a variety of cellular processes. However, whether ERS and autophagy are associated with HAN-responsive apoptosis remains unclear. This study indicated that DBAN (10 μM, 24 h) activated the ERS protein kinase like endoplasmic reticulum kinase (PERK) signaling pathway. The ERS inhibitor 4-phenylbutyric acid (4-PBA) reversed DBAN-inhibited cell viability and alleviated DBAN-induced apoptosis in HT22 cell, indicating that activation of the ERS PERK pathway mediates DBAN induced cytotoxicity. Moreover, DBAN activated autophagy. The autophagy inhibitor 3-methyladenine(3-MA) reversed DBAN-inhibited cell viability and alleviated DBAN-induced apoptosis in HT22 cell, suggesting that autophagy activation mediates DBAN-induced cell toxicity. Notably, the results showed that 4-PBA inhibited DBAN-activated autophagy, demonstrating that ERS–PERK promotes DBAN-induced cellular autophagy. Pretreatment with antioxidant N-acetylcysteine (NAC) inhibited the increase in ROS production and the activation of ERS, and protected cells from toxicity. Furthermore, 4-PBA pretreatment reduced the increase in ROS production, indicating that the ROS and PERK promote each other and form a positive feedback loop. ROS also promoted DBAN-induced autophagy. In summary, our findings indicate that DBAN induced autophagy by mediating the PERK signalling pathway and ROS interaction, leading to HT22 cell damage. Accordingly, targeting these pathogenic mechanisms may provide a potential target and theoretical basis for preventing and improving HAN-induced neurotoxicity.

Functional characterization of missense variants affecting the extracellular domains of ABCA1 using a fluorescence-based assay

Excess cholesterol originating from nonhepatic tissues is transported within HDL particles to the liver for metabolism and excretion. Cholesterol efflux is initiated by lipid-free or lipid-poor apolipoprotein A1 interacting with the transmembrane protein ABCA1, a key player in cholesterol homeostasis. Defective ABCA1 results in reduced serum levels of HDL cholesterol, deposition of cholesterol in arteries, and an increased risk of early onset CVD. Over 300 genetic variants in ABCA1 have been reported, many of which are associated with reduced HDL cholesterol levels. Only a few of these have been functionally characterized. In this study, we have analyzed 51 previously unclassified missense variants affecting the extracellular domains of ABCA1 using a sensitive, easy, and low-cost fluorescence-based assay. Among these, only 12 variants showed a distinct loss-of-function phenotype, asserting their direct association with severe HDL disorders. These findings emphasize the crucial role of functional characterization of genetic variants in pathogenicity assessment and precision medicine. The functional rescue of ABCA1 loss-of-function variants through proteasomal inhibition or by the use of the chemical chaperone 4-phenylbutyric acid was genotype specific. Genotype-specific responses were also observed for the ability of apolipoprotein A1 to stabilize the different ABCA1 variants. In view of personalized medicine, this could potentially form the basis for novel therapeutic strategies.

Treatment and management for children with urea cycle disorder in chronic stage.

Urea cycle disorder (UCD) is a group of inherited metabolic diseases with high disability or fatality rate, which need long-term drug treatment and diet management. Except those with Citrin deficiency or liver transplantation, all pediatric patients require lifelong low protein diet with safe levels of protein intake and adequate energy and lipids supply for their corresponding age; supplementing essential amino acids and protein-free milk are also needed if necessary. The drugs for long-term use include nitrogen scavengers (sodium benzoate, sodium phenylbutyrate, glycerol phenylbutyrate), urea cycle activation/substrate supplementation agents (N-carbamylglutamate, arginine, citrulline), etc. Liver transplantation is recommended for pediatric patients not responding to standard diet and drug treatment, and those with severe progressive liver disease and/or recurrent metabolic decompensations. Gene therapy, stem cell therapy, enzyme therapy and other novel technologies may offer options for treatment in UCD patients. The regular biochemical assessments like blood ammonia, liver function and plasma amino acid profile are needed, and physical growth, intellectual development, nutritional intake should be also evaluated for adjusting treatment in time.

4-phenyl butyric acid improves hepatic ischemia/reperfusion and affects gene expression of ABC transporter Abcc5 in rats

4-phenyl butyric acid improves hepatic ischemia/reperfusion and affects gene expression of ABC transporter Abcc5 in rats