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Current treatment approaches for hyperlipidemia rely mainly on reducing the cholesterol level by inhibiting 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), which is involved in the presqualene pathway of cholesterol biosynthesis. Finding a compound that instead targets the postsqualene pathway could aid in the treatment of hyperlipidemia and synergistically reduce the cholesterol level when used in conjunction with HMGCR inhibitors. Ergosterol is a fungal sterol that is converted to brassicasterol by 7-dehydrocholesterol reductase (DHCR7). DHCR7 is also a cholesterol biosynthesis enzyme, and thus ergosterol may cause the accumulation of 7-dehydrocholesterol, a precursor of cholesterol and vitamin D

Many pharmaceuticals and dietary foods have been reported to inhibit cholesterol biosynthesis, mainly by inhibiting the presqualene enzyme 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase rather than a postsqualene enzyme. In this study, we examined the inhibitory effects of Latilactobacillus sakei UONUMA on cholesterol biosynthesis, especially postsqualene, in human HepG2 hepatoma cells. We quantified cholesterol and its precursors, and the mRNA and protein levels of enzymes involved in cholesterol biosynthesis. Three L. sakei UONUMA strains exhibited new inhibitory effects on cholesterol biosynthesis and inhibited the mRNA level of sterol-delta24-reductase (DHCR24), which is involved in the postsqualene cholesterol biosynthesis pathway. These strains will be useful for the prevention and treatment of hyperlipidemia.

OBJECTIVE IgG4-related disease (IgG4-RD) is a unique inflammatory disorder in which Th2 cytokines promote IgG4 production. In addition, recent studies have implicated the Toll-like receptor (TLR) pathway. This study was undertaken to examine the expression of TLRs in salivary glands (SGs) from patients with IgG4-RD. METHODS SGs from 15 patients with IgG4-RD, 15 patients with Sjogren's syndrome (SS), 10 patients with chronic sialadenitis, and 10 healthy controls were examined histologically. TLR family gene expression (TLR-1 through TLR-10) was analyzed by DNA microarray in the submandibular glands (SMGs). Up-regulation of TLRs was confirmed in SGs from patients with IgG4-RD. Finally, the phenotype of human TLR-7 (huTLR-7)-transgenic C57BL/6 mice was assessed before and after stimulation with TLR agonist. RESULTS In patients with IgG4-RD, TLR-4, TLR-7, TLR-8, and TLR-9 were overexpressed. Polymerase chain reaction validated the up-regulation of TLR-7 in IgG4-RD compared with the other groups. Immunohistochemical analysis confirmed strong infiltration of TLR-7-positive cells in the SGs of patients with IgG4-RD. Double immunohistochemical staining showed that TLR-7 expression colocalized with CD163+ M2 macrophages. After in vitro stimulation with a TLR-7 agonist, CD163+ M2 macrophages produced higher levels of interleukin-33 (IL-33), which is a Th2-activating cytokine. In huTLR-7-transgenic mice, the focus and fibrosis scores in SMGs, pancreas, and lungs were significantly higher than those in wild-type mice (P < 0.05). Moreover, the concentration of serum IgG, IgG1, and IL-33 in huTLR-7-transgenic mice was distinctly increased upon stimulation with a TLR-7 agonist (P < 0.05). CONCLUSION TLR-7-expressing M2 macrophages may promote the activation of Th2 immune responses via IL-33 secretion in IgG4-RD.

Many pharmaceuticals and dietary foods have been reported to inhibit cholesterol biosynthesis, mainly by inhibiting the presqualene enzyme 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase rather than a postsqualene enzyme. In this study, we examined the inhibitory effects of Latilactobacillus sakei UONUMA on cholesterol biosynthesis, especially postsqualene, in human HepG2 hepatoma cells. We quantified cholesterol and its precursors, and the mRNA and protein levels of enzymes involved in cholesterol biosynthesis. Three L. sakei UONUMA strains exhibited new inhibitory effects on cholesterol biosynthesis and inhibited the mRNA level of sterol-delta24-reductase (DHCR24), which is involved in the postsqualene cholesterol biosynthesis pathway. These strains will be useful for the prevention and treatment of hyperlipidemia.

Sesamin is a major lignan in sesame, and its biological effects such as antioxidant effect, anti-carcinogenic effects, and suppression of hypertension have been extensively studied by many researchers. However, its metabolic pathways and metabolic enzymes in human bodies have not been identified. Recently we demonstrated that CYP2C9 was the most important cytochrome P450 isoform in human liver. Next, we focused on metabolism of sesamin mono-catechol by cytochrome P450 or UDP-glucuronosyltransferase (UGT). Further catecholization of sesamin mono-catechol by cytochrome P450 enhances its anti-oxidant activity, whereas glucuronidation by UGT strongly reduces anti-oxidant activity. In human liver microsomes, glucuronidation activity toward sesamin mono-catechol was much higher than the di-catecholization activity. In contrast, both activities were similar in rat liver microsomes. These results suggest a large species-based difference between humans and rats in sesamin metabolism. In vitro studies using 10 individual human liver microsomes suggested that UGT2B7 was responsible for glucuronidation of sesamin mono-catechol in human liver. In addition, we observed a significant methylation activity toward sesamin mono-catechol by catechol O-methyl transferase (COMT) in human liver cytosol. Based on these results, we concluded that CYP2C9, UGT2B7, and COMT played essential roles in the metabolism of sesamin in human liver.

Background The mortality rate is very high for patients with severe multiple trauma with massive pulmonary contusion containing intrapulmonary hemorrhage. Multiple treatment modalities are needed not only for a prevention of cardiac arrest and quick hemostasis against multiple injuries, but also for recovery of oxygenation to save the patient’s life. Case presentation A 48-year-old Japanese woman fell down stairs that had a height of approximately 4 m. An X-ray showed pneumothorax, pulmonary contusion in her right lung, and an unstable pelvic fracture. A chest drain was inserted and preperitoneal pelvic packing was performed to control bleeding, performing resuscitative endovascular balloon occlusion of the aorta. A computed tomography scan revealed massive lung contusion in the lower lobe of her right lung, pelvic fractures, and multiple fractures and hematoma in other areas. An emergency thoracotomy was performed, and then we performed wide wedge resection of the injured lung, clamping proximal to suture lines with two Satinsky blood vessel clamps. The vessel clamps were left in the right thoracic cavity. The other hemorrhagic areas were embolized by transcatheter arterial embolization. However, since her respiratory functions deteriorated in the intensive care unit, veno-venous extracorporeal membrane oxygenation was used for lung assist. Planned reoperation under veno-venous extracorporeal membrane oxygenation was performed on day 2. Since her respiratory condition improved gradually, the veno-venous extracorporeal membrane oxygenation circuit was withdrawn on day 7. She was transferred to the psychiatric ward of our hospital on day 75. Conclusion Utilizing multiple treatment modalities such as resuscitative endovascular balloon occlusion of the aorta, damage control surgery, transcatheter arterial embolization, and veno-venous extracorporeal membrane oxygenation with appropriate timing saves a patient with severe polytrauma with massive pulmonary contusion including intrapulmonary hemorrhage.

Cognitive performance in people varies according to time-of-day, with memory retrieval declining in the late afternoon-early evening. However, functional roles of local brain circadian clocks in memory performance remains unclear. Here, we show that hippocampal clock controlled by the circadian-dependent transcription factor BMAL1 regulates time-of-day retrieval profile. Inducible transgenic dominant negative BMAL1 (dnBMAL1) expression in mouse forebrain or hippocampus disrupted retrieval of hippocampal memories at Zeitgeber Time 8–12, independently of retention delay, encoding time and Zeitgeber entrainment cue. This altered retrieval profile was associated with downregulation of hippocampal Dopamine-cAMP signaling in dnBMAL1 mice. These changes included decreases in Dopamine Receptors (D1-R and D5-R) and GluA1-S845 phosphorylation by PKA. Consistently, pharmacological activation of cAMP-signals or D1/5Rs rescued impaired retrieval in dnBMAL1 mice. Importantly, GluA1 S845A knock-in mice showed similar retrieval deficits with dnBMAL1 mice. Our findings suggest mechanisms underlying regulation of retrieval by hippocampal clock through D1/5R-cAMP-PKA-mediated GluA1 phosphorylation., The neural mechanisms that lead to a relative deficit in memory retrieval in the afternoon are unclear. Here, the authors show that the circadian - dependent transcription factor BMAL1 regulates retrieval through dopamine and glutamate receptor phosphorylation.

Our previous study revealed that the 2α-substituted vitamin D analog 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)2D3 (AH-1) exhibited a higher osteocalcin promoter transactivation activity in human osteosarcoma cells and a greater effect on bone mineral density in a rat model of osteoporosis than 1α,25(OH)2D3 without increasing blood calcium concentration. Thus, we hypothesized that AH-1 could be a promising therapeutic agent for osteoporosis without any serious side effects. In this study, we compared the CYP24A1-dependent metabolism of AH-1 with that of 1α,25(OH)2D3. The resistance to CYP24A1-dependent metabolism could be an important property of vitamin D analogs in prolonging their biological effects. A kinetic analysis was performed using a membrane fraction prepared from recombinant E. coli expressing human CYP24A1. The kcat/Km (μM-1 min-1) value for AH-1 was 31% of that for 1α,25(OH)2D3, suggesting that AH-1 is not as resistant to CYP24A1-dependent metabolism as the other C2-substituted vitamin D analogs such as eldecalcitol [2β-hydroxypropoxy-1α,25(OH)2D3]. The major metabolite of AH-1 was the 24R-hydroxylated metabolite, which had high vitamin D receptor (VDR) binding affinity and high HL-60 cell differentiation activity similar to AH-1 itself. In contrast, 1α,25(OH)2D3 was metabolized by multistep monooxygenation reactions, which led to the loss of affinity for VDR. Thus, the greater therapeutic effects of AH-1 than those of 1α,25(OH)2D3 in in vivo studies using osteoporosis rat models may be due to 24R-hydroxy-AH-1 whose VDR affinity was 91% of that of AH-1.

Cytochrome P450 enzymes belonging to the CYP105 family are predominantly found in bacteria belonging to the phylum Actinobacteria and the order Actinomycetales. In this review, we focused on the protein engineering of P450s belonging to the CYP105 family for industrial use. Two Arg substitutions to Ala of CYP105A1 enhanced its vitamin D3 25- and 1α-hydroxylation activities by 400 and 100-fold, respectively. The coupling efficiency between product formation and NADPH oxidation was largely improved by the R84A mutation. The quintuple mutant Q87W/T115A/H132L/R194W/G294D of CYP105AB3 showed a 20-fold higher activity than the wild-type enzyme. Amino acids at positions 87 and 191 were located at the substrate entrance channel, and that at position 294 was located close to the heme group. Semi-rational engineering of CYP105A3 selected the best performing mutant, T85F/T119S/V194N/N363Y, for producing pravastatin. The T119S and N363Y mutations synergistically had remarkable effects on the interaction between CYP105A3 and putidaredoxin. Although wild-type CYP105AS1 hydroxylated compactin to 6-epi-pravastatin, the quintuple mutant I95T/Q127R/A180V/L236I/A265N converted almost all compactin to pravastatin. Five amino acid substitutions by two rounds of mutagenesis almost completely changed the stereo-selectivity of CYP105AS1. These results strongly suggest that the protein engineering of CYP105 enzymes greatly increase their industrial utility. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.

Our previous studies revealed that CYP105A1 can convert vitamin D3 (VD3) to its active form, 1α,25-dihydroxyvitamin D3 (1,25D3). Site-directed mutagenesis of CYP105A1 based on its crystal structure dramatically enhanced its activity; the activity of double variants R73A/R84A and R73A/R84V was more than 100-fold higher than that of the wild type of CYP105A1. In contrast, these variants had a low ability to convert vitamin D2 (VD2) to 1α,25-dihydroxyvitamin D2 (1,25D2), whereas they catalyzed the sequential hydroxylation at positions C25 and C26 to produce 25,26D2. A comparison of the docking models of 25D2 and 25D3 into the substrate-binding pocket of R73A/R84A suggests that the side chain of the Met239 inhibits the binding of 25D2 for 1α-hydroxylation. Therefore, the Met239 residue of R73A/R84A was substituted for Ala. As expected, the triple variant R73A/R84A/M239A showed a 22-fold higher 1α-hydroxylation activity towards 25D2. To the best of our knowledge, this is the first report on the generation of microbial cytochrome P450 that converts VD2 to 1,25D2 via 25D2.

Objectives: In this study, we investigated the diagnostic utility of submandibular gland (SMG) sonography and labial salivary gland (LSG) biopsy as a less invasive procedure for diagnosing ...

ObjectivesIgG4-related disease (IgG4-RD) is a chronic, systemic, inflammatory condition of unknown aetiology. We have recently described clonally expanded circulating CD4+ cytotoxic T lymphocytes (CTLs) in IgG4-RD that infiltrate affected tissues where they secrete interleukin (IL)-1β and transforming growth factor -β1 (TGF-β1). In this study, we sought to examine the role of CD4+ CTLs in the pathogenesis of IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) and to determine whether these cells secrete interferon-gamma (IFN-γ) at lesional sites.MethodsSalivary glands of 25 patients with IgG4-DS, 22 patients with Sjögren's syndrome (SS), 12 patients with chronic sialoadenitis (CS) and 12 healthy controls were analysed in this study. Gene expression analysis was performed on submandibular glands (SMGs) from five patients with IgG4-DS, three with CS and three healthy controls. Infiltrating CD4+ CTLs were examined by quantitative multicolour imaging in tissue samples from 20 patients with IgG4-DS, 22 patients with SS, 9 patients with CS and 9 healthy controls.ResultsIn IgG4-DS tissues, nine genes associated with CD4+ CTLs were overexpressed. The expression of granzyme A (GZMA) mRNA was significantly higher in samples from patients with IgG4-RD compared with corresponding tissues from SS and healthy controls. Quantitative imaging showed that infiltrating CD4+ GZMA+ CTLs were more abundant in patients with IgG4-DS than in the other groups. The ratio of CD4+GZMA+ CTLs in SMGs from patients with IgG4-DS correlated with serum IgG4 concentrations and the number of affected organs. A large fraction of CD4+GZMA+ CTLs in SMGs from patients with IgG4-DS secreted IFN-γ.ConclusionsThe pathogenesis of IgG4-DS is associated with tissue infiltration by CD4+GZMA+ CTLs that secrete IFN-γ.

Our previous studies revealed that the double variants of CYP105A1- R73A/R84A and R73V/R84A-show high levels of activity with respect to conversion of vitamin D3 to its biologically active form, 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3). In this study, we found that both the double variants were also capable of converting vitamin D2 to its active form, that is, 1α,25-dihydroxyvitamin D2 (1α,25(OH)2D2), via 25(OH)D2, whereas its 1α-hydroxylation activity toward 25(OH)D2 was much lower than that toward 25(OH)D3. Comparison of the wild type and the double variants revealed that the amino acid substitutions remarkably enhanced both 25- and 26-hydroxylation activity toward vitamin D2. After 25-hydroxylation of vitamin D2, further hydroxylation at C26 may occur frequently without the release of 25(OH)D2 from the substrate-binding pocket. Thus, the double variants of CYP105A1 are quite useful to produce 25,26(OH)2D2 that is one of the metabolites of vitamin D2 detected in human serum.

For the definitive diagnosis of IgG4-related disease (IgG4-RD), biopsies of local lesions are recommended so as to exclude other diseases, including lymphoma and cancer. However, performing biopsies of underlying organs is technically difficult. In this study, we examined the diagnostic utility of labial salivary gland (LSG) biopsy as a less invasive procedure.Sixty-six patients with suspected IgG4-RD by clinical findings or high serum IgG4 underwent LSG biopsy. We examined the relationship between the number of IgG4-positive plasma cells in LSG and clinical findings.The final diagnosis was 45 patients with IgG4-RD, 12 with Sjögren's syndrome, four with suspected Sjögren's syndrome, three with malignant lymphoma, one with systemic lupus erythematosus, and one with Warthin's tumor. The sensitivity, specificity, and accuracy of LSG biopsy were 55.6%, 100.0%, and 70.0%, respectively. Forty-five IgG4-RD patients were divided into two groups: 1) 25 with lesions of salivary glands (IgG4-RD S+) and 2) 20 without these lesions (IgG4-RD S-). Seventeen of 25 (68.0%) IgG4-RD S + and 8 of 20 (40.0%) IgG4-RD S - patients were positive for LSG biopsy. In the IgG4-RD S - patients, the mean number of affected organs and serum IgG4 in the positive cases for LSG biopsy were significantly higher than in the negative cases.A solo LSG biopsy is insufficient for the diagnosis of IgG4-RD because of its low sensitivity. However, LSG biopsy combined with clinical findings, including serum IgG4 and number of affected organs, may contribute towards a diagnosis of IgG4-RD patients with affected underlying organs.

Distinct TFH subsets that influence specific class-switching events are assumed to exist, but the accumulation of isotype-specific TFH subsets in secondary and tertiary lymphoid organs has not been hitherto demonstrated. IL-4 expressing TFH cells are surprisingly sparse in human secondary lymphoid organs. In sharp contrast, in IgG4-related disease (IgG4-RD), a disorder characterized by polarized Ig class switching, most TFH cells in tertiary and secondary lymphoid organs make IL-4. Human IL-4+ TFH cells do not express GATA-3 but express nuclear BATF, and the transcriptomes of IL-4 secreting TFH cells differ both from PD1hi TFH cells that do not secrete IL-4 and IL4-secreting non-TFH cells. Unlike IgG4-RD, IL-4+ TFH cells are rarely found in tertiary lymphoid organs in Sjögren’s syndrome, a disorder in which IgG4 is not elevated. The proportion of CD4+IL-4+BATF+ T cells as well as of CD4+IL-4+CXCR5+ T cells in IgG4-RD tissues correlates tightly with tissue IgG4 plasma cell numbers and plasma IgG4 levels in patients but not with the total plasma levels of other isotypes. These data describe a disease-related TFH sub-population in human tertiary and secondary lymphoid organs that is linked to IgG4 class switching.

Rotational thromboelastometry (ROTEM), known as point-of-care testing, has been incorporated into various kinds of postsurgical management. However, the utility of ROTEM for rapid diagnosis of sepsis-induced disseminated intravascular coagulation (DIC) has not been investigated. This retrospective study includes 13 sepsis patients who underwent ROTEM in our emergency department in 2013. All patients were divided into two groups on the basis of the presence of DIC diagnosed by the Japanese Association for Acute Medicine (JAAM) DIC score. We evaluated the demographics, clinical characteristics, laboratory data, ROTEM test and outcomes for each patient. The correlations between JAAM DIC score and significantly different parameters by univariate analysis and receiver operating characteristic (ROC) analysis were performed to assess the accuracy of the variables. There were seven and six patients in the DIC group and non-DIC group, respectively. The DIC group showed significantly longer prothrombin times, international normalized ratio of prothrombin time and clotting times (CTs) in the EXTEM test, and higher fibrinogen and fibrin degradation products and D-dimer. The CT in EXTEM test was correlated more with JAAM DIC score (r = 0.798), than the standard coagulation test. These parameters were accurate predictors in the diagnosis of septic DIC, with an AUC of 0.952, and a cut-off value of more than 46.0 s, resulting in a sensitivity of 100.0% and a specificity of 83.3%. CT in the EXTEM test was a single reliable indicator of sepsis-induced DIC diagnosed by the JAAM DIC score, and strongly associated with severity of DIC.

Our previous study revealed that the 2α-substituted vitamin D analog 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)

Tumor-associated macrophages (TAMs) promote cancer cell proliferation, invasion, and metastasis by producing various mediators. Although preclinical studies demonstrated that TAMs preferentially express CD163 and CD204, the TAM subsets in oral squamous cell carcinoma (OSCC) remain unknown. In this study, we examined the expression and role of TAM subsets in OSCC. Forty-six patients with OSCC were analyzed for expression of TAMs in biopsy samples by immunohistochemistry. We examined TAM subsets and their production of immune suppressive molecules (IL-10 and PD-L1) in peripheral blood mononuclear cells from three OSCC patients by flow cytometry. CD163 was detected around the tumor or connective tissue, while CD204 was detected in/around the tumors. Flow cytometric analysis revealed that CD163+CD204+ TAMs strongly produced IL-10 and PD-L1 in comparison with CD163+CD204− and CD163−CD204+ TAMs. Furthermore, the number of activated CD3+ T cells after co-culture with CD163+CD204+ TAMs was significantly lower than that after co-culture with other TAM subsets. In clinical findings, the number of CD163+CD204+ TAMs was negatively correlated with that of CD25+ cells and 5-year progression-free survival. These results suggest that CD163+CD204+ TAMs possibly play a key role in the invasion and metastasis of OSCC by T-cell regulation via IL-10 and PD-L1 production.

Introduction The aim of this study was to evaluate the efficacy and complications of recombinant antithrombin (rAT) supplementation for adult patients with disseminated intravascular coagulation (DIC) compared with conventional plasma derived AT (pAT) treatment in the intensive care unit. Materials and methods This study was performed in a single national university hospital in Japan. Adult patients from April 2015 to March 2016 with DIC were divided into two groups based on the type of AT agent used: the pAT group (n = 24) and the rAT group (n = 21). Patient demographics, medical history, diagnosis, blood tests, various clinical scores, AT activity, complications, and clinical outcome were collected and analyzed retrospectively. Results Significantly higher SIRS and APACHEII scores were confirmed in the rAT group than the pAT group. The initial dose of AT was significantly higher in the rAT group than in the pAT group. ATIII values before and after initial supplementation and during their ten-day clinical course were statistically similar between two groups. During the same period, 10 bleeding adverse events were found and there was no significant difference between both groups. Significantly more cases of the rAT group were administered with recombinant thrombomodulin concomitantly than those of the pAT group. Despite significantly more severe patients in rAT group, the clinical outcomes were the same in each group. Conclusions Compared with pAT, the supplementation of rAT indicates clinical effectiveness without increasing the risk of bleeding complications in adult DIC patients with low AT activity.

Our previous studies revealed that CYP105A1 can convert vitamin D

IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by serum IgG4 elevation and the infiltration of IgG4-positive plasma cells in glandular tissues. For definitive diagnosis of IgG4-DS, biopsies of local lesions are recommended to exclude Sjögren's syndrome (SS), malignant tumours, and similar disorders. In this study, we examined the diagnostic utility of submandibular gland (SMG) and labial salivary gland (LSG) biopsies in IgG4-DS. Fourteen patients presenting with swelling of the SMG (eight females and six males) underwent both SMG and LSG biopsies. The sensitivity, specificity, and accuracy of SMG biopsies were all 100.0%. In contrast, those of LSG biopsies were 69.2%, 100.0%, and 71.4%, respectively. Thirty-three out of 61 LSG biopsies (54.1%) from all 14 patients were positive for the diagnostic criteria of IgG4-DS (IgG4-positive/IgG-positive plasma cells >0.4). None of the patients experienced complications such as facial nerve palsy, sialocele, or hyposalivation. The IgG4/IgG ratio showed no significant correlation between the LSG and SMG. The final diagnosis was IgG4-DS in 13 patients and marginal zone B-cell lymphoma (MZL) in one. These results suggest that incisional biopsy of the SMG is useful and appropriate for the definitive diagnosis of IgG4-DS, while diagnosis by LSG biopsy alone requires more caution.

Our previous studies revealed that C2α-substituted-1α,25(OH)(2)D(3) analogs had unique biological activities. For example, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (MART-10), which has a high affinity for vitamin D receptor (VDR), is more bioavailable and more potent than 1α,25(OH)(2)D(3) in inhibiting cancer cell growth and invasion because of its weaker binding to vitamin D binding protein (DBP), and more resistance to CYP24A1-dependent metabolism. In this study, we examined the metabolism of MART-10 and two other 2α-substituted analogs, 2α-(3-hydroxypropoxy)-1α,25(OH)(2)D(3) (O2C3) and 2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (O1C3) by using human liver microsomes and human P450s. We demonstrated that O2C3 was converted to 1α,2α,25(OH)(3)D(3) in human liver microsomes, whereas both O1C3 and MART-10 were hardly metabolized. The metabolism of O2C3 was significantly inhibited by ketoconazole, and the recombinant human CYP3A4 converted O2C3 to 1α,2α,25(OH)(3)D(3), which suggests that CYP3A4 is responsible for the metabolism of O2C3 in human liver. The k(cat)/K(m) values of CYP3A4 for O1C3 and MART-10 are much smaller than that for O2C3. The k(cat)/K(m) values of human CYP24A1 for the three analogs are 1% (MART-10), 3% (O2C3), and 4% (O1C3) of that for 1α,25(OH)(2)D(3), indicating that MART-10 is the most resistant to CYP24A1 hydroxylation. On the other hand, 1α,2α,25(OH)(3)D(3), the metabolite of O2C3 by CYP3A4, was metabolized by CYP24A1 via multiple pathways similar to 1α,25(OH)(2)D(3), which suggests that O2C3 can be metabolized by two sequential hydroxylations, first by CYP3A4 and then by CYP24A1 in human body. These results suggest that modification at C-2α position and C-19 demethylenation markedly change metabolic profiles and biological activities of vitamin D analogs.

Hyperbaric oxygen (HBO₂) therapy has a long history of use. However, its effect on thrombus formation is unclear. Many reports have indicated that it accelerates platelet aggregation, which suggests that it may increase thrombotic events. However, clinical trial results are inconsistent, and no previous reports have demonstrated that HBO₂therapy does in fact increase thrombotic events. Here, we used a total thrombus formation analysis system (T-TAS) to analyze changes in thrombus formation in a specimen group exposed to constant hyperbaric pressure in vitro, and a control group.Blood samples were collected from two sets of 10 healthy volunteers (mean age, 28.8 years) with no underlying disease. In the pressurized group, a constant pressure was applied to specimens in temperature-controlled test tubes; the non-pressurized group served as the control. Thrombus formation in samples from both the pressurized and control groups were measured using the T-TAS immediately, 20 minutes, and 40 minutes after pressurization.In the pressurized group, the onset of thrombus formation was significantly delayed, confirming a reduction in thrombus formation ability. However, the reduced ability for thrombus formation in the pressurized group recovered to the level of the control group. That is, the change in thrombus formation ability caused by pressure was proven to be reversible.We are the first to ascertain a decrease in the thrombus formation ability in specimens exposed to hyperbaric pressure using a T-TAS, which is capable of measuring thrombus formation in an environment similar to that in vivo.

Table of contentsP1 D-Dimer in adult patients with presumed sepsis and their clinical outcomesSurinder Kumar Sharma, Anurag Rohatgi, Mansi BajajP2 Diagnosis of infection utilizing Acellix CD64Charles L. Sprung, Ricardo Calderon Morales, Harvey Kasdan, Allon Reiter, Tobias Volker, Julien MeissonnierP3 High levels of phenylcarboxylic acids reflect the severity in ICU patients and affect phagocytic activity of neutrophilsNatalia Beloborodova, Viktor Moroz, Aleksandra Bedova, Yulia Sarshor, Artem Osipov, Katerina ChernevskayaP4 The role of bacterial phenolic metabolites in mitochondrial dysfunctionNadezhda Fedotcheva, Ekaterina Chernevskaya, Natalia BeloborodovaP5 The early diagnosis of severe sepsis and judgment of rapid transport to critical care center: better prognostic factorHisashi Imahase, Kosuke C Yamada, Yuichiro Sakamoto, Miho Ohta, Ryota Sakurai, Mayuko Yahata, Mitsuru Umeka, Toru Miike, Hiroyuki Koami, Futoshi Nagashima, Takashi Iwamura, Satoshi InoueP6 Translational neuromodulation of the immune systemZhifeng Li, Dennis Grech, Patrick Morcillo, Alex Bekker, Luis UlloaP7 Pathway-level meta-analysis reveals transcriptional signature of septic shockSamanwoy Mukhopadhyay, Abhay D Pandey, Samsiddhi Bhattacharjee, Saroj K MohapatraP8 Antibiotic dosing in septic patients on the critical care unit - a literature reviewJulie K WilsonP9 Pandemic of Escherichia coli clone O25: H4-ST131 producing CTX-M-15 extended spectrum- β- lactamase- as serious cause of multidrug resistance extraintestinal pathogenic E. coli infections in IndiaSavita Jadhav, Rabindra Nath Misra, Nageswari Gandham, Kalpana Angadi, Chanda Vywahare, Neetu Gupta, Deepali DesaiP10 Detection and characterization of meningitis using a DDA-based mass spectrometry approachAnahita Bakochi, Tirthankar Mohanty, Adam Linder, Johan MalmströmP11 Diagnostic usefulness of lipid profile and procalcitonin in sepsis and trauma patientsDimple Anand, Seema Bhargava, Lalit Mohan Srivastava, Sumit RayP12 Heparin – a novel therapeutic in sepsis?Jane Fisher, Peter Bentzer, Adam LinderP13 Hypothalamic impairment is associated with vasopressin deficiency during sepsisLuis Henrique Angenendt da Costa, Nilton Nascimentos dos Santos Júnior Carlos Henrique Rocha Catalão, Maria José Alves da RochaP14 Presepsin (soluble CD14 subtype) is a dependable prognostic marker in critical septic patientsAlfredo Focà, Cinzia Peronace, Giovanni Matera, Aida Giancotti, Giorgio Settimo Barreca, Angela Quirino, Maria Teresa Loria, Pio Settembre, Maria Carla Liberto, Bruno AmanteaP15 Safety and efficacy of gelatin-containing solutions versus crystalloids and albumin - a systematic review with quantitative and qualitative summariesChristiane Hartog, Christiane Hartog, Claudia Moeller, Carolin Fleischmann, Daniel Thomas-Rueddel, Vlasislav Vlasakov, Bram Rochwerg, Philip Theurer, Konrad ReinhartP16 Immunomodulatory properties of peripheral blood mesenchymal stem cells following endotoxin stimulation in an equine modelAnna E. Smith, Sandra D. TaylorP17 Frequency and outcome of early sepsis-associated coagulopathyChristopher Da Costa, Amanda Radford, Terry Lee, Joel Singer, John Boyd, David Fineberg, Mark Williams, James A Russell

Oral candidiasis is closely associated with changes in oral fungal biodiversity and is caused primarily by Candida albicans. However, the widespread use of empiric and prophylactic antifungal drugs has caused a shift in fungal biodiversity towards other Candida or yeast species. Recently, next-generation sequencing (NGS) has provided an improvement over conventional culture techniques, allowing rapid comprehensive analysis of oral fungal biodiversity. In this study, we used NGS to examine the oral fungal biodiversity of 27 patients with pseudomembranous oral candidiasis (POC) and 66 healthy controls. The total number of fungal species in patients with POC and healthy controls was 67 and 86, respectively. The copy number of total PCR products and the proportion of non-C. albicans, especially C. dubliniensis, in patients with POC, were higher than those in healthy controls. The detection patterns in patients with POC were similar to those in controls after antifungal treatment. Interestingly, the number of fungal species and the copy number of total PCR products in healthy controls increased with aging. These results suggest that high fungal biodiversity and aging might be involved in the pathogenesis of oral candidiasis. We therefore conclude that NGS is a useful technique for investigating oral candida infections.

Sesamin and episesamin are two epimeric lignans that are found in refined sesame oil. Commercially available sesamin supplements contain both sesamin and episesamin at an approximate 1:1 ratio. Our previous study clarified the sequential metabolism of sesamin by cytochrome P450 (P450) and UDP-glucuronosyltransferase in human liver. In addition, we revealed that sesamin caused a mechanism-based inhibition (MBI) of CYP2C9, the P450 enzyme responsible for sesamin monocatecholization. In the present study, we compared the metabolism and the MBI of episesamin with those of sesamin. Episesamin was first metabolized to the two epimers of monocatechol, S- and R-monocatechols in human liver microsomes. The P450 enzymes responsible for S- and R-monocatechol formation were CYP2C9 and CYP1A2, respectively. The contribution of CYP2C9 was much larger than that of CYP1A2 in sesamin metabolism, whereas the contribution of CYP2C9 was almost equal to that of CYP1A2 in episesamin metabolism. Docking of episesamin to the active site of CYP1A2 explained the stereoselectivity in CYP1A2-dependent episesamin monocatecholization. Similar to sesamin, the episesamin S- and R-monocatechols were further metabolized to dicatechol, glucuronide, and methylate metabolites in human liver; however, the contribution of each reaction was significantly different between sesamin and episesamin. The liver microsomes from CYP2C19 ultra-rapid metabolizers showed a significant amount of episesamin dicatechol. In this study, we have revealed significantly different metabolism by P450, UDP-glucuronosyltransferase, and catechol-O-methyltransferase for sesamin and episesamin, resulting in different biological effects.

According to the prevailing paradigm, 1α-hydroxylation of 25-hydroxyvitamin D3 (25(OH)D3) and its analogs is a pre-requisite step for their biological effects. We previously reported that 25-hydroxy-19-nor-vitamin D3 (25(OH)-19-nor-D3) had anti-proliferative activity in a cell line, PZ-HPV-7, which was derived from human non-cancerous prostate tissue, and suggested that 25(OH)-19-nor-D3 acted after 1α-hydroxylation by vitamin D 1α-hydroxylase (CYP27B1). However, metabolic studies of 25(OH)-19-nor-D3 using recombinant CYP27B1 revealed that 25(OH)-19-nor-D3 was rarely subjected to 1α-hydroxylation. Therefore, in this report, we attempted to clarify the mechanism of 25(OH)-19-nor-D3 action in intact cells using PZ-HPV-7 prostate cells. After incubating the cells with 25(OH)-19-nor-D3, eight metabolites of 24-hydroxylase (CYP24A1) were detected, whereas no products of CYP27B1 including 1α,25-dihydroxy-19-nor-vitamin D3 (1α,25(OH)2-19-nor-D3) were found. Furthermore, the time-dependent nuclear translocation of vitamin D receptor (VDR) and the subsequent transactivation of cyp24A1 gene in the presence of 25(OH)-19-nor-D3 were almost identical as those induced by 1α,25(OH)2-19-nor-D3. These results strongly suggest that 25(OH)-19-nor-D3 directly binds to VDR as a ligand and transports VDR into the nucleus to induce transcription of cyp24A1 gene. In addition, knock down of cyp27B1 gene did not affect the anti-proliferative activity of 25(OH)-19-nor-D3, whereas knock down of VDR attenuated the inhibitory effect. Thus, our results clearly demonstrate that the anti-proliferative activity of 25(OH)-19-nor-D3 is VDR dependent but 1α-hydroxylation independent, suggesting that 25(OH)D3 analogs such as 25(OH)-19-nor-D3 could be attractive candidates for anticancer therapy.

Metabolism of sesamin by cytochrome P450 (P450) was examined using yeast expression system and human liver microsomes. Saccharomyces cerevisiae cells expressing each of human P450 isoforms (CYP1A1, 1A2, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, and 3A4) were cultivated with sesamin, and monocatechol metabolite was observed in most of P450s. Kinetic analysis using the microsomal fractions of the recombinant S. cerevisiae cells revealed that CYP2C19 had the largest k(cat)/K(m) value. Based on the kinetic data and average contents of the P450 isoforms in the human liver, the putative contribution of P450s for sesamin metabolism was large in the order of CYP2C9, 1A2, 2C19, and 2D6. A good correlation was observed between sesamin catecholization activity and CYP2C9-specific activity in in vitro studies using 10 individual human liver microsomes, strongly suggesting that CYP2C9 is the most important P450 isoform for sesamin catecholization in human liver. Inhibition studies using each anti-P450 isoform-specific antibody confirmed that CYP2C9 was the most important, and the secondary most important P450 was CYP1A2. We also examined the inhibitory effect of sesamin for P450 isoform-specific activities and found a mechanism-based inhibition of CYP2C9 by sesamin. In contrast, no mechanism-based inhibition by sesamin was observed in CYP1A2-specific activity. Our findings strongly suggest that further studies are needed to reveal the interaction between sesamin and therapeutic drugs mainly metabolized by CYP2C9.

Our previous studies revealed that the double variant of cytochrome P450 (CYP)105A1, R73V/R84A, has a high ability to convert vitamin D(3) to its biologically active form, 1α,25-dihydroxyvitamin D(3) [1α,25(OH)(2)D(3)], suggesting the possibility for R73V/R84A to produce 1α,25(OH)(2)D(3). Because Actinomycetes, including Streptomyces, exhibit properties that have potential advantages in the synthesis of secondary metabolites of industrial and medical importance, we examined the expression of R73V/R84A in Streptomyces lividans TK23 cells under the control of the tipA promoter. As expected, the metabolites 25-hydroxyvitamin D(3) [25(OH)D(3)] and 1α,25(OH)(2)D(3) were detected in the cell culture of the recombinant S. lividans. A large amount of 1α,25(OH)(2)D(3), the second-step metabolite of vitamin D(3), was observed, although a considerable amount of vitamin D(3) still remained in the culture. In addition, novel polar metabolites 1α,25(R),26(OH)(3)D(3) and 1α,25(S),26(OH)(3)D(3), both of which are known to have high antiproliferative activity and low calcemic activity, were observed at a ratio of 5:1. The crystal structure of the double variant with 1α,25(OH)(2)D(3) and a docking model of 1α,25(OH)(2)D(3) in its active site strongly suggest a hydrogen-bond network including the 1α-hydroxyl group, and several water molecules play an important role in the substrate-binding for 26-hydroxylation. In conclusion, we have demonstrated that R73V/R84A can catalyze hydroxylations at C25, C1 and C26 (C27) positions of vitamin D(3) to produce biologically useful compounds.

We cloned full-length cDNAs of 130 cytochrome P450s (P450s) derived from Phanerochaete chrysosporium and successfully expressed 70 isoforms in Saccharomyces cerevisiae. To elucidate substrate specificity of P. chrysosporium P450s, we examined various substrates including steroid hormones, several drugs, flavonoids and polycyclic aromatic hydrocarbons using the recombinant S. cerevisiae cells. Of these P450s, two CYPs designated as PcCYP50c and PcCYP142c with 14% identity in their amino acid sequences catalyse 3'-hydroxylation of flavone and O-deethylation of 7-ethoxycoumarin. Kinetic data of both enzymes on both reactions fitted not to the Michaelis-Menten equation but to Hill's equation with a coefficient of 2, suggesting that two substrates bind to the active site. Molecular modelling of PcCYP50c and a docking study of flavone to its active site supported this hypothesis. The enzymatic properties of PcCYP50c and PcCYP142c resemble mammalian drug-metabolizing P450s, suggesting that their physiological roles are metabolism of xenobiotics. It is noted that these unique P. chrysosporium P450s have a potential for the production of useful flavonoids.

Our previous study demonstrated that 25-hydroxy-19-nor-vitamin D(3) [25(OH)-19-nor-D(3)] inhibited the proliferation of immortalized noncancerous PZ-HPV-7 prostate cells similar to 1 alpha,25-dihydroxyvitamin D(3) [1 alpha,25(OH)(2)D(3)], suggesting that 25(OH)-19-nor-D(3) might be converted to 1 alpha,25-dihydroxy-19-nor-vitamin D(3) [1 alpha,25(OH)(2)-19-nor-D(3)] by CYP27B1 before exerting its antiproliferative activity. Using an in vitro cell-free model to study the kinetics of CYP27B1-dependent 1 alpha-hydroxylation of 25(OH)-19-nor-D(3) and 25-hydroxyvitamin D(3) [25(OH)D(3)] and CYP24A1-dependent hydroxylation of 1 alpha,25(OH)-19-nor-D(3) and 1 alpha,25(OH)(2)D(3), we found that k(cat)/K(m) for 1 alpha-hydroxylation of 25(OH)-19-nor-D(3) was less than 0.1% of that for 25(OH)D(3), and the k(cat)/K(m) value for 24-hydroxylation was not significantly different between 1 alpha,25(OH)(2)-19-nor-D(3) and 1 alpha,25(OH)(2)D(3). The data suggest a much slower formation and a similar rate of degradation of 1 alpha,25(OH)(2)-19-nor-D(3) compared with 1 alpha,25(OH)(2)D(3). We then analyzed the metabolites of 25(OH)D(3) and 25(OH)-19-nor-D(3) in PZ-HPV-7 cells by high-performance liquid chromatography. We found that a peak that comigrated with 1 alpha,25(OH)(2)D(3) was detected in cells incubated with 25(OH)D(3), whereas no 1 alpha,25(OH)(2)-19-nor-D(3) was detected in cells incubated with 25(OH)-19-nor-D(3). Thus, the present results do not support our previous hypothesis that 25(OH)-19-nor-D(3) is converted to 1 alpha,25(OH)(2)-19-nor-D(3) by CYP27B1 in prostate cells to inhibit cell proliferation. We hypothesize that 25(OH)-19-nor-D(3) by itself may have a novel mechanism to activate vitamin D receptor or it is metabolized in prostate cells to an unknown metabolite with antiproliferative activity without 1 alpha-hydroxylation. Thus, the results suggest that 25(OH)-19-nor-D(3) has potential as an attractive agent for prostate cancer therapy.

CYP27A1 catalyzes vitamin D(3) 25-hydroxylation and further hydroxylation at C-1alpha, C-24 or C-26(27). Molecular modeling of human CYP27A1 and docking with 25-hydroxyvitamin D(3) predicted that Gln 85 might be important for 1alpha-hydroxylation activity of CYP27A1 by forming a hydrogen bond with the 25-OH group of 25-hydroxyvitamin D(3). Expectedly, the mutant Q85H expressed in Escherichia coli showed no detectable 1alpha-hydroxylation activity toward 25-hydroxyvitamin D(3). In addition, Q85H prefers 24-hydroxylation toward 25-hydroxyvitamin D(3) whereas the wild-type prefers 26(27)-hydroxylation. A molecular modeling study also suggests that Gln 85 of CYP27A1 simultaneously interacts with Asn 107 and the hydroxyl group of the substrate. The fact that Q85L did not contain a heme molecule suggests that the hydrogen bond between Gln 85 and Asn 107 is important for protein folding of CYP27A1. Based on these results, it is possible that Gln 85 plays essential roles in both substrate-binding and protein folding.

Background IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS), so-called Mikulicz’s disease, is characterized by elevated serum IgG4 and infiltration of IgG4-positive plasma cells in glandular tissues. Recently, several studies reported both malignant lymphoma developed on the background of IgG4-associated conditions and IgG4-producing malignant lymphoma (non-IgG4-related disease). Case presentation We report on the case of a 70-year-old man who was strongly suspected IgG4-DS because of high serum IgG4 concentration (215 mg/dl) and bilateral swelling of parotid and submandibular glands. Biopsies of cervical lymph node and a portion of submandibular gland were performed. These histopathological findings subsequently confirmed a diagnosis of marginal zone B cell lymphoma. Conclusion Differential diagnosis of IgG4-DS is necessary from other disorders, including Sjögren’s syndrome, sarcoidosis, Castleman’s disease, Wegener’s granulomatosis, lymphoma, and cancer. We suggest that biopsy of swollen lesions is important for a definitive diagnosis of IgG4-DS and discuss the mechanism of development in this case.

The metabolism of eldecalcitol (ED-71), a 2β-hydroxypropoxylated analog of the active form of vitamin D3 was investigated by using in vitro systems. ED-71 was metabolized to 1α,2β,25-trihydroxyvitamin D3 (1α,2β,25(OH)3D3) in human small intestine and liver microsomes. To identify the enzymes involved in this metabolism, we examined NADPH-dependent metabolism by recombinant P450 isoforms belonging to the CYP1, 2, and 3 families, and revealed that CYP3A4 had the activity. However, the CYP3A4 -specific inhibitor, ketoconazole, decreased the activity in human liver microsomes by only 36%, suggesting that other enzymes could be involved in ED-71 metabolism. Because metabolism was dramatically inhibited by cyanide, we assumed that sterol C4-methyl oxidase like gene product (SC4MOL) might contribute to the metabolism of ED-71. It is noted that SC4MOL is physiologically essential for cholesterol synthesis. Recombinant human SC4MOL expressed in COS7, Saccharomyces cerevisiae, or Escherichia coli cells converted ED-71 to 1α,2β,25(OH)3D3. Furthermore, we evaluated the metabolism of ED-71 by recombinant CYP24A1, which plays an important role in the metabolism of the active form of vitamin D3 (1α,25(OH)2D3) and its analogs. The k cat/K m value for 24- or 23-hydroxylation of ED-71 was only 3% of that for 1α,25(OH)2D3, indicating that ED-71 was resistant to CYP24A1-dependent catabolism. Among the three enzymes catalyzing ED-71, SC4MOL appears to be most important in the metabolism of ED-71. To the best of our knowledge, this is the first study showing that SC4MOL can function as a drug-metabolizing enzyme. The yeast and E. coli expression systems for SC4MOL could be useful for structure-function analyses of SC4MOL.

Salt-inducible kinases (SIKs), members of the 5′-AMP-activated protein kinase (AMPK) family, are proposed to be important suppressors of gluconeogenic programs in the liver via the phosphorylation-dependent inactivation of the CREB-specific coactivator CRTC2. Although a dramatic phenotype for glucose metabolism has been found in SIK3-KO mice, additional complex phenotypes, dysregulation of bile acids, cholesterol, and fat homeostasis can render it difficult to discuss the hepatic functions of SIK3. The aim of this study was to examine the cell autonomous actions of SIK3 in hepatocytes. To eliminate systemic effects, we prepared primary hepatocytes and screened the small compounds suppressing SIK3 signaling cascades. SIK3-KO primary hepatocytes produced glucose more quickly after treatment with the cAMP agonist forskolin than the WT hepatocytes, which was accompanied by enhanced gluconeogenic gene expression and CRTC2 dephosphorylation. Reporter-based screening identified pterosin B as a SIK3 signaling-specific inhibitor. Pterosin B suppressed SIK3 downstream cascades by up-regulating the phosphorylation levels in the SIK3 C-terminal regulatory domain. When pterosin B promoted glucose production by up-regulating gluconeogenic gene expression in mouse hepatoma AML-12 cells, it decreased the glycogen content and stimulated an association between the glycogen phosphorylase kinase gamma subunit (PHKG2) and SIK3. PHKG2 phosphorylated the peptides with sequences of the C-terminal domain of SIK3. Here we found that the levels of active AMPK were higher both in the SIK3-KO hepatocytes and in pterosin B-treated AML-12 cells than in their controls. These results suggest that SIK3, rather than SIK1, SIK2, or AMPKs, acts as the predominant suppressor in gluconeogenic gene expression in the hepatocytes.

Recently, we demonstrated that some A-ring-modified vitamin D3 analogs had unique biological activity. Of these analogs, 2alpha-propoxy-1alpha,25(OH)2D3 (C3O1) and 2alpha-(3-hydroxypropoxy)-1alpha,25(OH)2D3 (O2C3) were examined for metabolism by CYP27A1 and CYP24A1. Surprisingly, CYP27A1 catalyzed the conversion from C3O1 to O2C3, which has 3 times more affinity for vitamin D receptor than C3O1. Thus, the conversion from C3O1 to O2C3 by CYP27A1 is considered to be a metabolic activation process. Five metabolites were detected in the metabolism of C3O1 and O2C3 by human CYP24A1 including both C-23 and C-24 oxidation pathways. On the other hand, three metabolites of the C-24 oxidation pathway were detected in their metabolism by rat CYP24A1, indicating a species-based difference in the CYP24A1-dependent metabolism of C3O1 and O2C3 between humans and rats. Kinetic analysis revealed that the Km and kcat values of human CYP24A1 for O2C3 are, respectively, approximately 16 times more and 3 times less than those for 1alpha,25(OH)2D3. Thus, the catalytic efficiency, kcat/Km, of human CYP24A1 for O2C3 is only 2% of 1alpha,25(OH)2D3. These results and a high calcium effect of C3O1 and O2C3 in animal experiments using rats suggest that C3O1 and O2C3 are promising for clinical treatment of osteoporosis.

The expression of mouse CYP27B1 in Escherichia coli has been dramatically enhanced by coexpression of GroEL/ES. To reveal the enzymatic properties of CYP27B1, we measured its hydroxylation activity toward vitamin D3 and 1alpha-hydroxyvitamin D3 (1alpha(OH)D3) in addition to the physiological substrate 25(OH)D3. Surprisingly, CYP27B1 converted vitamin D3 to 1alpha,25(OH)D3. Both 1alpha-hydroxylation activity toward vitamin D3, and 25-hydroxylation activity toward 1alpha(OH)D3 were observed. The Km and Vmax values for 25-hydroxylation activity toward 1alpha(OH)D3 were estimated to be 1.7 microM and 0.51 mol/min/mol P450, respectively, while those for 1alpha-hydroxylation activity toward 25(OH)D3 were 0.050 microM and 2.73 mol/min/mol P450, respectively. Note that the substrate must be fixed in the opposite direction in the substrate-binding pocket of CYP27B1 between 1alpha-hydroxylation and 25-hydroxylation. Based on these results and the fact that human CYP27A1 and Streptomyces CYP105A1 also convert vitamin D3 to 1alpha,25(OH)D3, 1alpha-hydroxylation, and 25-hydroxylation of vitamin D3 appear to be closely linked together.