Biomimetic Porous Ti6Al4V Implants: A Novel Interbody Fusion Cage via Gel-Casting Technique to Promote Spine Fusion.

An interbody fusion cage (Cage) is crucial in spinal decompression and fusion procedures for restoring normal vertebral curvature and rebuilding spinal stability. Currently, these Cages suffer from issues related to mismatched elastic modulus and insufficient bone integration capability. Therefore, a gel-casting technique is utilized to fabricate a biomimetic porous titanium alloy material from Ti6Al4V powder. The biomimetic porous Ti6Al4V is compared with polyetheretherketone (PEEK) and 3D-printed Ti6Al4V materials and their respective Cages. Systematic validation is performed through mechanical testing, in vitro cell, in vivo rabbit bone defect implantation, and ovine anterior cervical discectomy and fusion experiments to evaluate the mechanical and biological performance of the materials. Although all three materials demonstrate good biocompatibility and osseointegration properties, the biomimetic porous Ti6Al4V, with its excellent mechanical properties and a structure closely resembling bone trabecular tissue, exhibited superior bone ingrowth and osseointegration performance. Compared to the PEEK and 3D-printed Ti6Al4V Cages, the biomimetic porous Ti6Al4V Cage outperforms in terms of intervertebral fusion performance, achieving excellent intervertebral fusion without the need for bone grafting, thereby enhancing cervical vertebra stability. This biomimetic porous Ti6Al4V Cage offers cost-effectiveness, presenting significant potential for clinical applications in spinal surgery.

Risk factors for delayed postoperative hyponatremia in patients with non-functioning pituitary adenomas undergoing transsphenoidal surgery: A single-institution study.

Purpose: We aimed to assess factors influencing the occurrence of delayed hyponatremia after transsphenoidal surgery (TSS) in patients with a non-functional pituitary adenoma (NFPA). Methods: We retrospectively collected the clinical data of patients who underwent TSS for NFPA between January 2016 and January 2021. The pituitary region was preoperatively scanned with 3.0 T magnetic resonance imaging. The risk factors for delayed postoperative hyponatremia for NFPA were identified by univariate and multivariable logistic regression analysis. Results: We selected 166 patients with NFPA who fulfilled the inclusion criteria. Delayed postoperative hyponatremia occurred in 28 patients and did not in 138. Multivariable logistic regression analyses demonstrated that higher odds of developing delayed postoperative hyponatremia were independently associated with larger craniocaudal dimension (OR = 1.128, P = 0.034), as well as preoperative hyperprolactinemia (OR = 2.618, P = 0.045) and larger preoperative pituitary stalk deviation angle (OR = 3.033, P = 0.022). Conclusion: We identified the independent risk factors for delayed hyponatremia after TSS for NFPA; these included preoperative hyperprolactinemia, craniocaudal diameter, and preoperative pituitary stalk deviation angle.

Polß modulates the expression of type I interferon via STING pathway.

DNA Polymerase ß (Polß) is a key enzyme in base excision repair (BER), which is very important in maintaining the stability and integrity of the genome. Mutant Polß is closely associated with carcinogenesis. However, Polß is highly expressed in most cancers, but the underlying mechanism is not well understood. Here, we found that breast cancer cells MCF-7 with Polß knockdown exhibited high levels of type I interferon and were easily eliminated by natural killer (NK) cells.Similarly, Polß-mutant (R137Q) mice exhibited chronic inflammation symptoms in multiple organs and upregulated type I interferon levels. Further results showed that Polß deficiency caused more DNA damage accumulation in cells and triggered the leakage of damaged DNA into the cytoplasm, which activated the STING/IRF3 pathway, promoted phosphorylated IRF3 translocating into the nucleus and enhanced the expression of type I interferon and proinflammatory cytokines. In addition, this effect could be eliminated by Polß overexpression, STING inhibitor or STING knockdown. Taken together, our findings provide mechanistic insight into the role of Polß in cancers by linking DNA repair and the inflammatory STING pathway.

When immunotherapy meets surgery in non-small cell lung cancer.

The results of the most recent Checkmate-816 trial in The New England Journal of Medicine using combination neoadjuvant immunotherapy with platinum-based chemotherapy in resectable non-small cell lung cancer demonstrate the effectiveness of neoadjuvant immunotherapy and provide further support that biology and personalized therapy represent the foundation of lung cancer treatment.

Microscopic Transsphenoidal Resection of Giant Pituitary Adenomas: Analysis of the Factors Limiting the Degree of Resection in 73 Cases.

Purpose: To analyze the risk factors affecting the gross-total resection of giant pituitary adenomas using a transsphenoidal approach under a microscope to provide a reference basis for formulating an appropriate surgical strategy. Methods: The clinical data of patients who underwent microscopic transsphenoidal resection of giant pituitary adenomas in a single center from January 2011 to December 2020 were retrospectively analyzed. Based on magnetic resonance imaging and surgical records, the predictive factors affecting the gross-total resection of giant pituitary adenomas under microscopy were determined through univariate and multivariate analyses. Results: A total of 73 patients with giant pituitary adenomas underwent transsphenoidal microsurgery. Gross-total resection was performed in 19 cases (26%), subtotal resection in 31 cases (42%), partial resection in 21 cases (29%), and the degree of resection was <50% in only two cases (3%). After binary logistic analysis, it was found that it was more difficult to completely remove giant pituitary adenomas with a Knosp grade 3-4 [odds ratio (OR) = 0.214, 95% confidence interval (CI): 0.05-0.917; P = 0.038], greater proportion of tumor suprasellar volume (odds ratio = 0.937, 95% confidence interval: 0.898-0.978; P = 0.003), and intraoperative evidence of invasion of the cavernous sinus (odds ratio = 0.187, 95% CI: 0.039-0.898; P = 0.036). Conclusion: It is difficult to remove a giant pituitary adenoma invading the cavernous sinus completely with a higher degree of invasion of the suprasellar region using microscopic transsphenoidal surgery. The combined application of multiple surgical methods can help to improve the degree of resection during a single operation.

Toward personalized treatment approaches for non-small-cell lung cancer.

Worldwide, lung cancer is the most common cause of cancer-related deaths. Molecular targeted therapies and immunotherapies for non-small-cell lung cancer (NSCLC) have improved outcomes markedly over the past two decades. However, the vast majority of advanced NSCLCs become resistant to current treatments and eventually progress. In this Perspective, we discuss some of the recent breakthrough therapies developed for NSCLC, focusing on immunotherapies and targeted therapies. We highlight our current understanding of mechanisms of resistance and the importance of incorporating genomic analyses into clinical studies to decipher these further. We underscore the future role of neoadjuvant and maintenance combination therapy approaches to potentially cure early disease. A major challenge to successful development of rational combination therapies will be the application of robust predictive biomarkers for clear-cut patient stratification, and we provide our views on clinical research areas that could influence how NSCLC will be managed over the coming decade.

Agonistic CD40 Antibodies in Cancer Treatment.

CD40 is expressed on a variety of antigen-presenting cells. Stimulation of CD40 results in inflammation by upregulation of other costimulatory molecules, increased antigen presentation, maturation (licensing) of dendritic cells, and activation of CD8+ T cells. Here we analyzed gene expression data from The Cancer Genome Atlas in melanoma, renal cell carcinoma, and pancreatic adenocarcinoma and found correlations between CD40 and several genes involved in antigen presentation and T cell function, supporting further exploration of CD40 agonists to treat cancer. Agonist CD40 antibodies have induced anti-tumor effects in several tumor models and the effect has been more pronounced when used in combination with other treatments (immune checkpoint inhibition, chemotherapy, and colony-stimulating factor 1 receptor inhibition). The reduction in tumor growth and ability to reprogram the tumor microenvironment in preclinical models lays the foundation for clinical development of agonistic CD40 antibodies (APX005M, ChiLob7/4, ADC-1013, SEA-CD40, selicrelumab, and CDX-1140) that are currently being evaluated in early phase clinical trials. In this article, we focus on CD40 expression and immunity in cancer, agonistic human CD40 antibodies, and their pre-clinical and clinical development. With the broad pro-inflammatory effects of CD40 and its ligand on dendritic cells and macrophages, and downstream B and T cell activation, agonists of this pathway may enhance the anti-tumor activity of other systemic therapies.

Gigantol Attenuates the Metastasis of Human Bladder Cancer Cells, Possibly Through Wnt/EMT Signaling.

BACKGROUND: Bladder cancer has long been recognized as one of the most common and aggressive human malignant carcinomas due to the increased invasiveness and metastasis. The discovery and development of natural compounds from Dendrobium species for cancer therapy have garnered increasing attention in recent years. Among those natural elements, the bibenzyl compound gigantol has promising therapeutic potential against several cancer cell lines; however, its roles on bladder tumor metastasis have not been investigated. MATERIALS AND METHODS: Here in this in vitro study, we utilized viability tests, cell migration, cell invasion and apoptosis assays to evaluate the anti-tumor activity of gigantol on three human bladder cancer cell lines (SW780, 5637, and T24) and a normal human bladder cell line (SVHUC-1). Cells were treated with different concentrations of gigantol (0, 40, 80, and 160 µM) for 24, 48 and 72 h. RESULTS: Here in this study, we showed that gigantol suppressed cancer cell proliferation but not normal SVHUC-1 cells. The inhibitory effect of the compound on cell migration and invasion was also exhibited in the cancer cell lines. Cell apoptosis assay by flow cytometry revealed enhanced apoptotic effects of gigantol on cancer cells. Gene expression analysis revealed that Wnt/EMT signaling might involve in the response of bladder cancer cells to gigantol. CONCLUSION: Therefore, the present data demonstrate gigantol as a strong anticancer reagent against bladder cancer possibly through Wnt/EMT signaling.

Neonatal Isoflurane Anesthesia or Disruption of Postsynaptic Density-95 Protein Interactions Change Dendritic Spine Densities and Cognitive Function in Juvenile Mice.

BACKGROUND: Experimental evidence shows postnatal exposure to anesthesia negatively affects brain development. The PDZ2 domain, mediating protein-protein interactions of the postsynaptic density-95 protein, serves as a molecular target for several inhaled anesthetics. The authors hypothesized that early postnatal disruption of postsynaptic density-95 PDZ2 domain interactions has persistent effects on dendritic spines and cognitive function. METHODS: One-week-old mice were exposed to 1.5% isoflurane for 4 h or injected with 8 mg/kg active postsynaptic density-95 wild-type PDZ2 peptide along with their respective controls. A subset of these mice also received 4 mg/kg of the nitric oxide donor molsidomine. Hippocampal spine density, long-term potentiation, novel object recognition memory, and fear learning and memory were evaluated in mice. RESULTS: Exposure of 7-day-old mice to isoflurane or postsynaptic density-95 wild-type PDZ2 peptide relative to controls causes: (1) a long-term decrease in mushroom spines at 7 weeks (mean ± SD [spines per micrometer]): control (0.8 ± 0.2) versus isoflurane (0.4 ± 0.2), P < 0.0001, and PDZ2MUT (0.7 ± 0.2) versus PDZ2WT (0.4 ± 0.2), P < 0.001; (2) deficits in object recognition at 6 weeks (mean ± SD [recognition index]): naïve (70 ± 8) versus isoflurane (55 ± 14), P = 0.010, and control (65 ± 13) versus isoflurane (55 ± 14), P = 0.045, and PDZ2MUT (64 ±11) versus PDZ2WT (53 ± 18), P = 0.045; and (3) deficits in fear learning at 7 weeks and memory at 8 weeks (mean ± SD [% freezing duration]): Learning, control (69 ± 12) versus isoflurane (52 ± 13), P < 0.0001, and PDZ2MUT (65 ± 14) versus PDZ2WT (55 ± 14) P = 0.011, and Memory, control (80 ± 17) versus isoflurane (56 ± 23), P < 0.0001 and PDZ2MUT (73 ± 18) versus PDZ2WT (44 ± 19) P < 0.0001. Impairment in long-term potentiation has fully recovered here at 7 weeks (mean ± SD [% baseline]): control (140 ± 3) versus isoflurane (137 ± 8), P = 0.560, and PDZ2MUT (136 ± 17) versus PDZ2WT (128 ± 11), P = 0.512. The isoflurane induced decrease in mushroom spines was preventable by introduction of a nitric oxide donor. CONCLUSIONS: Early disruption of PDZ2 domain-mediated protein-protein interactions mimics isoflurane in decreasing mushroom spine density and causing learning and memory deficits in mice. Prevention of the decrease in mushroom spine density with a nitric oxide donor supports a role for neuronal nitric oxide synthase pathway in mediating this cellular change associated with cognitive impairment.

DNA polymerase beta modulates cancer progression via enhancing CDH13 expression by promoter demethylation.

DNA polymerase ß (Pol ß) plays a critical role in DNA base excision repair (BER), which is involved in maintaining genomic stability and in the modulation of DNA demethylation. Numerous studies implicated deficiency of Pol ß in the genomic instability and dysregulation of genes expression, leading to affecting initiation of cancer. However, the role of Pol ß in cancer progression is still unclear. Here, we show that Pol ß depresses migratory and invasive capabilities of both breast and lung carcinomas, which were evident in human breast and lung cancer cells, as well as in mouse xenograft tumors. On the molecular basis, overexpression of Pol ß enhanced expression of CDH13, which show function on cell adhesion and migration. Knockdown of CDH13 restores the migratory, invasive capabilities and angiogenesis in tumor, which gets impaired by Pol ß. According to the function of BER on modulation of DNA demethylation, our studies on CDH13 expression and the DNA methylation levels of CDH13 promoter suggested that Pol ß promotes expression of CDH13 by augmenting DNA demethylation of CDH13 promoter. Our findings elucidated a novel possibility that Pol ß impair cancer cell metastasis during cancer progression and shed light on the role of Pol ß in cancer therapy.

Src-mediated phosphorylation of GAPDH regulates its nuclear localization and cellular response to DNA damage.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme involved in energy metabolism. Recently, GAPDH has been suggested to have extraglycolytic functions in DNA repair, but the underlying mechanism for the GAPDH response to DNA damage remains unclear. Here, we demonstrate that the tyrosine kinase Src is activated under DNA damage stress and phosphorylates GAPDH at Tyr41. This phosphorylation of GAPDH is essential for its nuclear translocation and DNA repair function. Blocking the nuclear import of GAPDH by suppressing Src signaling or through a GAPDH Tyr41 mutation impairs its response to DNA damage. Nuclear GAPDH is recruited to DNA lesions and associates with DNA polymerase ß (Pol ß) to function in DNA repair. Nuclear GAPDH promotes Pol ß polymerase activity and increases base excision repair (BER) efficiency. Furthermore, GAPDH knockdown dramatically decreases BER efficiency and sensitizes cells to DNA damaging agents. Importantly, the knockdown of GAPDH in colon cancer SW480 cells and xenograft models effectively enhances their sensitivity to the chemotherapeutic drug 5-FU. In summary, our findings provide mechanistic insight into the new function of GAPDH in DNA repair and suggest a potential therapeutic target in chemotherapy.

Dysregulation of microRNA-125a contributes to obesity-associated insulin resistance and dysregulates lipid metabolism in mice.

Obesity is associated with an increased risk of developing insulin resistance (IR) and type 2 diabetes (T2D). A diverse group of factors including miRNA has been implicated in the pathogenesis of these two metabolic conditions, although underlying molecular mechanisms involved are not well defined. Here, we provide evidence that hepatic miR-125a levels are diminished in both genetic as well as dietary mouse models of obesity. Overexpression of miR-125a enhanced insulin signaling and attenuated cellular lipid accumulation in HepG2 cells and Hepa1-6 cells. Likewise, treatment of mice with ago-miR-125a increased insulin sensitivity, similar to overexpression of miR-125a, whereas treatment of mice with antago-miR-125a blunted the insulin sensitivity. Furthermore, overexpression of miR-125a in mice previously fed a high-fat diet (HFD), significantly improved insulin sensitivity, and attenuated obesity-linked hepatic steatosis and hepatocyte lipid accumulation. In addition, we show that ELOVL fatty acid elongase 6 (Elovl6) is a direct target of miR-125a, and participates in miR-125a mediated regulation of insulin sensitivity and lipid metabolism. These data led us to conclude that dysregulated miR-125a expression augments the development of obesity-induced IR and that miR-125a might serve as a therapeutic target for the development of new drug(s) in the clinical management of metabolic diseases.

MicroRNA-140 impedes DNA repair by targeting FEN1 and enhances chemotherapeutic response in breast cancer.

An increased DNA repair capacity is associated with drug resistance and limits the efficacy of chemotherapy in breast cancers. Flap endonuclease 1 (FEN1) participates in various DNA repair pathways and contributes to cancer progression and drug resistance in chemotherapy. Inhibition of FEN1 serves as a potent strategy for cancer therapy. Here, we demonstrate that microRNA-140 (miR-140) inhibits FEN1 expression via directly binding to its 3' untranslated region, leading to impaired DNA repair and repressed breast cancer progression. Overexpression of miR-140 sensitizes breast cancer cells to chemotherapeutic agents and overcomes drug resistance in breast cancer. Notably, ectopic expression of FEN1 abates the effects of miR-140 on DNA damage and the chemotherapy response in breast cancer cells. Furthermore, the transcription factor/repressor Ying Yang 1 (YY1) directly binds to the miR-140 promoter and activates miR-140 expression, which is attenuated in doxorubicin resistance. Our results demonstrate that miR-140 acts as a tumor suppressor in breast cancer by inhibiting FEN1 to repress DNA damage repair and reveal miR-140 to be a new anti-tumorigenesis factor for adjunctive breast cancer therapy. This novel mechanism will enhance the treatment effect of chemotherapy in breast cancer.

Enhanced Activity of Variant DNA Polymerase ß (D160G) Contributes to Cisplatin Therapy by Impeding the Efficiency of NER.

Cisplatin, commonly used in a variety of cancer treatments, induces apoptosis in cancer cells by causing lethal DNA damage. Several DNA repair pathways participate in regulation of cisplatin treatment, leading to cisplatin sensitivity or resistance in cancer cells. DNA polymerase ß (pol ß), a key protein involved in base excision repair, confers a response to cisplatin therapy that is dependent on polymerase activity. Pol ß D160G mutation with enhanced polymerase activity, previously identified in clear cell renal cell carcinoma, enhances the sensitivity of human cancer cells and mouse xenografts to cisplatin by limiting the efficiency of nucleotide excision repair (NER). Notably, the D160G mutation impedes the recruitment of XPA to cisplatin-induced sites of DNA damage, leading to unrepaired damage and further inducing cell death. Molecular architecture analysis indicated that the D160G mutation alters protein-DNA interactions and the surface electrostatic properties of the DNA-binding regions, resulting in greater DNA affinity and polymerase activity compared with wild-type pol ß. Collectively, these results indicate that enhancing pol ß activity impedes the efficiency of NER and provide a promising adjuvant therapeutic strategy for cisplatin chemotherapy. IMPLICATIONS: Our studies demonstrate that polß D160G mutation with enhanced polymerase activity impedes NER efficiency during the repair of cisplatin-induced DNA damage, leading to increased cisplatin sensitivity in cancer cells.

Obesity-induced overexpression of miRNA-24 regulates cholesterol uptake and lipid metabolism by targeting SR-B1.

Scavenger Receptor B1 (SR-B1) is an 82 kDa integral membrane glycoprotein that mediates selective uptake of high-density lipoprotein cholesteryl ester (CE) in vitro and in vivo. Previously, we defined several kinds of regulatory mechanisms of SR-B1 expression and function. Here, we have dissected the function of a novel miR-24 on SR-B1 expression, HDL uptake and lipid metabolism. We showed that miR-24 was upregulated in HepG2 cells cultured in the mimicked hyperlipidemic condition and in the livers of dietary induced and genetic obesity mice. Overexpression of miR-24 inhibited SR-B1 expression by directly targeting SR-B1 3' UTR and repressed HDL uptake and steroidogenesis in steroidogenic cells. HepG2 cells with miR-24 showed attenuation of TG levels and lipid accumulation. Moreover, we validated that overexpression of miR-24 downregulated the expression of certain genes involved in lipogenesis, FASN, ACLY and SCD1, and increased the expression of genes of cholesterol synthesis, HMGCR, DHCR24 and SREBP2. Taken together, we demonstrated that obesity induced miR-24 repressed HDL uptake, steroid hormone synthesis and lipid metabolism by targeting SR-B1.

Gigantol inhibits Wnt/ß-catenin signaling and exhibits anticancer activity in breast cancer cells.

BACKGROUND: Gigantol is a bibenzyl compound derived from several medicinal orchids. This biologically active compound has been shown to have promising therapeutic potential against cancer cells, but its mechanism of action remains unclear. METHODS: The inhibitory effect of gigantol on Wnt/ß-catenin signaling was evaluated with the SuperTOPFlash reporter system. The levels of phosphorylated low-density lipoprotein receptor related protein 6 (LRP6), total LRP6 and cytosolic ß-catenin were determined by Western blot analysis. The expression of Wnt target genes was analyzed using real-time PCR. Cell viability was measured with a MTT assay. The effect of gigantol on cell migration was examined using scratch wound-healing and transwell migration assays. RESULTS: Gigantol decreased the level of phosphorylated LRP6 and cytosolic ß-catenin in HEK293 cells. In breast cancer MDA-MB-231 and MDA-MB-468 cells, treatment with gigantol reduced the level of phosphorylated LRP6, total LRP6 and cytosolic ß-catenin in a dose-dependent manner, resulting in a decrease in the expression of Wnt target genes Axin2 and Survivin. We further demonstrated that gigantol suppressed the viability and migratory capacity of breast cancer cells. CONCLUSION: Gigantol is a novel inhibitor of the Wnt/ß-catenin pathway. It inhibits Wnt/ß-catenin signaling through downregulation of phosphorylated LRP6 and cytosolic ß-catenin in breast cancer cells.

Glutathione-stabilized Cu nanocluster-based fluorescent probe for sensitive and selective detection of Hg2+ in water.

In this paper, an innovative and facile one-pot method for synthesizing water-soluble and stable fluorescent Cu nanoclusters (CuNCs), in which glutathione (GSH) served as protecting ligand and ascorbic acid (AA) as reducing agent was reported. The resultant CuNCs emitted blue-green fluorescence at 440 nm, with a quantum yield (QD) of about 3.08%. In addition, the prepared CuNCs exhibited excellent properties such as good water solubility, photostability and high stability toward high ionic strength. On the basis of the selective quenching of Hg2+ on CuNCs fluorescence, which may be the result of Hg2+ ion-induced aggregation of the CuNCs, the CuNCs was used for the selective and sensitive determination of Hg2+ in aqueous solution. The proposed analytical strategy permitted detection of Hg2+ in a linear range of 4 × 10-8 to 6 × 10-5  M, with a detection limit of 2.2 × 10-8  M. Eventually, the practicability of this sensing approach was confirmed by its successful application to assay Hg2+ in tap water, Lotus lake water and river water samples with the quantitative spike recoveries ranging from 96.9% to 105.4%.

Feedback inhibition of CREB signaling by p38 MAPK contributes to the negative regulation of steroidogenesis.

BACKGROUND: Steroidogenesis is a complex, multi-steps biological process in which, cholesterol precursor is converted to steroids in a tissue specific and tropic hormone dependent manner. Given that steroidogenesis is achieved by coordinated functioning of multiple tissue specific enzymes, many steroids intermediates/metabolites are generated during this process. Both the steroid products as well as major lipoprotein cholesterol donor, high-density lipoprotein 3 (hHDL3) have the potential to negatively regulate steroidogenesis via increased oxidative stress/reactive oxygen species (ROS) generation. METHODS: In the current study, we examined the effects of treatment of a mouse model of steroidogenesis, Y1-BS1 adrenocortical tumor cells with pregnenolone, 22(R)-Hydroxycholesterol [22(R)-diol] or hHDL3 on ROS production, phosphorylation status of p38 MAPK and cAMP response element-binding protein (CREB), CREB transcriptional activity and mRNA expression of StAR, CPY11A1/P450scc and antioxidant enzymes, superoxide dismutases [Cu,ZnSOD (SOD1), MnSOD (SOD2)], catalase (CAT) and glutathione peroxidase 1 (GPX1). We also detected the steroid product in p38 MAPK inhibitor treated Y1 cells by HPLC-MS / MS. RESULTS: Treatment of Y1 cells with H2O2 greatly enhanced the phosphorylation of both p38 MAPK and CREB protein. Likewise, treatment of cells with pregnenolone, 22(R) diol or hHDL3 increased ROS production measured with the oxidation-sensitive fluorescent probe 2',7'-Dichlorofluorescin diacetate (DCFH-DA). Under identical experimental conditions, treatment of cells with these agents also increased the phosphorylation of p38 MAPK and CREB. This increased CREB phosphorylation however, was associated with its decreased transcriptional activity. The stimulatory effects of pregnenolone, 22(R)-diol and hHDL3 on CREB phosphorylation was abolished by a specific p38 MAPK inhibitor, SB203580. Pregnenolone, and 22(R) diol but not hHDL3 upregulated the mRNA expression of SOD1, SOD2 and GPX1, while down-regulated the mRNA levels of StAR and CYP11A1. The p38 inhibitor SB203580 could increase the steroid production in HDL3, 22(R)-diol or pregnenolone treated cells. CONCLUSION: Our data demonstrate induction of a ROS/p38 MAPK -mediated feedback inhibitory pathway by oxy-cholesterol and steroid intermediates and products attenuates steroidogenesis via inhibition of CREB transcriptional activity.