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Ionising radiation exposure can lead to acute haematopoietic radiation syndrome. Despite significant advancements in the field of radioprotection, no drugs with high efficacy and low toxicity have yet been approved by the Food and Drug Administration. FG‐4592, as a proline hydroxylase inhibitor, may play an important role in radioprotection of the haematopoietic system. Mice were peritoneal injected with FG‐4592 or normal saline. After irradiation, the survival time, body weight, peripheral blood cell and bone marrow cell (BMC) count, cell apoptosis, pathology were analysed and RNA‐sequence technique (RNA‐Seq) was conducted to explore the mechanism of FG‐4592 in the haematopoietic system. Our results indicated that FG‐4592 improved the survival rate and weight of irradiated mice and protected the spleen, thymus and bone marrow from IR‐induced injury. The number of BMCs was increased and protected against IR‐induced apoptosis. FG‐4592 also promoted the recovery of the blood system and erythroid differentiation. The results of RNA‐Seq and Western blot showed that the NF‐κB signalling pathway and hypoxia‐inducible factor‐1 (HIF‐1) signalling pathway were upregulated by FG‐4592. Meanwhile, RT‐PCR results showed that FG‐4592 could promote inflammatory response significantly. FG‐4592 exhibited radioprotective effects in the haematopoietic system by promoting inflammatory response and targeting the NF‐κB, HIF signalling pathway. [ABSTRACT FROM AUTHOR]

Background: For diabetic ulcers, the impaired response to hypoxia is a key feature associated with delayed healing. In the early phase of hypoxia, hypoxic signaling activates the AMPK system through direct phosphorylation of the PHD2 pathway, producing a significant endogenous hypoxic protective effect. Methods: Twenty Sprague-Dawley (SD) rats were randomly divided into two groups: treatment (sh-PHD2) and control (sh-Control). Using lentiviral encapsulation of PHD2-shRNA and transfection, the silencing efficiency of PHD2 expression was verified in rat dermal fibroblasts (RDF) and in rat aortic endothelial cells (RAECs). Changes in the ability of RDF and RAECs to proliferate, migrate, and in the rate of ATP production were observed and then tested after inhibition of AMPK phosphorylation using dorsomorphin. The lentiviral preparation was injected directly into the wounds of rats and wound healing was recorded periodically to calculate the healing rate. Wounded tissues were excised after 14 days and the efficiency of PHD2 silencing, as well as the expression of growth factors, was examined using molecular biology methods. Histological examination was performed to assess CD31 expression and therefore determine effects on angiogenesis. Results: Lentiviral-encapsulated PHD2-sh-RNA effectively suppressed PHD2 expression and improved the proliferation, migration, and ATP production rate of RDF and RAEC, which were restored to their previous levels after inhibition of AMPK. The rate of wound healing, vascular growth, and expression of growth factors were significantly improved in diabetic-model rats after local silencing of PHD2 expression. Conclusion: Silencing of PHD2 promoted wound healing in diabetic-model SD rats by activating AMPK phosphorylation. [ABSTRACT FROM AUTHOR]

Mitochondrial autophagy plays a contributary role in the pathogenesis of retina degeneration (RD). ZYAN1 is a novel proline hydroxylase domain (PHD) inhibitor that can enhance the expression of hypoxia-inducible factor 1-alpha (HIF-1α). This study investigated whether ZYAN1 could alleviate progressive photoreceptor loss and oxidative damage in a pharmacologically induced RD model via the modulation of mitophagy. ZYAN1 was injected into the vitreous body of the RD model, and the retinal autophagy level was analyzed. The therapeutic effects of ZYAN1 were evaluated via a function examination, a morphological assay, in situ reactive oxygen species (ROS) detection, and an immunofluorescence assay. It was shown that the thickness of the outer nuclear layer (ONL) increased significantly, and visual function was efficiently preserved via ZYAN1 treatment. The mitochondria structure of photoreceptors was more complete in the ZYAN1-treated mice, and the number of autophagosomes also increased significantly. Membrane disc shedding and ROS overproduction were alleviated after ZYAN1 treatment, and the axonal cilia were more structurally intact. A Western blot analysis showed that the expression levels of the autophagy-related proteins LC3-B, Beclin-1, and ATG5 increased significantly after ZYAN1 treatment, while the expression of P62 was down-regulated. Moreover, the expression levels of HIF-1α and BNIP3 were up-regulated after ZYAN1 treatment. Therefore, an intravitreal injection of ZYAN1 can act as part of the pharmacologic strategy to modulate mitophagy and alleviate oxidative stress in RD. These findings enrich our knowledge of RD pathology and provide insights for the discovery of a therapeutic molecule. [ABSTRACT FROM AUTHOR]

Collagen is a kind of high macromolecular protein with unique tissue distribution and distinctive functions in the body. At present, most collagen products are extracted from the tissues and organs of mammals or marine fish. However, this method exhibits several disadvantages, including low efficiency and serious waste generation, which makes it difficult to meet the current market demand. With the rapid development of synthetic biology and the deepening of high-density fermentation technology, the collagen preparation by biosynthesis strategy emerges as the times require. Co-expression with the proline hydroxylase gene can solve the problem of non-hydroxylated collagen, but the yield may be affected. Therefore, improving the expression through molecular modification and dynamic regulation of synthesis is an entry point for future research. Due to the defects in certain properties of the natural collagen, modification of properties would be benefit for meeting the requirements of practical application. In this paper, in-depth investigations on recombinant expression, fermentation, and modification studies of collagen are conducted. Also, it summarizes the research progress of collagen in food, medicine, and beauty industry in recent years. Furthermore, the future development trend and application prospect of collagen are discussed, which would provide guidance for its preparation and application. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a progressive histological manifestation that happens in almost all chronic liver diseases. An unabated liver fibrosis may eventually develop into liver cirrhosis or hepatocellular carcinoma. Yet, the strategy for reversal of liver fibrosis is still limited. Herein, a biomimetic nano‐regulator (P‐ZIF8‐cirDNAzyme) is developed to affect both collagen synthesis and degradation in liver to remodel collagen microenvironment. It is found that Zn (II) interference can efficiently inhibit collagen synthesis in activated hepatic stellate cells (aHSC) by inactivating proline 4 hydroxylase and affecting many fibrosis‐related signaling pathways. Meanwhile, Zn (II)‐dependent circular DNAzymes (cirDNAzymes) are used to efficiently silence tissue inhibitors of metalloproteinase‐1, accelerating the degradation of collagen. They act in concert to recover the balance between collagen deposition and degradation. Additionally, ZIF‐8‐cirDNAzyme is coated by platelet membrane (PM) for precisely targeting aHSC via PM's inflammatory tropism and CD62p–CD44 interaction. In carbon tetrachloride‐induced fibrotic mice, P‐ZIF‐8‐cirDNAzyme shows a potent anti‐fibrotic effect, greatly reducing the expression of collagen by 73.12% and restoring liver function nearly to normal. This work proposes a prospective platform enabling ion interference and gene silencing, collectively acting in aHSC for reversal of liver fibrosis. [ABSTRACT FROM AUTHOR]

Astrocytes play a key role in brain functioning by providing energy to neurons. Increased astrocytic mitochondrial functions by Korean red ginseng extract (KRGE) have been investigated in previous studies. KRGE administration induces hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in astrocytes in the adult mouse brain cortex. VEGF expression can be controlled by transcription factors, such as the HIF-1α and estrogen-related receptor α (ERRα). However, the expression of ERRα is unchanged by KRGE in astrocytes of the mouse brain cortex. Instead, sirtuin 3 (SIRT3) expression is induced by KRGE in astrocytes. SIRT3 is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase that resides in the mitochondria and maintains mitochondrial homeostasis. Mitochondrial maintenance requires oxygen, and active mitochondria enhance oxygen consumption, resulting in hypoxia. The effects of SIRT3 on HIF-1α-mediated mitochondria functions induced by KRGE are not well established. We aimed to investigate the relationship between SIRT3 and HIF-1α in KRGE-treated normoxic astrocyte cells. Without changing the expression of the ERRα, small interfering ribonucleic acid targeted for SIRT3 in astrocytes substantially lowers the amount of KRGE-induced HIF-1α proteins. Reduced proline hydroxylase 2 (PHD2) expression restores HIF-1α protein levels in SIRT3-depleted astrocytes in normoxic cells treated with KRGE. The translocation of outer mitochondrial membranes 22 (Tom22) and Tom20 is controlled by the SIRT3-HIF-1α axis, which is activated by KRGE. KRGE-induced Tom22 increased oxygen consumption and mitochondrial membrane potential, as well as HIF-1α stability through PHD2. Taken together, in normoxic astrocytes, KRGE-induced SIRT3 activated the Tom22–HIF-1α circuit by increasing oxygen consumption in an ERRα-independent manner. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hypoxia-inducible factor-proline hydroxylase inhibitors (HIF-PHIs) are an emerging approach in the treatment of erythropoietin (EPO) deficiency among chronic kidney disease (CKD) patients with anaemia. Based on our previous trial of roxadustat treatment in CKD patients with anaemia [[2]], we examined the effect of roxadustat on the change in levels of FGF23 and the associated mineral parameters in patients undergoing peritoneal dialysis (PD). Erythropoietin and a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHDi) lowers FGF23 in a model of chronic kidney disease (CKD). [Extracted from the article]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chengcheng Zhu,1 Huafeng Ding,1 Junwen Yang,1 Yihui Zhou,1 Yonghong Luo,1 Suhua Shi,1 Ying Zhang,1 Yalan Wei,2 Guantai Ni1 1Departments of Gynecology and Obstetrics, Yi Jishan General Hospital of Wannan Medical College, Wuhu, Anhui, People’s Republic of China; 2Departments of Gynecology and Obstetrics, General Hospital of Wuhu Second People’s Hospital, Wuhu, Anhui, People’s Republic of ChinaCorrespondence: Guantai Ni; Yalan WeiDepartments of Gynecology and Obstetrics, Yi Jishan General Hospital of Wannan Medical College, 2 Zheshan West Road, Wuhu, Anhui 241000, People’s Republic of ChinaTel +86-138 5532 0259Email 12sunhl14@163.com; 603329457@qq.comIntroduction: Proline hydroxylase 2 (PHD2) is involved in tumorigenesis. This study aimed to examine PHD2 and hypoxia-inducible factor 1α (HIF-1α) expression in different endometrial tissues and explore the correlations between PHD2 and HIF-1α expression with clinicopathological characteristics of endometrial cancer.Methods: We collected 50 tissue sections of endometrial adenocarcinoma, 30 of atypical endometrial hyperplasia, and 30 of control normal endometrium. The expression of PHD2 was detected by PCR, Western blot, and immunohistochemical analysis.Results: PHD2 mRNA and protein levels reduced in endometrial cancer tissues compared to normal endometrium (p

Nonalcoholic fatty liver disease (NAFLD) is becoming a major health issue as obesity increases around the world. We studied the effect of a circadian locomotor output cycles kaput (CLOCK) mutant (ClkΔ19/Δ19) protein on hepatic lipid metabolism in C57BL/6 Clkwt/wt and apolipoprotein E-deficient (Apoe-/-) mice. Both ClkΔ19/Δ19 and ClkΔ19/Δ19 Apoe-/- mice developed a full spectrum of liver diseases (steatosis, steatohepatitis, cirrhosis, and hepatocellular carcinoma) recognized in human NAFLD when challenged with a Western diet, lipopolysaccharide, or CoCl2. We identified induction of CD36 and hypoxia-inducible factor 1α (HIF1α) proteins as contributing factors for NAFLD. Mechanistic studies showed that WT CLOCK protein interacted with the E-box enhancer elements in the promoters of the proline hydroxylase domain (PHD) proteins to increase expression. In ClkΔ19/Δ19 mice, PHD levels were low, and HIF1α protein levels were increased. When its levels were high, HIF1α interacted with the Cd36 promoter to augment expression and enhance fatty acid uptake. Thus, these studies establish a regulatory link among circadian rhythms, hypoxia response, fatty acid uptake, and NAFLD. The mouse models described here may be useful for further mechanistic studies in the progression of liver diseases and in the discovery of drugs for the treatment of these disorders. [ABSTRACT FROM AUTHOR]

Hydroxyproline is an industrially important compound with applications in the pharmaceutical, nutrition, and cosmetic industries. trans-4-Hydroxy-l-proline is recognized as the most abundant of the eight possible isomers (hydroxy group at C-3 or C-4, cis- or trans-configuration, and l- or d-form). However, little attention has been paid to the rare isomers, probably due to their limited availability. This mini-review provides an overview of recent advances in microbial and enzymatic processes to develop practical production strategies for various hydroxyprolines. Here, we introduce three screening strategies, namely, activity-, sequence-, and metabolite-based approaches, allowing identification of diverse proline-hydroxylating enzymes with different product specificities. All naturally occurring hydroxyproline isomers can be produced by using suitable hydroxylases in a highly regio- and stereo-selective manner. Furthermore, crystal structures of relevant hydroxylases provide much insight into their functional roles. Since hydroxylases acting on free l-proline belong to the 2-oxoglutarate-dependent dioxygenase superfamily, cellular metabolism of Escherichia coli coupled with a hydroxylase is a valuable source of 2-oxoglutarate, which is indispensable as a co-substrate in l-proline hydroxylation. Further, microbial hydroxyproline 2-epimerase may serve as a highly adaptable tool to convert l-hydroxyproline into d-hydroxyproline. Key points: • Proline hydroxylases serve as powerful tools for selectivel-proline hydroxylation. • Engineered Escherichia coli are a robust platform for hydroxyproline production. • Hydroxyproline epimerase convertsl-hydroxyproline intod-hydroxyproline. [ABSTRACT FROM AUTHOR]

Ruditapes philippinarum , is an economically and scientifically important bivalve mollusk. Its tolerance of aerial exposure has long been considered an important trait for its survival under acute environmental stress. In this study, the effects of air exposure at high and low temperatures (28 and 4°C) on the survival, antioxidant and metabolic enzyme activities, and the expression of antioxidant and immune-related genes in R. philippinarum were investigated. The activities of antioxidant and metabolic enzymes [superoxide dismutase (SOD), α-amylase, and proline hydroxylase (PHD)] were significantly affected by aerial exposure and reimmersion (reoxygenation) at both low (4°C) and high (28°C) temperatures. Moreover, the mRNA expression of α-amylase, SOD, and C-type lectin was also examined, which reveals these genes were significantly affected by aerial exposure challenge. In addition, the effects of aerial exposure and reimmersion on survival rate were calculated to evaluate the recovery capacity of Manila clam after aerial exposure at high and low temperatures. All individuals survived under low temperature aerial exposure for 24 h and reimmersion for 120 h. However, individuals died after reimmersion for 12 h following high temperature aerial exposure, and mortality peak occurred at 48 h. These data indicate that long-term aerial exposure during the transportation of clams should be in a low temperature environment. This study demonstrates that enzyme expression and activities linked to the stress response increase during the aerial exposure of R. philippinarum and provide useful information for future work on the molecular basis of tolerance of aerial exposure stress. [ABSTRACT FROM AUTHOR]

• trans -3-Hyp was firstly bioproduced from glucose with high titer and purity. • UbP3H showed high activity and selectivity for producing trans -3-Hyp. • UbP3H-Da-E112 P mutant dramatically inverted enzyme regioselectivity. • Structure basis for proline hydroxylase' regioselectivity was identified. Hydroxyprolines (Hyp) are valuable building blocks for important pharmaceuticals like carbapenem antibiotics. To date, one of four possible stable L-Hyp isomers, trans -3-Hyp, has not been specifically produced by microbial hydroxylation of L-proline, which is due to the absence of regio- and stereo-specific trans -proline 3-hydroxylases (trans -P3Hs). Here, we report the efficient bioproduction of trans -3-Hyp (˜30 g/L, 0.74 g/L/h and 0.104 g/g glucose) at an 82% (w/w) proportion by fed-batch fermentation from glucose using an engineered E. coli strain. This isolate expressed a bacterial trans -P3H from an uncultured bacterium esnapd13 (UbP3H). UbP3H exhibited a 1.6-fold and 2.6-fold increase in activity (566.2 vs. 362 U/mg) and proportion of trans -3-Hyp (85% vs. 33%, w/w) when compared with reported fungal L-proline hydroxylase (PH) from Aspergillus pachycristatus (HtyE), respectively. The trans -3-Hyp proportions for UbP3H at different temperatures (25, 37 and 45 °C) and pH buffers (6.5 and 8.0) remained largely unchanged. Additionally, the substrate specificity of UbP3H was different when compared to HtyE. Next, we elucidated the structural basis behind the high trans -3-selectivity of UbP3H towards L-proline by analyzing UbP3H and its three mutants (UbP3H-Da, E112 P and UbP3H-Da-E112 P). The results show that the engineering of loops near an active site seems to be an effective method to alter the regioselectivity of enzymes, specifically in the Fe(II)/α-ketoglutarate-dependent dioxygenase family. [ABSTRACT FROM AUTHOR]

Abstract Deferoxamine (DFO) possesses a good chelating capability and is therefore used for the clinical treatment of ion deposition diseases. Increasing evidence shows that DFO can inhibit the activity of proline hydroxylase (PHD) by chelating iron, resulting in hypoxia-induced factor (HIF) signaling activation and angiogenesis promotion. However, clinical evidence indicates that a high concentration of DFO could be biotoxic due to its enrichment in related organs. Thus, we established a new compound by conjugating DFO with the bone-seeking agent iminodiacetic acid (IDA); the new agent is called SF-DFO, and we verified its promotion of HIF activation and tube formation in vivo. After confirming the bone-seeking property of SF-DFO in the femur and vertebra of both male and female mice and comparing it to that of DFO, we analyzed the protective effect of DFO and SF-DFO in an ovariectomized (OVX) mouse model. The serum CTX-I level revealed no influence of DFO and SF-DFO on osteoclast activity, but the blood vessels and osteoblasts in the metaphysis were more abundant after SF-DFO treatment, which resulted in a greater protective effect against trabecular bone loss compared to the DFO group. Additionally, the cortical parameters and bone strength performance were identical between the DFO and SF-DFO groups. However, the diffuse inflammatory response in the liver and spleen that occurred after DFO injection was not observed in the SF-DFO group. Thus, with reduced biotoxicity and an equivalent bone-seeking capability, SF-DFO may be a better choice for the prevention of vascular degradation-induced osteoporosis. Graphical abstract Unlabelled Image Highlights • A novel bone-seeking angiogenic drug is established for promoting osteogenesis. • SF-DFO has identical hypoxia-inducing and angiogenesis-promoting effects compare to DFO. • SF-DFO has more protective effect against trabecular bone loss compared to DFO. • SF-DFO has reduced bio-toxicities compared to DFO. [ABSTRACT FROM AUTHOR]

Colon cancer is the second most lethal malignancy worldwide. A better understanding of colon cancer at the molecular level may increase overall survival rates. Previous studies have indicated that prolyl 4-hydroxylase, β polypeptide (P4HB) is associated with tumorigenesis in colon cancer; however, its role and molecular mechanisms in colon cancer remain unclear. In the present study, the cellular responses to P4HB in human colon cancer cell lines were investigated by proliferation and apoptosis assays, western blotting, and immunohistochemistry. The results showed that expression of P4HB was higher in colon cancer tissues compared within adjacent normal tissues. P4HB knockdown increased the apoptosis of human HT29 cells. Furthermore, P4HB knockdown reduced the activation of signal transducer and activator of transcription 3 (STAT3) and promoted accumulation of reactive oxygen species (ROS). Inhibiting the accumulation of ROS abrogated the increased cell apoptosis induced by P4HB knockdown. Notably, decreased ROS levels effectively antagonized the effects of P4HB on STAT3 inactivation. In conclusion, these findings suggested that P4HB knockdown may induce HT29 human colon cancer cell apoptosis through the generation of ROS and inactivation of the STAT3 signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract Hypoxia-inducible factor prolyl hydroxylases (PHDs) inhibitor stabilizes hypoxia inducible factor alpha, which increases erythropoietin (EPO) expression via the hypoxia response element. Therefore, PHDs inhibitors have been developed as novel therapeutic agents for anemia. Here, we characterize the in vitro and in vivo pharmacological profiles of TP0463518, 2-[[1-[[6-(4-chlorophenoxy)pyridin-3-yl]methyl]−4-hydroxy-6-oxo-2,3-dihydropyridine-5-carbonyl]amino]acetic acid, a novel potent PHDs inhibitor. TP0463518 competitively inhibited human PHD2 with a Ki value of 5.3 nM. TP0463518 also inhibited human PHD1/3 with IC 50 values of 18 and 63 nM as well as monkey PHD2 with an IC 50 value of 22 nM. In normal mice and rats, TP0463518 significantly increased the serum EPO levels at doses of 5 and 20 mg/kg, respectively. The correlation factors for serum EPO and the serum TP0463518 levels were 0.95 in mice and 0.92 in rats. TP0463518 also increased the serum EPO level in 5/6 nephrectomized chronic kidney disease model rats at a dose of 10 mg/kg, with a correlation factor for serum EPO and the serum TP0463518 levels of 0.82. Finally, the effect of TP0463518 in monkeys was investigated. TP0463518 was promptly removed with a half-life of 5.2 h and increased the area under the curve (AUC) of EPO at a dose of 5 mg/kg. The EPO and TP0463518 levels were also correlated. These results suggest that TP0463518 induces endogenous EPO with a strong pharmacokinetic-pharmacodynamic correlation and may contribute to desirable hemoglobin control in patients with renal anemia. [ABSTRACT FROM AUTHOR]

Highlights • Hypoxia-induced HIF-1α promotes tumor cell survival in hypoxic environment. • HIF-1α-guided abrupt metabolism disturbs the pH in the tumor microenvironment. • Acidic pH in the tumor microenvironment favors fatty acid synthesis in tumor cells. • PHD2 causes degradation of HIF-1α and reverts back all its effects. Hypoxia-inducible factor-1α (HIF-1α) shifts the metabolism of glucose from highly efficient oxidative phosphorylation to less efficient glycolysis. Pyruvic acid thus accumulated is oxidized to lactic acid which is pumped out in the tumor microenvironment. Protons generated from the pentose phosphate pathway (PPP) and upon hydrolysis of ATP further enhance the acidity in the tumor microenvironment. The resultant pH in the tumor microenvironment activates an endoplasmic reticulum protein: sterol regulatory element binding protein-1c (SREBP-1c), which once activated enhances proliferation of the tumor cell. Prolyl hydroxylase 2 (PHD2) is a negative regulator of HIF-1α and causes degradation of HIF-1α in the presence of oxygen. Chemical activation of PHD2 can downregulate HIF-1α and thus restore all its effects. The present review is an attempt to describe PHD2 as the target to combat cancer hypoxia and consequential cellular and metabolic alterations. [ABSTRACT FROM AUTHOR]

Abstract The dissociation constant p K a of the Roxadustat with UV-VIS spectra, molar absorption coefficients and protonation equilibria are the key physicochemical parameters influencing many biopharmaceutical characteristics. Roxadustat is an orally bioavailable, hypoxia-inducible factor prolyl hydroxylase inhibitor with potential anti-anemic activity. It belongs to Active Pharmacenutical Ingredients, which have acidic/basic functionalities, their ionization state is controlled by solution pH and acid dissociation constants. Nonlinear regression of the pH-spectra with programs REACTLAB and SQUAD84 and of the pH-titration curve with ESAB determined four multiple consecutive dissociation constants with the protonation scheme. A sparingly soluble neutral molecule LH 3 of Roxadustat was dissociated to the soluble anions LH 2 −, LH2− and L3− or protonated to the cation LH 4 + in an aqueous medium. The graph of molar absorption coefficients of variously protonated species according to wavelength shows that the spectra of two anions LH 2 − and LH2− are nearly the same in colour. The Roxadustat spectrum exhibited five sharp isosbestic points, which were related to the LH2−/L3− equilibrium. Four consecutive thermodynamic dissociation constants were estimated using UV-metric data p K T a1 = 3.60(04), p K T a2 = 5.62(14), p K T a3 = 7.66(16), p K T a4 = 9.08(02) at 25 °C and p K T a1 = 3.60(04), p K T a2 = 5.73(10), p K T a3 = 7.52(10), p K T a4 = 8.99(02) at 37 °C and using pH-metric data p K T a1 = 4.33(09), p K T a2 = 6.57(11), p K T a3 = 8.88(05), p K T a4 = 9.03(04) at 25 °C and p K T a1 = 4.25(09), p K T a2 = 6.49(10), p K T a3 = 8.80(06), p K T a4 = 9.00(05) at 37 °C The positive values of the enthalpy Δ H 0 showed that the dissociation process is endothermic and the positive values of the Gibbs free energy Δ G 0 at 25 °C indicated that the dissociation process was not spontaneous, which also was confirmed by a negative value of the entropy Δ S 0. Four macro-dissociation constants of Roxadustat and six protonation locations were predicted by MARVIN. Graphical abstract Unlabelled Image Highlights • Protonation equilibria studied with UV-metric and pH-metric titration analysis • Four close p K T a1 , p K T a2 , p K T a3 , p K T a4 determined at 25 °C and 37 °C in an aqueous medium • The number of protonated species estimated from the rank of UV-absorbance matrix • The Δ H 0, Δ G 0 and Δ S 0 prove the dissociation is endothermic and not spontaneous. [ABSTRACT FROM AUTHOR]

trans -4-Hydroxy- l -proline (trans -4Hyp) is widely used as a valuable building block for the organic synthesis of many pharmaceuticals such as carbapenem antibiotics. The major limitation for industrial bioproduction of trans -4Hyp is the low titer and productivity by using the existing trans -proline 4-hydroxylases (trans -P4Hs). Herein, three new trans -P4Hs from Alteromonas mediterranea (AlP4H), Micromonospora sp. CNB394 (MiP4H) and Sorangium cellulosum (ScP4H) were discovered through genome mining and enzymatic determination. These trans -P4Hs were introduced into an l -proline-producing chassis cell, and the recombinant strain overexpressing AlP4H produced the highest concentration of trans -4Hyp (3.57 g/L) from glucose in a shake flask. In a fed-batch fermentation with a 5 L bioreactor, the best strain SEcH (pTc- B74A - alp4h) accumulated 45.83 g/L of trans -4Hyp within 36 h, with the highest productivity (1.27 g/L/h) in trans -4Hyp fermentation from glucose, to the best of our knowledge. This study provides a promising hydroxylase candidate for efficient industrial production of trans -4Hyp. [ABSTRACT FROM AUTHOR]

An intriguing structural feature of echinocandins is the incorporation of hydroxylated amino acids. Elucidation of the machinery and the mechanism responsible for this modification is critical to generate new echinocandin derivatives with enhanced antifungal activity. In our present study, we biochemically characterized the α-ketoglutarate/Fe2+-dependent proline hydroxylase (HtyE) from two Aspergillus species, Aspergillus pachycristatus and Aspergillus aculeatus, in the respective echinocandin B and aculeacin A biosynthetic gene clusters. Our results showed that both Ap- and Aa-HtyE converted L-proline to trans-4- and trans-3-hydroxyproline, but at different ratios. Both enzymes also effectively hydroxylated C-3 of 4R-methyl-proline, L-pipecolic acid, and D-proline. Our homology modeling and site-directed mutagenesis studies identified Leu182 of Ap-HtyE as a key residue in determining the regioselectivity of Ap-HtyE. Notably, we found that the efficiency in C-3 hydroxylation of 4R-methyl-proline has no direct correlation with the ratio of trans-4-hydroxylproline to trans-3-hydroxylproline catalyzed by HtyE. Deletion of Ap-htyE abolished A. pachycristatus anti-Candida activity and the production of echinocandin B, demonstrating that HtyE is the enzyme responsible for the hydroxylation of L-proline and 4R-methyl-proline in vivo and is essential for the anti-Candida activity of echinocandin B. Our present study thus sheds light on the biochemical basis for the selective hydroxylation of L-proline and 4R-methyl-proline and reveals a new type of biocatalyst with potential for the custom production of hydroxylated proline and pipecolic acid derivatives. [ABSTRACT FROM AUTHOR]

Prolyl hydroxylase domain-containing protein (PHD) inhibitors are useful as orally administered agents for the treatment of renal anemia. Based on the common structures of known PHD inhibitors, we found novel PHD inhibitor 1 with a 2-[(4-hydroxy-6-oxo-2,3-dihydro-1 H -pyridine-5-carbonyl)amino]acetic acid motif. The PHD2-inhibitory activity, lipophilicity (CLogP), and PK profiles (hepatocyte metabolism, protein binding, and/or elimination half-life) of this inhibitor were used as the evaluation index to optimize the structure and eventually discovered clinical candidate 42 as the suitable compound. Compound 42 was demonstrated to promote the production of erythropoietin (EPO) following oral administration in mice and rats. The predicted half-life of this compound in humans was 1.3–5.6 h, therefore, this drug may be expected to administer once daily with few adverse effects caused by excessive EPO production. [ABSTRACT FROM AUTHOR]

Background:PLOD1 (procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1) is important for extracellular matrix formation and is involved in various diseases, including cancer; however, its role in gastrointestinal cancer is unclear. In this study, the expression of PLOD1 in gastrointestinal carcinoma and its relationships with patient survival were examined. Materials and Methods: Sample expression profiles were downloaded from the Gene Expression Omnibus database and methylation data were obtained from the Cancer Genome Atlas. Correlations between PLOD1 expression and clinicopathological features were analyzed by chi-square tests. Patient survival was evaluated by a Kaplan–Meier analysis. Results:PLOD1 expression was upregulated in gastric cancer and colorectal cancer compared with that in normal tissues. High PLOD1 levels indicated a poor prognosis. The high methylation group had a significantly lower level of PLOD1 expression. Conclusion: These results indicated that PLOD1 is highly expressed in gastrointestinal carcinoma and is a potential prognostic marker and therapeutic target. The data also indicate that hypomethylation contributes to PLOD1 upregulation in gastric and colon cancers. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the molecular mechanisms underlying the protective effects of hypoxia-inducible factor (HIF) signaling pathway activation in cardiomyocytes under anoxia-reoxygenation (A/R) injury. In this study, rat neonatal cardiomyocytes were pretreated with anti- Hif3A/Hif-3α siRNA or HIF-prolyl hydroxylase inhibitor prior to A/R injury. Our results showed that both HIF3A silencing and HIF-prolyl hydroxylase inhibition effectively increased the cell viability during A/R, led to changes in mRNA expression of HIF1-target genes, and reduced the loss of mitochondrial membrane potential (Δψ m ). Furthermore, application of anti- Hif3a siRNA led to an increase in mRNA expression of Epo , Igf1 , Slc2a1/Glut-1 , and Slc2a4/Glut-4 . Similar results were observed with HIF-prolyl hydroxylase inhibition, which additionally upregulated the mRNA expression of Epor , Tert , and Pdk1 . Hif3a RNA-interference and application of HIF-prolyl hydroxylase inhibitor during A/R modelling led to an increase of Δψ m on 11.5 and 11.9 mV respectively, compared to the control groups. Thus, Hif3a RNA interference and HIF-prolyl hydroxylase inhibition protect cardiomyocytes against A/R injury via the HIF signaling pathway. [ABSTRACT FROM AUTHOR]

Hypoxia-inducible factor 1 (HIF-1) is a key player in cellular response to hypoxia. The stability and transcriptional activity of this protein are oxygen-dependently regulated by the prolyl hydroxylases PHD1-3 and the asparaginyl hydroxylase FIH. Recently, ferritin heavy chain (FTH1) has been characterized to reinforce the HIF-1 signaling pathway in an indirect way through the inhibition of PHD activity by depleting the free iron pool in the cytoplasm. In the present study, we addressed the role of FTH1 in the FIH control of HIF-1 activity. Unexpectedly, immunoprecipitation analyses revealed that FTH1 directly interacted with FIH. In an in vitro hydroxylation assay, FTH1 was found to facilitate the FIH-mediated Asn803 hydroxylation in HIF-1α. As expected, FTH1 prevented the recruitment of p300 to HIF-1α through the Asn803 hydroxylation. In luciferase reporter analyses, FTH1 was found to repress the transcriptional activity of HIF-1α in HCT116 cells under either normoxic or hypoxic conditions. Consequently, FTH1 downregulated the expression of the HIF-1 target genes, such as VEGF, CA9 and GLUT1. Our results suggest a new role of FTH1 as a co-regulator for the FIH-mediated oxygen sensing pathway. Since HIF-1α is involved in pathogenesis of diverse hypoxia-associated diseases, we propose that FTH1 be a potential target in developing new therapeutic strategies against such diseases. [ABSTRACT FROM AUTHOR]

Echinocandins are antifungal nonribosomal hexapeptides produced by fungi. Two of the amino acids are hydroxy-L-prolines: trans-4-hydroxy-L-proline and, in most echinocandin structures, (trans-2,3)-3-hydroxy-(trans-2,4)-4-methyl-Lproline. In the case of echinocandin biosynthesis by Glarea lozoyensis, both amino acids are found in pneumocandin A0, while in pneumocandin B0 the latter residue is replaced by trans-3-hydroxy-L-proline (3-Hyp). We have recently reported that all three amino acids are generated by the 2-oxoglutarate-dependent proline hydroxylase GloF. In echinocandin B biosynthesis by Aspergillus species, 3-Hyp derivatives have not been reported. Here we describe the heterologous production and kinetic characterization of HtyE, the 2-oxoglutarate-dependent proline hydroxylase from the echinocandin B biosynthetic cluster in Aspergillus pachycristatus. Surprisingly, L-proline hydroxylation with HtyE resulted in an even higher proportion (~30%) of 3-Hyp than that with GloF. This suggests that the selectivity for methylated 3-Hyp in echinocandin B biosynthesis is due solely to a substrate-specific adenylation domain of the nonribosomal peptide synthetase. Moreover, we observed that one product of HtyE catalysis, 3-hydroxy-4-methyl-L-proline, is slowly further oxidized at the methyl group, giving 3-hydroxy-4-hydroxymethyl-Lproline, upon prolonged incubation with HtyE. This dihydroxylated amino acid has been reported as a building block of cryptocandin, an echinocandin produced by Cryptosporiopsis. IMPORTANCE Secondary metabolites from bacteria and fungi are often produced by sets of biosynthetic enzymes encoded in distinct gene clusters. Usually, each enzyme catalyzes one biosynthetic step, but multiple reactions are also possible. Pneumocandins A0 and B0 are produced by the fungus Glarea lozoyensis. They belong to the echinocandin family, a group of nonribosomal cyclic lipopeptides that exhibit a strong antifungal activity. Chemical derivatives are important drugs for the treatment of systemic fungal infections. We have recently shown that in the biosynthesis of pneumocandins A0 and B0, three hydroxyproline building blocks are provided by one proline hydroxylase. Here we demonstrate that the proline hydroxylase from echinocandin B biosynthesis in Aspergillus pachycristatus produces the same hydroxyprolines, with an increased proportion of trans-3-hydroxyproline. However, echinocandin B biosynthesis does not require trans-3-hydroxyproline; its formation remains cryptic. While one can only speculate on the evolutionary background of this unexpected finding, proline hydroxylation in G. lozoyensis and A. pachycristatus provides an unusual insight into peptide antibiotic biosynthesis--namely, the complex interplay between the selectivity of a hydroxylase and the substrate specificity of a nonribosomal peptide synthetase. [ABSTRACT FROM AUTHOR]

Prolyl hydroxylation of hypoxia inducible factor (HIF)-α, as catalysed by the Fe(ii)/2-oxoglutarate (2OG)-dependent prolyl hydroxylase domain (PHD) enzymes, has a hypoxia sensing role in animals. We report that binding of prolyl-hydroxylated HIF-α to PHD2 is ∼50 fold hindered by prior 2OG binding; thus, when 2OG is limiting, HIF-α degradation might be inhibited by PHD binding. [ABSTRACT FROM AUTHOR]

B-cell lymphomas are heterogeneous blood disorderswith limited therapeutic options, largely because of their propensity to relapse and become refractory to treatments. Carabin, a key suppressor of B-cell receptor signaling and proliferation, is inactivated in B-cell lymphoma by unknown mechanisms. Here, we identify prolyl 4-hydroxylase 2 (P4HA2) as a specific proline hydroxylase of Carabin. Carabin hydroxylation leads to its proteasomal degradation, thereby activating the Ras/extracellular signal-regulated kinase pathway and increasing B-cell lymphoma proliferation. P4HA2 is undetectable in normal B cells but upregulated in the diffuse large B-cell lymphoma (DLBCL), driving Carabin inactivation and lymphoma proliferation. Our results indicate that P4HA2 is a potential prognosis marker for DLBCL and a promising pharmacological target for developing treatment of molecularly stratified B-cell lymphomas. [ABSTRACT FROM AUTHOR]

1. ZYAN1 is a prolyl hydroxylase inhibitor in clinical development for treatment of anemia associated with chronic kidney disease (CKD). We evaluated the effect of acute and chronic kidney impairment on the pharmacokinetics of ZYAN1 in rat models. 2. Cisplatin (2.5, 5 and 7.5 mg/kg) was used to induce acute kidney injury (AKI), and five-sixth and total nephrectomy was used to induce chronic kidney injury (CKI) in male Wistar rats. All groups received a single 15 mg/kg oral dose of ZYAN1. Blood/urine samples were analyzed for ZYAN1 to assess peak concentration (Cmax), area under the concentration–time curve (AUCinf), total body clearance (CL/F) and elimination half-life (T1/2). 3. Cmaxand AUCinfwere not significantly different in the various AKI groups or in five-sixth nephrectomized rats, as compared to control rats. Recovery of ZYAN1 in urine was reduced; the impact on the CL/F was minimal. There was a 2-fold increase in AUCinfwith reduction in CL/F in total nephrectomized rats. T1/2was longer for ZYAN1 in the severe AKI/five-sixth nephrectomy rats and total nephrectomy rats as compared to control rats. 4. Based on the rodent data it may be inferred that PK of ZYAN1 in CKD patients may be minimally affected. [ABSTRACT FROM AUTHOR]

Objective: This phase I study of ZYAN1 was conducted to evaluate the safety, tolerability, and pharmacokinetics following oral administration in healthy volunteers.Methods: The study was a randomized, double-blind, placebo-controlled phase I study carried out in two parts in addition to a third part involving an open-label study to evaluate the food/sex effect. A total of 100 subjects were enrolled into the study as follows: part I-single-dose study with ZYAN1 10, 25, 50, 100, 150, 200, and 300 mg (n = 56); part II-multiple-dose study with every other day dosing of ZYAN1 100, 150, 200, and 300 mg (n = 32); and part III-sex and food effect study with ZYAN1 150 mg (n = 12; open-label).Results: ZYAN1 was well-tolerated after single and multiple oral ascending doses. No drug-related serious adverse events were reported. Following a single ascending dose of ZYAN1, the maximum concentration (C max) ranged from 566.47 ± 163.03 to 17,858.33 ± 2899.19 ng/mL and the median time to C max (t max) was approximately 2.5 h for the studied 30-fold oral doses of ZYAN1. Regardless of single or multiple doses, mean C max and area under the concentration-time curve from time zero to time t (AUC t ) values generally showed a dose-proportional increase. The mean elimination half-life (t ½) of ZYAN1 ranged from 6.9 to 13 h with negligible accumulation. Following a single dose of ZYAN1, the mean serum erythropoietin (EPO) C max values showed dose response (i.e., 6.6 and 79.9 mIU/L for 10 and 300 mg ZYAN1 doses, respectively), while the time to mean maximal serum EPO concentrations ranged from 10 to 72 h.Conclusion: Oral single (10-300 mg) and multiple dosing (100-300 mg) of ZYAN1 in healthy subjects was found to be safe and well-tolerated. With increasing ZYAN1 dose, there was almost a proportional increase in mean C max and AUC t . The mean serum EPO concentrations showed a trend of dose response. Based on the t ½, pharmacodynamic activity, and lack of drug accumulation, a once every 2 days dosing regimen of ZYAN1 was appropriate for phase II study.Trial Registration: Australian New Zealand Clinical Trials Registry trial ID ACTRN12614001240639. [ABSTRACT FROM AUTHOR]

The protozoan parasite Trypanosoma evansi is responsible for causing Surra in a variety of mammalian hosts over a wide geographical area. In the absence of an effective vaccine and increasing resistance to current chemotherapeutic agents, peptidases from the S9 prolyl oligopeptidase family have been identified as potential drug and vaccine targets. In order to understand the function of these peptidases during infection, three null mutant clones for prolyl oligopeptidase (Δpop), prolyl oligopeptidase-like (Δpop-like) and oligopeptidase B (Δopb) were generated in T. evansi RoTat 1.2 parasites and used for infection of mice. Mice inoculated with T. evansi Δpop-like mutants were able to survive longer than other groups of mice inoculated with Δpop, Δopb mutants or wild-type parasites. The regression analysis of plasma from mice-infected over time using Δpop-like mutants showed stable levels of interleukin-10 (IL-10) (non-significant slope, P = 0·171) and declining IL-1b levels (negative slope, P = 0·04) when compared with the wild-type control that demonstrated increasing levels of IL-10 and IL- 1b (P < 0·01 for both). Further analysis using mouse spleen cells in an in vitro 24 h incubation assay revealed that the percentage of IL-10 producing CD3 positive cells display significantly lower values when incubated with Δpop-like parasites than the wild-type clone (P = 0·002). These results suggest that prolyl oligopeptidase-like peptidase may play a role in immune responses during T. evansi infections by affecting interleukin concentrations in the host. [ABSTRACT FROM AUTHOR]

Abstract: Daprodustat (GSK1278863) is a prolyl hydroxylase inhibitor in phase 3 clinical studies for the treatment of anemia associated with chronic kidney disease. This study was conducted to evaluate the effect of daprodustat on cardiac repolarization and enrolled 55 healthy adult male (29) and female (26) subjects who received single‐dose 75 and 500 mg daprodustat, 400 mg moxifloxacin, and placebo. Mean placebo‐corrected change from baseline QT interval for daprodustat showed no statistically significant increase. However, statistically significant decreases in the ΔΔQTcF were observed for both doses of daprodustat, reaching a lowest value of –2.74 milliseconds for 75 mg and –5.93 milliseconds for 500 mg daprodustat; this minor shortening effect is not considered clinically significant. The moxifloxacin group showed a statistically significant increase in the ΔΔQTcF value, reaching a maximal increase of 11.47 milliseconds at 4 hours. Forty subjects (73%) reported at least 1 adverse event, with the highest incidence with 500 mg daprodustat. This group had a higher incidence of gastrointestinal adverse events compared to the other treatment groups. These results suggest that 500 mg daprodustat was not well tolerated; however, daprodustat at 75 mg was generally well tolerated. No new safety concerns were identified in subjects who received 500 mg daprodustat. [ABSTRACT FROM AUTHOR]

The discovery that the Murphy Roths Large (MRL) mouse strain is a fully competent, epimorphic tissue regenerator, proved that the machinery of regeneration was preserved through evolution from hydra, to salamanders, to mammals. Such concepts have allowed translation of the biology of amphibians, and their ability to regenerate, to a mammalian context. We identified the ancient hypoxia-inducible factor (HIF)-1α pathway, operating through prolyl hydroxylase domain proteins (PHDs), as a central player in mouse regeneration. Thus, the possibility of targeting PHDs or other HIF-1α modifiers to effectively recreate the amphibian regenerative state has emerged. We posit that these regenerative pathways are critical in mammals. Moreover, the current approved use of PHD inhibitors in the clinic should allow fast-track translation from mouse studies to drug-based regenerative therapy in humans. [ABSTRACT FROM AUTHOR]

Plasma levels of FGF23 are increased in patients with chronic kidney disease. Beside its role in phosphate homeostasis, iron deficiency and anemia are associated with increased FGF23 plasma levels. Recently, FGF23 plasma levels were shown to be increased in mice after treatment with hypoxia inducible factor-proline hydroxylase (HIF-PH) inhibitors which are strong inducers of erythropoietin and erythropoiesis and are known to modulate iron uptake and availability. Therefore we investigated a potential context between expression of FGF23 and stimulation of erythropoiesis using a HIF-PH inhibitor and erythropoietin in rats. FGF23 plasma levels are induced at peak levels 2 h after intravenous injection of recombinant human Erythropoietin (rhEPO). Likewise induction of endogenous EPO using a HIF-PH inhibitor (BAY 85–3934) is followed by an increase of FGF23 plasma levels. In contrast to rhEPO the HIF-PH inhibitor induces lower peak levels of FGF23 applying equivalent hematopoietic doses. Bone and bone marrow were identified as sources of EPO-induced FGF23. Immediate induction of FGF23 mRNA was also detected in EPO receptor positive murine hematopoietic BAF3 cells after treatment with rhEPO but not after treatment with the HIF-PH inhibitor. Pretreatment of mice with a neutralizing anti-EPO antibody abrogated FGF23 induction by the HIF-PH inhibitor. Thus, direct impact on FGF23 expression by HIF-PH inhibition in vivo via hypoxia mimicking and modulation of iron metabolism appears unlikely. Collectively, the findings point to an EPO dependent regulation pathway of FGF23 gene expression which might be important in the context of erythropoiesis stimulating therapies in patients with renal anemia. [ABSTRACT FROM AUTHOR]

Key points Glomus cells in the carotid body (CB) and chromaffin cells in the adrenal medulla (AM) are essential for reflex cardiorespiratory adaptation to hypoxia. However, the mechanisms whereby these cells detect changes in O2 tension are poorly understood., The metabolic properties of acute O2-sensing cells have been investigated by comparing the transcriptomes of CB and AM cells, which are O2-sensitive, with superior cervical ganglion neurons, which are practically O2-insensitive., In O2-sensitive cells, we found a characteristic prolyl hydroxylase 3 down-regulation and hypoxia inducible factor 2α up-regulation, as well as overexpression of genes coding for three atypical mitochondrial electron transport subunits and pyruvate carboxylase, an enzyme that replenishes tricarboxylic acid cycle intermediates., In agreement with this observation, the inhibition of succinate dehydrogenase impairs CB acute O2 sensing. The responsiveness of peripheral chemoreceptor cells to acute hypoxia depends on a 'signature metabolic profile'., Abstract Acute O2 sensing is a fundamental property of cells in the peripheral chemoreceptors, e.g. glomus cells in the carotid body (CB) and chromaffin cells in the adrenal medulla (AM), and is necessary for adaptation to hypoxia. These cells contain O2-sensitive ion channels, which mediate membrane depolarization and transmitter release upon exposure to hypoxia. However, the mechanisms underlying the detection of changes in O2 tension by cells are still poorly understood. Recently, we suggested that CB glomus cells have specific metabolic features that favour the accumulation of reduced quinone and the production of mitochondrial NADH and reactive oxygen species during hypoxia. These signals alter membrane ion channel activity. To investigate the metabolic profile characteristic of acute O2-sensing cells, we used adult mice to compare the transcriptomes of three cell types derived from common sympathoadrenal progenitors, but exhibiting variable responsiveness to acute hypoxia: CB and AM cells, which are O2-sensitive (glomus cells > chromaffin cells), and superior cervical ganglion neurons, which are practically O2-insensitive. In the O2-sensitive cells, we found a characteristic mRNA expression pattern of prolyl hydroxylase 3/hypoxia inducible factor 2α and up-regulation of several genes, in particular three atypical mitochondrial electron transport subunits and some ion channels. In addition, we found that pyruvate carboxylase, an enzyme fundamental to tricarboxylic acid cycle anaplerosis, is overexpressed in CB glomus cells. We also observed that the inhibition of succinate dehydrogenase impairs CB acute O2 sensing. Our data suggest that responsiveness to acute hypoxia depends on a 'signature metabolic profile' in chemoreceptor cells. [ABSTRACT FROM AUTHOR]

Fully activated innate immune cells are required for effective responses to infection, but their prompt deactivation and removal are essential for limiting tissue damage. Here, we have identified a critical role for the prolyl hydroxylase enzyme Phd2 in maintaining the balance between appropriate, predominantly neutrophil-mediated pathogen clearance and resolution of the innate immune response. We demonstrate that myeloid-specific loss of Phd2 resulted in an exaggerated inflammatory response to Streptococcus pneumonia, with increases in neutrophil motility, functional capacity, and survival. These enhanced neutrophil responses were dependent upon increases in glycolytic flux and glycogen stores. Systemic administration of a HIF-prolyl hydroxylase inhibitor replicated the Phd2-deficient phenotype of delayed inflammation resolution. Together, these data identify Phd2 as the dominant HIF-hydroxylase in neutrophils under normoxic conditions and link intrinsic regulation of glycolysis and glycogen stores to the resolution of neutrophil-mediated inflammatory responses. These results demonstrate the therapeutic potential of targeting metabolic pathways in the treatment of inflammatory disease. [ABSTRACT FROM AUTHOR]

The article reports on the Anatomical Society Winter meeting held at King's College London, London 2016. The issues discussed includes understanding Enteric nervous system development and understanding disease and therapy and role of embryonic hypoxia and effect of prolylhydroxylase inhibitors and using enteric nervous system stemcells for spinal cord injury repair.

Conspectus The cell membrane, the gastrointestinal tract, and the blood-brain barrier (BBB) are good examples of biological barriers that define and protect cells and organs. They impose different levels of restriction, but they also share common features. For instance, they all display a high lipophilic character. For this reason, hydrophilic compounds, like peptides, proteins, or nucleic acids have long been considered as unable to bypass them. However, the discovery of cell-penetrating peptides (CPPs) opened a vast field of research. Nowadays, CPPs, homing peptides, and blood-brain barrier peptide shuttles (BBB-shuttles) are good examples of peptides able to target and to cross various biological barriers. CPPs are a group of peptides able to interact with the plasma membrane and enter the cell. They display some common characteristics like positively charged residues, mainly arginines, and amphipathicity. In this field, our group has been focused on the development of proline rich CPPs and in the analysis of the importance of secondary amphipathicity in the internalization process. Proline has a privileged structure being the only amino acid with a secondary amine and a cyclic side chain. These features constrain its structure and hamper the formation of H-bonds. Taking advantage of this privileged structure, three different families of proline-rich peptides have been developed, namely, a proline-rich dendrimer, the sweet arrow peptide (SAP), and a group of foldamers based on γ-peptides. The structure and the mechanism of internalization of all of them has been evaluated and analyzed. BBB-shuttles are peptides able to cross the BBB and to carry with them compounds that cannot reach the brain parenchyma unaided. These peptides take advantage of the natural transport mechanisms present at the BBB, which are divided in active and passive transport mechanisms. On the one hand, we have developed BBB-shuttles that cross the BBB by a passive transport mechanism, like diketoperazines (DKPs), (N-MePhe)n, or (PhPro)n. On the other hand, we have investigated BBB-shuttles that utilize active transport mechanisms such as SGV, THRre, or MiniAp-4. For the development of both groups, we have explored several approaches, such as the use of peptide libraries, both chemical and phage display, or hit-to-lead optimization processes. In this Account, we describe, in chronologic order, our contribution to the development of peptides able to overcome various biological barriers and our efforts to understand the mechanisms that they display. In addition, the potential use of both CPPs and BBB-shuttles to improve the transport of promising therapeutic compounds is described. [ABSTRACT FROM AUTHOR]

Investigation into the regulation of the erythropoietin gene by oxygen led to the discovery of a process of direct oxygen sensing that transduces many cellular and systemic responses to hypoxia. The oxygen-sensitive signal is generated through the catalytic action of a series of 2-oxoglutarate-dependent oxygenases that regulate the transcription factor hypoxia-inducible factor (HIF) by the post-translational hydroxylation of specific amino acid residues. Here we review the implications of the unforeseen complexity of the HIF transcriptional cascade for the physiology and pathophysiology of hypoxia, and consider the origins of post-translational hydroxylation as a signaling process. [ABSTRACT FROM AUTHOR]

The oxygen-sensitive hypoxia-inducible factor (HIF) pathway plays a central role in the control of erythropoiesis and iron metabolism. The discovery of prolyl hydroxylase domain (PHD) proteins as key regulators of HIF activity has led to the development of inhibitory compounds that are now in phase 3 clinical development for the treatment of renal anemia, a condition that is commonly found in patients with advanced chronic kidney disease. This review provides a concise overview of clinical effects associated with pharmacologic PHD inhibition and was written in memory of Professor Lorenz Poellinger. [ABSTRACT FROM AUTHOR]

Herein we describe the identification of 4-{[1,2,4]triazolo[1,5-a]pyridin-5-yl}benzonitrile-based inhibitors of the hypoxia-inducible factor prolylhydroxylase domain-1 (PHD-1) enzyme. These inhibitors were shown to possess a novel binding mode by X-ray crystallography, in which the triazolo N1 atom coordinates in a hitherto unreported monodentate interaction with the active site Fe2+ ion, while the benzonitrile group accepts a hydrogen-bonding interaction from the side chain residue of Asn315. Further optimization led to potent PHD-1 inhibitors with good physicochemical and pharmacokinetic properties. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) results in a delay in wound healing because of its complications such as uremia, anemia, and fluid overload. Mesenchymal stem cells (MSCs) are considered to be a candidate for wound healing because of the ability to recruit many types of cells. However, it is still unclear whether the CKD-adipose tissue-derived MSCs (CKD-AT-MSCs) have the same function in wound healing as healthy donor-derived normal AT-MSCs (nAT-MSCs). In this study, we found that uremic toxins induced elevated reactive oxygen species (ROS) expression in nAT-MSCs, resulting in the reduced expression of hypoxia-inducible factor-1α (HIF-1α) under hypoxic conditions. Consistent with the uremic-treated AT-MSCs, there was a definite imbalance of redox state and high expression of ROS in CKD-AT-MSCs isolated from early-stage CKD patients. In addition, a transplantation study clearly revealed that nAT-MSCs promoted the recruitment of inflammatory cells and recovery from ischemia in the mouse flap model, whereas CKD-AT-MSCs had defective functions and the wound healing process was delayed. Of note, the expression of prolyl hydroxylase domain 2 (PHD2) is selectively increased in CKD-AT-MSCs and its inhibition can restore the expression of HIF-1α and the wound healing function of CKD-AT-MSCs. These results indicate that more studies about the functions of MSCs from CKD patients are required before they can be applied in the clinical setting. [ABSTRACT FROM AUTHOR]

Hypoxia inducible factor-1 (HIF-1) is a key regulator in hypoxia and can determine the fate of brain cells during ischemia. However, the mechanism of HIF-1 regulation is still not fully understood in ischemic brains. We tested a hypothesis that both the 26S and the 20S proteasomal pathways were involved in HIF-1α degradation under ischemic conditions. Using in vitro ischemic model (oxygen and glucose deprivation) and a mouse model of middle cerebral artery occlusion, we tested effects of inhibitors of proteasomes and prolyl hydroxylase (PHD) on HIF-1α stability and brain injury in cerebral ischemia. We observed that 30 and 60min of oxygen-glucose deprivation significantly increased the 20S proteasomal activity.We demonstrated that proteasome inhibitors increased HIF-1α stabilization and cell viability and were more effective than PHD inhibitors in primary cultured cortical neurons exposed to oxygen and glucose deprivation. Furthermore, the administration of the proteasome inhibitor, epoxomicin, to mice resulted in smaller infarct size and brain edema than a PHD inhibitor. Our results indicate that 20S proteasomes are involved in HIF-1α degradation in ischemic neurons and that proteasomal inhibition provides more HIF-1α stabilization and neuroprotection than PHD inhibition in cerebral ischemia. [ABSTRACT FROM AUTHOR]

Collagen prolyl 4-hydroxylase (C-P4H), an α2β2 heterotetramer, is a crucial enzyme for collagen synthesis. The α-subunit consists of an N-terminal dimerization domain, a central peptide substrate-binding (PSB) domain, and a C-terminal catalytic (CAT) domain. The β-subunit [also known as protein disulfide isomerase (PDI)] acts as a chaperone, stabilizing the functional conformation of C-P4H. C-P4H has been studied for decades, but its structure has remained elusive. Here, we present a three-dimensional small-angle X-ray scattering model of the entire human C-P4H-I heterotetramer. C-P4H is an elongated, bilobal, symmetric molecule with a length of 290 Å. The dimerization domains from the two α-subunits form a protein-protein dimer interface, assembled around the central antiparallel coiled-coil interface of their N-terminal α-helices. This region forms a thin waist in the bilobal tetramer. The two PSB/CAT units, each complexed with a PDI/β-subunit, form two bulky lobes pointing outward from this waist region, such that the PDI/β-subunits locate at the far ends of the βααβ complex. The PDI/β-subunit interacts extensively with the CAT domain. The asymmetric shape of two truncated C-P4H-I variants, also characterized in the present study, agrees with this assembly. Furthermore, data from these truncated variants show that dimerization between the α-subunits has an important role in achieving the correct PSB-CAT assembly competent for catalytic activity. Kinetic assays with various proline-rich peptide substrates and inhibitors suggest that, in the competent assembly, the PSB domain binds to the procollagen substrate downstream from the CAT domain. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of prolyl-hydroxyproline (Pro-Hyp) on the proliferation and differentiation of rat stromal-vascular cells (SVCs) being cultured in a medium with (Pro-Hyp group) or without Pro-Hyp (control group). The results showed that there was no significant difference in proliferation rate of SVCs, lipid droplet (LD) diameter or intracellular concentration of triglycerides between two groups. However, the diameter range of LDs in the Pro-Hyp group tended to be smaller than that in the control group. Transmission electron microscopy showed a tendency for increase in the area of mitochondria and decrease in the number of mitochondria in the Pro-Hyp-treated SVCs. The mRNA expression levels of white adipose tissue differentiation markers (Cbp, Fabp and Serpina3k) were significantly lower, but those of the brown adipose tissue differentiation markers (Dio2, Ucp1 and Ucp3) were significantly higher in the Pro-Hyp group than in the control group. Our results suggested that Pro-Hyp can facilitate SVCs to differentiate into "brite/beige" adipocytes. [ABSTRACT FROM AUTHOR]

ABSTRACT Andrographolide, the main bioactive component of the medicinal plant Andrographis paniculata, has been shown to possess potent anti-inflammatory activity. Endothelin 1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, displays proinflammatory property. Hypoxia-inducible factor 1α (HIF-1α), the regulatory member of the transcription factor heterodimer HIF-1α/β, is one of the most important molecules that responds to hypoxia. Changes in cellular HIF-1α protein level are the result of altered gene transcription and protein stability, with the latter being dependent on prolyl hydroxylases (PHDs). In this study, inhibition of pro-inflammatory ET-1 expression and changes of HIF-1α gene transcription and protein stability under hypoxia by andrographolide in EA.hy926 endothelial-like cells were investigated. Hypoxic conditions were created using the hypoxia-mimetic agent CoCl2. We found that hypoxia stimulated the production of reactive oxygen species (ROS), the expression of HIF-1α mRNA and protein, and the expression and secretion of ET-1. These effects, however, were attenuated by co-exposure to andrographolide, bilirubin, and RuCO. Silencing Nrf2 and heme oxygenase 1 (HO-1) reversed the inhibitory effects of andrographolide on hypxoia-induced HIF-1α mRNA and protein expression. Moreover, andrographolide increased the expression of prolyl hydroxylases (PHD) 2/3, which hydroxylate HIF-1α and promotes HIF-1α proteasome degradation, with an increase in HIF-1α hydroxylation was noted under hypoxia. Inhibition of p38 MAPK abrogated the hypoxia-induced increases in HIF-1α mRNA and protein expression as well as ET-1 mRNA expression and secretion. Taken together, these results suggest that andrographolide suppresses hypoxia-induced pro-inflammatory ET-1 expression by activating Nrf2/HO-1, inhibiting p38 MAPK signaling, and promoting PHD2/3 expression. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 918-930, 2017. [ABSTRACT FROM AUTHOR]

Prolyl oligopeptidase (POP) is a serine endopeptidase widely distributed in vivo with high activity in the liver. However, its biological functions in the liver have remained largely elusive. A previous study by our group has shown that POP produced N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) and thereby exerted an anti-fibrogenic effect on hepatic stellate cells (HSCs) in vitro. It was therefore hypothesized that POP may affect the activation state of HSCs and has an important role in liver fibrosis. The HSC-T6 immortalized rat liver stellate cell line was treated with the POP inhibitor S17092 or transfected with recombinant lentivirus to overexpress POP. Cell proliferation and apoptosis were determined using a Cell Counting Kit-8 and flow cytometry, respectively. The activation status of HSCs was determined by examination of the expression of α-smooth muscle actin (α-SMA), collagen I, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor (TGF)-β-Smad signaling and peroxisome proliferator activated receptor-γ (PPAR-γ). Inhibition by S17092 decreased, whereas lentiviral expression increased the activity of POP and cell proliferation, while neither of the treatments affected cell apoptosis. Of note, S17092 significantly increased, whereas POP overexpression decreased the expression of α-SMA and MCP-1 without affecting the expression of collagen I and TGF-β1. Furthermore, S17092 caused a reduction, whereas POP overexpression caused an upregulation of Smad7 protein and PPAR-γ, but not phosphorylated-Smad2/3 expression. In conclusion, POP attenuated the activation of HSCs through inhibition of TGF-β signaling and induction of PPAR-γ, which may have therapeutic potential in liver fibrosis. [ABSTRACT FROM AUTHOR]