Effect Of 4-phenylbutyric Acid Research Articles

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.

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.

The effects of 4-Phenylbutyric acid on ER stress during mouse tooth development.

Introduction: During tooth development, proper protein folding and trafficking are significant processes as newly synthesized proteins proceed to form designated tissues. Endoplasmic reticulum (ER) stress occurs inevitably in tooth development as unfolded and misfolded proteins accumulate in ER. 4-Phenylbutyric acid (4PBA) is a FDA approved drug and known as a chemical chaperone which alleviates the ER stress. Recently, several studies showed that 4PBA performs therapeutic effects in some genetic diseases due to misfolding of proteins, metabolic related-diseases and apoptosis due to ER stress. However, the roles of 4PBA during odontogenesis are not elucidated. This study revealed the effects of 4PBA during molar development in mice. Methods: We employed in vitro organ cultivation and renal transplantation methods which would mimic the permanent tooth development in an infant period of human. The in vitro cultivated tooth germs and renal calcified teeth were examined by histology and immunohistochemical analysis. Results and Discussion: Our results revealed that treatment of 4PBA altered expression patterns of enamel knot related signaling molecules, and consequently affected cellular secretion and patterned formation of dental hard tissues including dentin and enamel during tooth morphogenesis. The alteration of ER stress by 4PBA treatment during organogenesis would suggest that proper ER stress is important for pattern formation during tooth development and morphogenesis, and 4PBA as a chemical chaperone would be one of the candidate molecules for dental and hard tissue regeneration.

Amelioration of osteogenesis in iPSC-derived mesenchymal stem cells from osteogenesis imperfecta patients by endoplasmic reticulum stress inhibitor

AimOsteogenesis imperfecta (OI) is a hereditary connective tissue disorder primarily caused by mutations in COL1A1 or COL1A2, which encode type I collagen. These mutations affect the quantity and/or quality of collagen composition in bones, leading to bone fragility. Currently, there is still a lack of treatment that addresses disease-causing factors due to an insufficient understanding of the pathological mechanisms involved. Main methodsInduced pluripotent stem cells (iPSCs) were generated from OI patients with glycine substitution mutations in COL1A1 and COL1A2 and developed into mesenchymal stem cells (iPS-MSCs). OI-derived iPS-MSCs underwent in vitro osteogenic induction to study cell growth, osteogenic differentiation capacity, mRNA expression of osteogenic and unfolded protein response (UPR) markers and apoptosis. The effects of 4-phenylbutyric acid (4-PBA) were examined after treatment of OI iPS-MSCs during osteogenesis. Key findingsOI-derived iPS-MSCs exhibited decreased cell growth and impaired osteogenic differentiation and collagen expression. Expression of UPR genes was increased, which led to an increase in apoptotic cell death. 4-PBA treatment decreased apoptotic cells and reduced expression of UPR genes, including HSPA5, XBP1, ATF4, DDIT3, and ATF6. Osteogenic phenotypes, including RUNX2, SPP1, BGLAP, and IBPS expression, as well as calcium mineralization, were also improved. SignificanceMSCs differentiated from disease-specific iPSCs have utility as a disease model for identifying disease-specific treatments. In addition, the ER stress-associated UPR could be a pathogenic mechanism associated with OI. Treatment with 4-PBA alleviated OI pathogenesis by attenuating UPR markers and apoptotic cell death.

Effects of 4-phenylbutyric acid on the development of diabetic retinopathy in diabetic rats: regulation of endoplasmic reticulum stress-oxidative activation

There are good evidences suggesting that endoplasmic reticulum (ER) stress can be one of the contributing factors in the development of diabetic retinopathy. The present study was designed to investigate the effect of chemical chaperone 4-phenylbutyric acid (4-PBA) in alleviating the ER stress, and diabetic retinopathy in type 2 diabetic rats. Treatment of diabetic rats with 4-PBA, increased the antioxidant capacity, reduced the levels of lipid peroxidation, organised the state of apoptosis and regulated the ER stress – oxidative activation in retinal tissue. Also there was an improvement in the histological picture of retinal specimens compared to untreated diabetic rats. It was concluded that 4-PBA is a promising therapeutic agent for ER stress diseases such as diabetic retinopathy.

Analysis of osteogenesis imperfecta in pathology and the effects of 4-phenylbutyric acid using patient-derived fibroblasts and induced pluripotent stem cells

Analysis of osteogenesis imperfecta in pathology and the effects of 4-phenylbutyric acid using patient-derived fibroblasts and induced pluripotent stem cells

Effect of 4-Phenylbutyric Acid and Tauroursodeoxycholic Acid on Magnesium and Calcium Metabolism in Streptozocin-Induced Type 1 Diabetic Mice

Recent evidence has identified a role of micronutrients, such as magnesium (Mg2+) and calcium (Ca2+), in glycemic control. 4-Phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) are molecular chaperones that can improve protein folding and alleviate endoplasmic reticulum (ER) stress. Increasingly, research is focusing on the association between molecular chaperones and micronutrients. This study established and characterized a mouse model of type 1 diabetes (T1D) and investigated the effect of PBA and TUDCA on Mg2+ and Ca2+ metabolism in these mice. T1D was established in Friend virus B-type mice using multiple low doses of streptozotocin. Mice were administered chaperones. Mg2+and Ca2+ levels in tissues and serum were detected using acid digestion and ICP-MS. At 2 weeks and 2 months after chaperone administration was initiated, Mg2+ levels in the heart, liver, kidney, and serum and Ca2+ levels in spleen and serum of T1D mice were significantly decreased compared with controls; Ca2+ levels in the kidney and muscle of T1D mice were significantly increased; Mg2+ and Ca2+ levels in the heart, liver, kidney, muscle, spleen, and serum were positively correlated in control and T1D mice; and PBA restored renal Mg2+ levels to normal values and TUDCA restored hepatic, renal, and serum Mg2+ levels and renal and serum Ca2+ levels to normal values in T1D mice. PBA restored muscular Ca2+ levels to normal values in T1D mice at 2 months after chaperone or vehicle administration was initiated. Further research is required to investigate the underlying mechanisms by which chaperones regulate micronutrients in diabetes.

Modulatory effect of 4-phenyl butyric acid on hyperoxaluria-induced renal injury and inflammation.

Hyperoxaluria-associated deposition of calcium oxalate crystals results from oxalate-induced renal injury and inflammation. The present study was designed to evaluate the effect of 4-Phenyl butyric acid (4-PBA), a chemical chaperone, in ethylene glycol-induced hyperoxaluria and compare its effect with antioxidant, N-acetyl cysteine (NAC). Male Sprague-Dawley rats were given ethylene glycol in drinking water for 28days to induce hyperoxaluria. 4-PBA and NAC were given by oral gavage. Effect of 4-PBA was analyzed in both prophylactic and curative regimens. After every 7days, 24-h urine samples were analyzed for kidney injury and inflammation markers. Increased amounts of kidney injury markers like Kidney injury molecule-1, Lactate dehydrogenase, and N-acetyl-β-glucoseaminidase were found in the urine of hyperoxaluric rats which were significantly reduced by 4-PBA treatment in both prophylactic and curative regimens. Inflammatory markers IL-1β, IL-6, and MCP-1 were also raised in the urine of hyperoxaluric rats which were significantly decreased by 4-PBA treatment. Hyperoxaluria was accompanied with renal oxidative stress as reflected by decreased glutathione redox status and increased reactive oxygen species which was significantly reduced by 4-PBA treatment. Histological study with H&E and Pizzolato staining showed numerous calcium oxalate crystal deposits in the renal tissues of hyperoxaluric rats. However, no significant crystal deposits were seen in the 4-PBA-treated hyperoxaluric rats. N-acetyl cysteine treatment effectively decreased renal oxidative stress but did not alter the production of inflammatory markers. Collectively, the present study suggested the potential protective effect of 4-PBA in hyperoxaluria-induced renal injury and inflammation.

Effects of 4-phenyl butyric acid on high glucose-induced alterations in dorsal root ganglion neurons

Mechanisms and pathways involving in diabetic neuropathy are still not fully understood but can be unified by the process of overproduction of reactive oxygen species (ROS) such as superoxide, endoplasmic reticulum (ER) stress, downstream intracellular signaling pathways and their modulation. Susceptibility of dorsal root ganglion (DRG) to internal/external hyperglycemic environment stress contributes to the pathogenesis and progression of diabetic neuropathy. ER stress leads to abnormal ion channel function, gene expression, transcriptional regulation, metabolism and protein folding. 4-phenyl butyric acid (4-PBA) is a potent and selective chemical chaperone; which may inhibit ER stress. It may be hypothesized that 4-PBA could attenuate via channels in DRG in diabetic neuropathy. Effects of 4-PBA were determined by applying different parameters of oxidative stress, cell viability, apoptosis assays and channel expression in cultured DRG neurons. Hyperglycemia-induced apoptosis in the DRG neuron was inhibited by 4-PBA. Cell viability of DRG neurons was not altered by 4-PBA. Oxidative stress was significantly blocked by the 4-PBA. Sodium channel expression was not altered by the 4-PBA. Our data provide evidence that the hyperglycemia-induced alteration may be reduced by the 4-PBA without altering the sodium channel expression.

Effects of 4-phenylbutyric acid on chronic cerebral hypoperfusion-induced cognitive dysfunction

Objective To explore the effects of 4-phenylbutyric acid(PBA) on cognitive dysfunction after chronic cerebral hypoperfusion and underlying mechanisms. Methods 62 male Sprague Dawley rats in clean degree were divided into sham group(n=14), chronic cerebral ischemia group(bilateral carotid arteries occlusion, 2VO group, n=24), and chronic cerebral ischemia with PBA treatment(2VO+ PBA group, n=24). The chronic cerebral ischemia models were produced by the occlusion of bilateral common caroid artery for 1 month. During the hypoperfusion, the rats were injected intraperitoneally with 11.25 mg·ml-1 PBA(90 mg·kg-1·d-1) or equal volume of saline once a day for 3 days followed by every other day for 27 days. Learning and memory abilities were tested by Morris water maze and novel object recognition test. The expression and distribution of NR2A in hippocampus were examined by Western blot and immunohistochemistry. Results Morris water maze test showed that the 2VO group had significantly longer latent time than sham group in searching platform (P 0.05). Immunohistochemistry data was consistent with the data of Western blot for NR2A level and distribution. The ratio of p-CREB/total CREB in 2VO group(0.62±0.04) was remarkably lower than that in sham group(1.00±0.07), but the ratio of p-CREB/total CREB in 2VO+ PBA group(0.97±0.07) was remarkably higher than that in 2VO group(P<0.01). Conclusion NR2A reduction is associated with chronic cerebral hypoperfusion-induced cognitive impairment, which is rescued by the PBA treatment. It suggests that PBA may have a therapeutic effect on preventing chronic cerebral hypoperfusion-induced cognitive impairment. Key words: Chronic cerebral hypoperfusion; 4-phenylbutyric acid; Cognitive dysfunction

Effects of 4-phenylbutyric acid on carbon tetrachloride-induced acute liver injury in mice

To explore the effects and the molecular mechanisms of 4-phenylbutyric acid (PBA) on carbon tetraehloride (CCl4)-induced acute liver injury in mice. Sixty adult, healthy, male ICR mice were divided equally into the control group, PBA group, CCl4 12 h group, CCl4 24 h group, CCl4 48 h group, CCl4 72 h group, PBA+CCl4 12 h group, PBA+CCl4 24 h group, PBA+CCl4 48 h group, and PBA+CCl4 72 h group. The CCl4 groups and the PBA+CCl4 groups were intraperitoneally (i.p.) injected with CCl4 (300 mL/kg). In the PBA+CCl4 groups, the mice were i.p. injected with PBA (400 mg/kg). All mice were sacrificed to collect blood and liver specimens at different time points after the CCl4 treatment. Serum alanine aminotransferase (ALT) was detected. Histological examination was performed using hematoxylin-eosin staining and light microscopy, and apoptosis was detected using terminal transferase dUTP nick end labeling. The hepatic distribution of proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. The hepatic protein expression of glucose-regulated protein (GRP78), C/EBP homologousprotein (CHOP), phosphorylated c-Jun N-terminal kinases (p-JNK), phosphorylated eukaryotic initiation factor 2a subunit (p-eIF2a), phosphorylated serine threonine kinase (p-akt), and nuclear factor-kappa B p65 (NF-kappa Bp65) were determined by western blot. The serum ALT level in the PBA+CCl4 groups was reduced as compared with that in the CCl4 groups at the various time points examined.The liver-to-body weight ratio of two groups showed a significant difference only at the 48 h time point (P<0.01). PBA reduced the degree of hepatic necrosis and apoptosis caused by CCl4, and reduced the expression of hepatic GRP78 and other endoplasmic reticulum stress-related proteins (P<0.01). The protein levels of p-akt, NF-kappa Bp65 and PCNA was significantly decreased in the PBA+CCl4 groups (P<0.01). The endoplasmic reticulum stress inhibitor PBA alleviated acute hepatic necrosis and apoptosis but restrained hepatic proliferation.

Growth inhibitory effect of 4-phenyl butyric acid on human gastric cancer cells is associated with cell cycle arrest

To investigate the growth effects of 4-phenyl butyric acid (PBA) on human gastric carcinoma cells and their mechanisms. Moderately-differentiated human gastric carcinoma SGC-7901 and lowly-differentiated MGC-803 cells were treated with 5, 10, 20, 40, and 60 μmol/L PBA for 1-4 d. Cell proliferation was detected using the MTT colorimetric assay. Cell cycle distributions were examined using flow cytometry. The proliferation of gastric carcinoma cells was inhibited by PBA in a dose- and time-dependent fashion. Flow cytometry showed that SGC-7901 cells treated with low concentrations of PBA were arrested at the G₀/G₁ phase, whereas cells treated with high concentrations of PBA were arrested at the G₂/M phase. Although MGC-803 cells treated with low concentrations of PBA were also arrested at the G₀/ G₁ phase, cells treated with high concentrations of PBA were arrested at the S phase. The growth inhibitory effect of PBA on gastric cancer cells is associated with alteration of the cell cycle. For moderately-differentiated gastric cancer cells, the cell cycle was arrested at the G₀ /G₁ and G₂/M phases. For lowly-differentiated gastric cancer cells, the cell cycle was arrested at the G₀/G₁ and S phases.

Effects of 4-phenylbutyric acid on the process and development of diabetic nephropathy induced in rats by streptozotocin: Regulation of endoplasmic reticulum stress-oxidative activation

Oxidative stress may contribute to the pathogenesis of diabetic nephropathy (DN), although the precise regulatory mechanism is still unclear. Recent reports have shown that chemical molecular chaperone 4-phenylbutyric acid (4-PBA) can suppress oxidative stress by attenuating endoplasmic reticulum (ER) stress. We therefore hypothesized that 4-PBA could provide renoprotection through the suppression of oxidative stress in DN rats. Male Sprague–Dawley (SD) rats were randomly divided into three groups: a normal control (NC) group, a streptozotocin (STZ)-induced DN model group, and a DN plus 4-PBA (1 g/kg) treatment group. At the end of 4, 8, and 12 weeks, hydroxyproline content, NADPH oxidase activity and the expression of phosphorylation of inositol-requiring enzyme-1α (p-IRE1α), p47phox, nitrotyrosine (NT) and NF-E2-related factor 2 (Nrf2) in the kidneys of all rats were determined; malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity in serum and urine were also detected; renal nuclear factor κB (NF-κB) activity in all of the rats was examined at the end of 12 weeks. Compared with the NC group, the DN rats showed a significant increase in hydroxyproline content, NADPH oxidase activity, NF-κB activity, the expression of p-IRE1α, p47phox, NT and Nrf2 in renal tissue; markedly, MDA levels were higher and SOD activity was lower in serum and urine of DN rats than in NC rats for the indicated time. These alterations were inhibited by the administration of 4-PBA. These findings first demonstrated that treatment with 4-PBA significantly inhibits the process and development of diabetic nephropathy in rats through the regulation of ER stress-oxidative activation.

4‐Phenyl butyric acid does not generally reduce glucose levels in rodent models of diabetes

1. Endoplasmic reticulum (ER) stress plays a role in the pathogenesis of diabetes. The aim of the present study was to investigate the effect of 4-phenyl butyric acid (PBA), a novel chemical chaperone reducing ER stress, on serum glucose level in different strains of normal and diabetic rodents. 2. 4-Phenyl butyric acid (1 g/kg per day, i.g.) was administered to ob/ob Type 2 diabetic mice, alloxan-induced Type 1 diabetic mice and hydrocortisone (HC)-induced Type 2 diabetic mice as well as normal C57BL/6J mice and Kumming mice for 14 days to evaluate its effect on serum glucose levels. In addition, mice were treated simultaneously with PBA (1 g/kg per day) and HC for 9 days to determine its preventive effect against the development of insulin resistance. PBA (0.7 and 1.4 g/kg per day) was administered to non-obese Type 2 diabetic Goto-Kakizaki (GK) and normal Wistar-Kyoto (WKY) rats for 14 and 7 days, respectively, to determine its effects on serum glucose levels. 3. 4-Phenyl butyric acid significantly reduced serum glucose levels in obese Type 2 diabetic ob/ob mice. Normoglycaemia was obtained in ob/ob mice after 4 days of PBA treatment and was maintained for up to 14 days treatment. 4. 4-Phenyl butyric acid had no glucose-lowering effect in alloxan-induced Type 1 diabetic mice, HC-induced Type 2 diabetic mice and non-obese Type 2 diabetic GK rats. In addition, it had no beneficial effects on insulin resistance in HC-treated mice. 5. 4-Phenyl butyric acid did not affect normal serum glucose levels in C57BL/6 J mice, Kunming mice or WKY rats. 6. In conclusion, PBA does not generally reduce glucose levels in rodent models of diabetes, although it can normalize glucose levels in ob/ob diabetic mice, indicating that restoration of ER function as diabetes therapy is limited to conditions under which ER stress is involved in the high glucose levels.