Quantitative prediction of CYP3A induction-mediated drug-drug interactions in clinical practice.

There have been no reports on the quantitative prediction of CYP3A induction-mediated decreases in AUC and Cmax for drug candidates identified as a "victims" of CYP3A induction. Our previous study separately evaluated the fold-induction of hepatic and intestinal CYP3A by known inducers using clinical induction data and revealed that we were able to quantitatively predict the AUC ratio (AUCR) of a few CYP3A substrates in the presence and absence of CYP3A inducers. In the present study, we investigate the predictability of AUCR and also Cmax ratio (CmaxR) in additional 54 clinical studies. The fraction metabolized by CYP3A (fm), the intestinal bioavailability (Fg), and the hepatic intrinsic clearance (CLint) of substrates were determined by the in vitro experiments as well as clinical data used for calculating AUCR and CmaxR. The result showed that 65-69% and 65-67% of predictions were within 2-fold of observed AUCR and CmaxR, respectively. A simulation using multiple parameter combinations suggested that the variability of fm and Fg within a certain range might have a minimal impact on the calculation output. These findings suggest that clinical AUCR and CmaxR of CYP3A substrates can be quantitatively predicted from the preclinical stage.

[On the formation of Russian pulmonology: the development of the doctrine of lung diseases (first half of the 20th century)].

The articles on the history of Russian pulmonology presented in the historical, medical and therapeutic literature contain materials for this history, but their authors did not solve the problem of its consistent presentation, highlighting the stages of formation and founders. The authors of this study critically reviewed the literary and archival primary sources, for the first time proposed the identification of three stages in the development of Russian pulmonology and indicated eight of its founders at these stages. The abundance of material did not allow us to present it in one article. This article is devoted to the 1st stage of the history of pulmonology - the formation of the doctrine of lung diseases. The second (development of pulmonology as an independent scientific direction in internal diseases) and the third (organizational design of pulmonology as a new independent clinical scientific and educational discipline and medical specialty, i.e. its institutionalization) stages will be discussed in the next articles.

Monitoring Cell Cytoskeleton Variations upon Piezoelectric Stimulation: Implications for the Immune System.

Piezoelectric stimulation can have a significant impact on different cellular functions with possible applications in several fields, such as regenerative medicine, cancer therapy, and immunoregulation. For example, piezoelectric stimulation has been shown to modulate cytoskeleton variations: the implications of this effect range from the regulation of migration and invasion of cancer cells to the activation of pro- or anti-inflammatory phenotypes in immune cells. In this chapter, we will present different methodologies to evaluate cytoskeleton variations, focusing on modifications on f-/g-actin ratio and on the migration and invasion ability of tumor cells.

A case report of Fournier's gangrene: Imaging ultrasound and computed tomography (CT) scan.

Necrotizing fasciitis and/or Fournier's Gangrene is a rare, life-threatening soft tissue infection that, if not treated promptly, can immediately develop into systemic toxicity. It affects the genital, perineal, and perineal tissues, predominantly affecting men but can be seen in women. The diagnosis is often made clinically but radiologic examinations are helpful to determine the extent of the infection and can aid preoperative planning. Treatment consists of immediate and aggressive surgical debridement of necrotized tissue, broad-spectrum antibiotics, and early resuscitation. Here, we present a 56-year-old male patient with Fournier's gangrene and describe the physical examination, bedside sonographic, and computed tomography findings. These findings can aid in the evaluation of patients with worrying symptoms so that antibiotics can be administered immediately and specialists can be consulted as needed.

A reduction in the vascular smooth muscle cell focal adhesion component syndecan-4 is associated with abdominal aortic aneurysm formation.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a serious vascular disease for which there is no effective drug treatment. The incidence of AAA increases significantly as a subject ages, and the molecular mechanism of AAA formation remains elusive. In the present study, we investigated the role of syndecan-4 (SDC4), an important component of focal adhesions, in AAA formation and its association with phenotypic changes in vascular smooth muscle cells (VSMCs). METHODS AND RESULTS: The protein expression levels of SDC4 were significantly decreased in human AAA tissue and those of an AAA mouse model. Moreover, SDC4 knockout (KO) in mice accelerated the formation and rupture of AAAs induced by angiotensin II (Ang II) and calcium chloride (CaCl2 ) Mechanistically, the decrease in SDC4 led to the transformation of cultured VSMCs from a contractile to a secretory phenotype. The RhoA-F/G-actin-myocardin-related transcription factor-A (MRTF-A) signalling pathway was shown to be involved in SDC4-dependent VSMC alteration. Sphingosine-1-phosphate (S1P), a G-protein-coupled receptor, attenuated the AAA formation in SDC4-KO and wild-type (WT) mice in response to Ang II and CaCl2 stimulation. CONCLUSION: We herein demonstrated that silencing SDC4 was associated with increased AAA formation and phenotypic changes in VSMCs via the RhoA-F/G-actin-MRTF-A pathway. These findings indicated that a reduction in SDC4 expression was an important pathological alteration and potential therapeutic target for AAA formation.

Chimeric Fusion (F) and Attachment (G) Glycoprotein Antigen Delivery by mRNA as a Candidate Nipah Vaccine.

Nipah virus (NiV) represents a significant pandemic threat with zoonotic transmission from bats-to-humans with almost annual regional outbreaks characterized by documented human-to-human transmission and high fatality rates. Currently, no vaccine against NiV has been approved. Structure-based design and protein engineering principles were applied to stabilize the fusion (F) protein in its prefusion trimeric conformation (pre-F) to improve expression and increase immunogenicity. We covalently linked the stabilized pre-F through trimerization domains at the C-terminus to three attachment protein (G) monomers, forming a chimeric design. These studies detailed here focus on mRNA delivery of NiV immunogens in mice, assessment of mRNA immunogen-specific design elements and their effects on humoral and cellular immunogenicity. The pre-F/G chimera elicited a strong neutralizing antibody response and a superior NiV-specific Tfh and other effector T cell response compared to G alone across both the mRNA and protein platforms. These findings enabled final candidate selection of pre-F/G Fd for clinical development.

Ectopic expression of 35 kDa and knocking down of 78 kDa SG2NAs induce cytoskeletal reorganization, alter membrane sialylation, and modulate the markers of EMT.

SG2NA is a protein of the striatin family that organizes STRIPAK complexes. It has splice variants expressing differentially in tissues. Its 78 kDa isoform regulates cell cycle, maintains homeostasis in the endoplasmic reticulum, and prevents oxidative injuries. The 35 kDa variant is devoid of the signature WD-40 repeats in the carboxy terminal, and its function is unknown. We expressed it in NIH 3T3 cells that otherwise express 78 kDa variant only. These cells (35 EE) have altered morphology, faster rate of migration, and enhanced growth as measured by the MTT assay. Similar phenotypes were also seen in cells where the endogenous 78 kDa isoform was downregulated by siRNA (78 KD). Proteomic analyses showed that several cancer-associated proteins are modulated in both 35 EE and 78 KD cells. The 35 EE cells have diffused actin fibers, distinctive ultrastructure, reduced sialylation, and increased expression of MMP2 & 9. The 78 KD cells also had diffused actin fibers and an upregulated expression of MMP2. In both cells, markers epithelial to mesenchymal transition (EMT) viz, E- & N-cadherins, ß-catenin, slug, vimentin, and ZO-1 were modulated partially in tune with the EMT process. Since NIH 3T3 cells are mesenchymal, we also expressed 35 kDa SG2NA in MCF-7 cells of epithelial origin. In these cells (MCF-7-35), the actin fibers were also diffused and the modulation of the markers was more in tune with the EMT process. However, unlike in 35 EE cells, in MCF-7-35 cells, membrane sialylation rather increased. We infer that ectopic expression of 35 kDa and downregulation of 78 kDa SG2NAs partially induce transformed phenotypes.

Structure-Based Design of Nipah Virus Vaccines: A Generalizable Approach to Paramyxovirus Immunogen Development.

Licensed vaccines or therapeutics are rarely available for pathogens with epidemic or pandemic potential. Developing interventions for specific pathogens and defining generalizable approaches for related pathogens is a global priority and inherent to the UN Sustainable Development Goals. Nipah virus (NiV) poses a significant epidemic threat, and zoonotic transmission from bats-to-humans with high fatality rates occurs almost annually. Human-to-human transmission of NiV has been documented in recent outbreaks leading public health officials and government agencies to declare an urgent need for effective vaccines and therapeutics. Here, we evaluate NiV vaccine antigen design options including the fusion glycoprotein (F) and the major attachment glycoprotein (G). A stabilized prefusion F (pre-F), multimeric G constructs, and chimeric proteins containing both pre-F and G were developed as protein subunit candidate vaccines. The proteins were evaluated for antigenicity and structural integrity using kinetic binding assays, electron microscopy, and other biophysical properties. Immunogenicity of the vaccine antigens was evaluated in mice. The stabilized pre-F trimer and hexameric G immunogens both induced serum neutralizing activity in mice, while the post-F trimer immunogen did not elicit neutralizing activity. The pre-F trimer covalently linked to three G monomers (pre-F/G) induced potent neutralizing antibody activity, elicited responses to the greatest diversity of antigenic sites, and is the lead candidate for clinical development. The specific stabilizing mutations and immunogen designs utilized for NiV were successfully applied to other henipaviruses, supporting the concept of identifying generalizable solutions for prototype pathogens as an approach to pandemic preparedness.

Neoclerodane diterpenoids from Scutellaria barbata with cytotoxic activities.

Two new neoclerodane diterpenoids, barbatin F (1), barbatin G (2) together with four known compounds, scutebata A (3), scutebata B (4), scutebata C (5) and scutebata P (6) were isolated from the whole plant of Scutellaria barbata D.Don. Their structures were elucidated on the basis of spectroscopic studies. In vitro cytotoxicity of selected compounds against cancer cell lines LoVo, SMMC-7721, HCT-116, and MCF-7 were evaluated, compound 1 and 2 showed weak cytotoxic activities against HCT-116 colon cancer cell lines with IC50 value of 44.3, 32.3 µM, respectively, while compound 3 and 4 exhibited moderate cytotoxic activities against four tested human cancer cell lines with IC50 values of 5.31～28.5 µM.

Polycystic Ovarian Syndrome: Correlation between clinical hyperandrogenism, anthropometric, metabolic and endocrine parameters.

OBJECTIVE: To evaluate the correlation between clinical hyperandrogenism-hirsutism assessed by modified Ferriman-Gallwey (F-G) score, anthropometric, metabolic and endocrine parameters among PCOS infertile women. METHODS: This observational study after approval of FRC & ERC of BUMDC was conducted from September 2018-March 2019. It included seventy women aged 20-40 years who presented in infertility clinic of a local Hospital in Karachi. After written informed consent participants were enrolled as per the inclusion criteria of the study and evaluated for cyclical pattern (oligomenorrhoea, amenorrhoea, polymenorrhea), physical (weight, height, BMI), anthropometric, (waist circumference, hip circumference, waist to hip ratio, hirsutism), metabolic (carbohydrate, lipid & protein) and endocrine parameters (serum FSH, LH, LH/FSH ratio, serum testosterone, prolactin and progesterone level). Hirsutism was assessed by visual method through modified F-G score and Pearson correlation was determined between hirsutism and other study parameters. RESULTS: A positive Pearson correlation is found between hirsutism and body weight, BMI, waist and hip circumference, waist to hip ratio (WHR), very low density lipoprotein, cholesterol, triglycerides and testosterone levels. CONCLUSION: Hirsutism has correlation with anthropometric, metabolic and hyperandrgenic disorders in PCOS infertile women as assessed by modified F-G score.

Prevalence of antibodies to ganglioside and Hep 2 in Gaucher, Niemann - Pick type C and Sanfilippo diseases.

Lysosomal Storage Diseases (LSDs) are rare genetic diseases, the majority of which are caused by specific lysosomal enzyme deficiencies and all are characterized by malfunctioning lysosomes. Lysosomes are key regulators of many different cellular processes and are vital for the function of the immune system. Several studies have shown the coexistence of LSDs and immune abnormalities. In this study, we investigated the presence of autoantibodies in the plasma of patients with Gaucher disease (GD; n = 6), Sanfilippo Syndrome B (SFB; n = 8) and Niemann - Pick type C disease (NPC; n = 5) before and following Miglustat treatment (n = 3). All were examined for antibodies to antigens of Hep-2 cells and antiganglioside antibodies (AGSA). No autoantibodies were detected in GD patients. 3/8 SFB patients showed only AGSA (2/3 IgM / IgG; 1/3 IgG), 3/8 only anti-Sm E/F and 2/8 showed both IgM / IgG or IgG AGSA and anti-Sm E/F. 3/5 NPC patients showed AGSA (2/3 IgM and IgG, 1/3 IgM) and one anti-Sm E/F and IgM AGSA. Following treatment one patient with no AGSA developed IgM AGSA and two with both IgG and IgM showed only IgG AGSA. In our study, investigating similar numbers of patients, autoantibodies were observed in NPC and SFB patients but not in GD patients. Our findings suggest that, independently of the development of an autoimmune disease in patients with LSDs, there seems to be an autoimmune activation that differs in different disorders. Further studies including more patients, also at different stages of disease and treatment, are needed in order to get further insight into the immune irregularities associated with different LSDs and their significance.

Dietary supplemental vitamin D3 enhances phosphorus absorption and utilisation by regulating gene expression of related phosphate transporters in the small intestine of broilers.

The present study was carried out to evaluate the effect of dietary supplemental vitamin D3 (VD3) on P absorption and utilisation as well as its related mechanisms in the small intestine of broilers. A total of 384 1-d-old Arbor Acres male broilers were assigned randomly into four treatments following a completely randomised design with a 2 (dietary non-phytate P (NPP) contents: 0·43 and 0·22 %)×2 (dietary VD3 supplemental levels: 0 and 87·5 µg/kg) factorial arrangement. The experiment lasted for 22 d. The results showed that P contents in serum from the hepatic portal vein and tibia ash of broilers were higher (P<0·05) for 0·43 % NPP than for 0·22 % NPP. The type IIb Na-dependent phosphate cotransporter (NaP-IIb) protein expressions in the duodenum and ileum were higher (P<0·05) also for 0·43 % NPP than 0·22 % NPP. Supplementation of VD3 enhanced (P<0·05) tibia P retention rate and type III Na-dependent phosphate cotransporter (PiT)-1 protein expression in the duodenum of all broilers. Moreover, VD3 supplementation decreased (P<0·002) mortality and increased (P<0·02) serum P content from the hepatic portal vein after 4 h of feeding, tibia ash content, tibia ash P content and protein expressions of NaP-IIb and PiT-1 in the jejunum of broilers fed diet with 0·22 % NPP. Thus, dietary supplemental VD3 promoted intestinal P absorption and bone P utilisation, and this effect might be associated with enhanced PiT-1 levels in the duodenum and PiT-1 and NaP-IIb levels in the jejunum respectively when dietary NPP is limiting.

Dietary l-threonine supplementation attenuates lipopolysaccharide-induced inflammatory responses and intestinal barrier damage of broiler chickens at an early age.

This study was conducted to investigate the protective effects of l-threonine (l-Thr) supplementation on growth performance, inflammatory responses and intestinal barrier function of young broilers challenged with lipopolysaccharide (LPS). A total of 144 1-d-old male chicks were allocated to one of three treatments: non-challenged broilers fed a basal diet (control group), LPS-challenged broilers fed a basal diet without l-Thr supplementation and LPS-challenged broilers fed a basal diet supplemented with 3·0 g/kg l-Thr. LPS challenge was performed intraperitoneally at 17, 19 and 21 d of age, whereas the control group received physiological saline injection. Compared with the control group, LPS challenge impaired growth performance of broilers, and l-Thr administration reversed LPS-induced increase in feed/gain ratio. LPS challenge elevated blood cell counts related to inflammation, and pro-inflammatory cytokine concentrations in serum (IL-1ß and TNF-α), spleen (IL-1ß and TNF-α) and intestinal mucosa (jejunal interferon-γ (IFN-γ) and ileal IL-1ß). The concentrations of intestinal cytokines in LPS-challenged broilers were reduced by l-Thr supplementation. LPS administration increased circulating d-lactic acid concentration, whereas it reduced villus height, the ratio between villus height and crypt depth and goblet density in both jejunum and ileum. LPS-induced decreases in jejunal villus height, intestinal villus height:crypt depth ratio and ileal goblet cell density were reversed with l-Thr supplementation. Similarly, LPS-induced alterations in the intestinal mRNA abundances of genes related to intestinal inflammation and barrier function (jejunal toll-like receptor 4, IFN- γ and claudin-3, and ileal IL-1 ß and zonula occludens-1) were normalised with l-Thr administration. It can be concluded that l-Thr supplementation could attenuate LPS-induced inflammatory responses and intestinal barrier damage of young broilers.

Serum metabolomics study of nutrient metabolic variations in chronic heat-stressed broilers.

To investigate the effects of heat stress on broiler metabolism, we assigned 144 broilers to normal control (NC), heat stress (HS) or pair-fed (PF) groups and then monitored the effects using growth performance, carcass characteristics, biochemical assays and GC-MS-based metabolomics. The up-regulation of cloacal temperature confirmed that our experiment was successful in inducing chronic heat stress. The average daily gain and average daily feed intake of the HS group were significantly lower than those of the NC group, by 28·76 and 18·42 %, respectively (P1 and P<0·05). The greater feed:gain ratio of the HS group was significantly positively correlated with the leg, abdominal fat, subcutaneous fat and intramuscular fat proportions and levels of some free amino acids (proline, l-cysteine, methionine and threonine) but was negatively correlated with breast proportion and levels of some NEFA (stearic acid, arachidonic acid, palmitic acid and oleic acid). These findings indicated that the heat-stressed broilers were in negative energy balance and unable to effectively mobilise fat, thereby resulting in protein decomposition, which subsequently affected growth performance and carcass characteristics.

[F. G. Yanovsky, the Classic of National Medicine].

In Russia, the elite of therapy took shape in the first decades of XX century. Feofil Gavrilovich Yanovsky, professor of the St. Vladimir Kiev University was one of elite leaders. F. G. Yanovsky, being a classic of national clinical medicine, was renowned for mastery of diagnostics. In particular, it is considered that he was one of first among physicians in Russia who set up an antemortem diagnosis of lung infarction (1902). F. G. Yanovsky was a broad-scoped therapist that is confirmed by his research studies in bacteriology and acute infections, diagnostic, treatment and prevention of tuberculosis, functional diagnostic and treatment of kidney diseases, pathology of digestive organs and blood circulation system, development of techniques of immediate examination of patient and curative preventive application of resort factors. Together with V. P. Obraztsov he was at the head of the third, after the St. Petersburg Military Medical Academy and the Moscow University, Scientific Center of National therapy organized in the St. Vladimir Kiev University. F. G. Yanovsky was the first Soviet clinicians elected as academician of the All-Ukrainian Academy of Science. He established prominent and brilliant clinical school, including such his followers as academicians V. N. Ivanov (Kiev), V. Kh. Vasilenko and B. E. Votchal (Moscow). The exceptional popularity of F. G. Yanovsky was conditioned by especially attractive moral cast of mind of this physician. Ht was Judge of Honor of the Kiev Society of Physicians and he was ready in any time of day and night without a hitch and gratis to treat all needed persons. When F. G. Yanovsky passed away, tenth of thousands of Kiev citizen pay their last tribute to him. All was covered by white lilies and burial service was implemented according Orthodox, Catholic, Protestant and Judaic ceremonies. In Russia, such funeral was not the first one but it became the last one: no more physicians were buried in such a way.

Cytoskeletal remodeling and regulation of cell fate in the hypertensive neonatal pulmonary artery in response to stress.

Neonatal pulmonary hypertension (PHN) is a lethal progressive disease that occurs in prenatal circulatory transition. Mechanical wall strain caused by cardiac pulsation integrates with hypoxia to generate rapidly progressive myocyte cytoskeleton disassembly and failure to exert force generation. The physiological responses to such an interaction have not been investigated. The persistent phenotype does not respond to traditional vasodilator therapy; hence, there is a need for new treatment strategies to improve the morbidity and mortality outcomes. We reviewed the current research methods, models, and markers of persistent PHN relevant to oxidative and nitrosative stress as well as cell fate commitment, with an emphasis on apoptosis and proliferation. We surveyed potential investigations into the role of senescence in neonatal PHN cell fate decision programming during vasodilator treatment and suggested putative drug targets to improve clinical outcomes. We identified important signaling intermediates of senescence and cell cycle entry regulation in hypertensive pulmonary arterial tissues.

Available energy content, nutrients digestibility of chili meal and effects on performance of growing pigs.

The objective of this study was to evaluate the digestible energy (DE), metabolizable energy (ME) content, apparent total tract digestibility (ATTD) of nutrients in chili meal (CM), and to determine the effects of CM on the performance of growing pigs. In Exp. 1, 12 barrows (Duroc x Landrace x Yorkshire) with an initial body weight (BW) of 50.9 ± 1.8 kg were allocated to one of two treatments, corn-soybean meal basal diet or diet containing 194.2 g/kg CM, which replaced corn and soybean meal in the basal diet. Pigs were placed in metabolism crates for a 7-d adaptation period followed by a 5-d total collection of feces and urine to detect DE, ME and ATTD of nutrients in CM. Exp. 2 was conducted for 4 wk. to evaluate the effect of CM on performance of growing pigs. 150 growing pigs (58.4 ± 1.2 kg BW) were allocated to 1 of 5 treatments. Treatment 1 was a corn-soybean meal basal diet met the DE requirement for growing pigs recommended by NRC (2012). Treatment 2 or 3 were diets containing 50 g/kg or 100 g/kg CM respectively. TREATMENT: 4 or 5 were based on treatment 2 or 3, while soybean oil (SBO) was added to improve the DE content to that in treatment 1. In Exp. 1, the DE and ME content of CM were 9.08 and 8.48 MJ/kg. The ATTD of dry matter (DM), gross energy (GE), organic matter (OM) and neutral detergent fiber (NDF) were 0.60, 0.54, 0.66 and 0.38, respectively. In Exp. 2, addition of CM linearly decreased (P < 0.05) average daily gain (ADG) and the ATTD of DM, GE and OM while ATTD of crude protein (CP) had a quadratic (P < 0.05) change. When SBO was supplemented in diets containing CM, greater values (P < 0.05) of ATTD of most nutrients were observed. With the dietary inclusion of CM, the albumin/globulin ratio in serum had a quadratic change (P < 0.05), and the level of low-density cholesterol linearly (P < 0.05) increased. In treatments with 50 g/kg CM, a significant reduction (P < 0.05) of total antioxidant capacity was found in diet formulated with SBO. In treatments with 100 g/kg CM, the level of total cholesterol was lower (P < 0.05) in the diet with SBO. In conclusion, CM had moderate energy density and nutrients digestibility in pig diets. 50 g/kg CM with SBO in diets could be fed to growing pigs with no significant negative effects.

Two new geranylphenylacetate glycosides from the barks of Cinnamomum cassia.

Two new glycosides, cinnacassides F (1) and G (2), with a rare geranylphenylacetate carbon skeleton, were isolated from the barks of Cinnamomum cassia, along with three known analogues, cinnacassides A (3), B (4) and C (5). The structures of the new compounds were elucidated on the basis of extensive NMR spectroscopic analyses and chemical method. Compounds 1-5 were investigated for their immunomodulatory activities, and compounds 1, 3 and 4 showed differential immunosuppressive activities against murine lymphocytes.

Effects of chromium-enriched Bacillus subtilis KT260179 supplementation on growth performance, caecal microbiology, tissue chromium level, insulin receptor expression and plasma biochemical profile of mice under heat stress.

The aim of this study was to investigate the effect of providing supplementary Cr-enriched Bacillus subtilis (CEBS) to mice with regard to their growth performance, caecal microbiology, tissue Cr concentration, insulin receptor (IR) expression and plasma biochemical profile. A total of ninety-six Kunming strain mice were allocated to four different groups: control, CEBS, inorganic Cr and B. subtilis. After 15 d of treatment, mice that received CEBS or normal B. subtilis had higher body weights than control mice, and after 30 d mice given either CEBS or B. subtilis had greater body weights than control mice or those given inorganic Cr. The concentration of Cr in tissues (heart, liver, spleen, kidney and skeletal muscle) increased after CEBS supplementation. B. subtilis and CEBS supplementation caused a significant increase in the numbers of Lactobacillus and Bifidobacterium in the caecum, whereas the numbers of Escherichia coli and Staphylococcus decreased significantly compared with the control. The levels of IR RNA and protein in skeletal muscles increased significantly. Plasma glucose, total cholesterol, TAG and LDL-cholesterol levels declined significantly in the CEBS group compared with the control group, whereas plasma insulin and HDL-cholesterol levels increased significantly. In conclusion, CEBS supplementation enhanced the regulation of body growth, increased tissue organic Cr concentrations, altered caecal microbiota and enhanced IR expression to produce significant changes in plasma biochemistry.

Incorporation of charged residues in the CYP2J2 F-G loop disrupts CYP2J2-lipid bilayer interactions.

CYP2J2 epoxygenase is an extrahepatic, membrane bound cytochrome P450 (CYP) that is primarily found in the heart and mediates endogenous fatty acid metabolism. CYP2J2 interacts with membranes through an N-terminal anchor and various non-contiguous hydrophobic residues. The molecular details of the motifs that mediate membrane interactions are complex and not fully understood. To gain better insights of these complex protein-lipid interactions, we employed molecular dynamics (MD) simulations using a highly mobile membrane mimetic (HMMM) model that enabled multiple independent spontaneous membrane binding events to be captured. Simulations revealed that CYP2J2 engages with the membrane at the F-G loop through hydrophobic residues Trp-235, Ille-236, and Phe-239. To explore the role of these residues, three F-G loop mutants were modeled from the truncated CYP2J2 construct (Δ34) which included Δ34-I236D, Δ34-F239H and Δ34-I236D/F239H. Using the HMMM coordinates of CYP2J2, the simulations were extended to a full POPC membrane which showed a significant decrease in the depth of insertion for each of the F-G loop mutants. The CYP2J2 F-G loop mutants were expressed in E. coli and were shown to be localized to the cytosolic fraction at a greater percentage relative to construct Δ34. Notably, the functional data demonstrated that the double mutant, Δ34-I236D/F239H, maintained native-like enzymatic activity. The membrane insertion characteristics were examined by monitoring CYP2J2 Trp-quenching fluorescence spectroscopy upon binding nanodiscs containing pyrene phospholipids. Relative to the Δ34 construct, the F-G loop mutants exhibited lower Trp quenching and membrane insertion. Taken together, the results suggest that the mutants exhibit a different membrane topology in agreement with the MD simulations and provide important evidence towards the involvement of key residues in the F-G loop of CYP2J2.