Akkermansia muciniphila and its membrane protein ameliorates intestinal inflammatory stress and promotes epithelial wound healing via CREBH and miR-143/145

BACKGROUND

The intestinal epithelial barrier is the interface for interaction between gut microbiota and host metabolic systems. Akkermansia muciniphila (A. muciniphila) is a key player in the colonic microbiota that resides in the mucus layer, whose abundance is selectively decreased in the faecal microbiota of inflammatory bowel disease (IBD) patients. This study aims to investigate the regulatory mechanism among A. muciniphila, a transcription factor cAMP-responsive element-binding protein H (CREBH), and microRNA-143/145 (miR-143/145) in intestinal inflammatory stress, gut barrier integrity and epithelial regeneration.

METHODS

A novel mouse model with increased colonization of A muciniphila in the intestine of CREBH knockout mice, an epithelial wound healing assay and several molecular biological techniques were applied in this study. Results were analysed using a homoscedastic 2-tailed t-test.

RESULTS

Increased colonization of A. muciniphila in mouse gut enhanced expression of intestinal CREBH, which was associated with the mitigation of intestinal endoplasmic reticulum (ER) stress, gut barrier leakage and blood endotoxemia induced by dextran sulfate sodium (DSS). Genetic depletion of CREBH (CREBH-KO) significantly inhibited the expression of tight junction proteins that are associated with gut barrier integrity, including Claudin5 and Claudin8, but upregulated Claudin2, a tight junction protein that enhances gut permeability, resulting in intestinal hyperpermeability and inflammation. Upregulation of CREBH by A. muciniphila further coupled with miR-143/145 promoted intestinal epithelial cell (IEC) regeneration and wound repair via insulin-like growth factor (IGF) and IGFBP5 signalling. Moreover, the gene expressing an outer membrane protein of A. muciniphila, Amuc_1100, was cloned into a mammalian cell-expression vector and successfully expressed in porcine and human IECs. Expression of Amuc_1100 in IECs could recapitulate the health beneficial effect of A. muciniphila on the gut by activating CREBH, inhibiting ER stress and enhancing the expression of genes involved in gut barrier integrity and IEC's regeneration.

CONCLUSIONS

This study uncovers a novel mechanism that links A. muciniphila and its membrane protein with host CREBH, IGF signalling and miRNAs in mitigating intestinal inflammatory stress-gut barrier permeability and promoting intestinal wound healing. This novel finding may lend support to the development of therapeutic approaches for IBD by manipulating the interaction between host genes, gut bacteria and its bioactive components.

Polymorphisms of Fat Mass and Obesity-Associated Gene in the Pathogenesis of Child and Adolescent Metabolic Syndrome

Childhood metabolic syndrome (MetS) is prevalent around the world and is associated with a high likelihood of suffering from severe diseases such as cardiovascular disease later in adulthood. MetS is associated with genetic susceptibility that involves gene polymorphisms. The fat mass and obesity-associated gene (FTO) encodes an RNA N6-methyladenosine demethylase that regulates RNA stability and molecular functions. Human FTO contains genetic variants that significantly contribute to the early onset of MetS in children and adolescents. Emerging evidence has also uncovered that FTO polymorphisms in intron 1, such as rs9939609 and rs9930506 polymorphisms, are significantly associated with the development of MetS in children and adolescents. Mechanistic studies reported that FTO polymorphisms lead to aberrant expressions of FTO and the adjacent genes that promote adipogenesis and appetite and reduce steatolysis, satiety, and energy expenditure in the carriers. The present review highlights the recent observations on the key FTO polymorphisms that are associated with child and adolescent MetS with an exploration of the molecular mechanisms underlying the development of increased waist circumference, hypertension, and hyperlipidemia in child and adolescent MetS.

Abstract 265: Defining Microrna-125 As A Key Determinant In Inflammatory And Mitochondrial Oxidative Stress Of Cardiomyocytes In Myocardial Infarction

MicroRNAs (miRNAs) have been demonstrated to regulate more than 60% of human genes by complementary base pairing between their seed sequences and the targeted mRNAs, resulting in decay and/or translational repression of the mRNAs. A unique mechanistic action of miRNAs is that a single miRNA can simultaneously target a cluster of genes that are involved in functionally associated signalling cascades to generate synergistic impact on cellular process. The objective of this study is to define miR-125a and miR-125b as key determinants in cardiac mitochondrial injury upon myocardial infarction (MI).

Approaches and Results: To this aim, a MI mouse model was established by ligation of the left anterior descending coronary artery. MicroRNA profiling of heart tissues from MI and Sham mice revealed that miR-125a/b were robustly upregulated in the MI hearts. TargetScan analysis identified multiple putative targeting sites of miR-125a/b within the 3’-UTR of genes involved in inflammatory signaling, mitochondrial and endoplasmic reticulum (ER) stress, mitochondrial fusion and fatty acid β-oxidation. These genes include A20 in NFκB-mediated inflammation, ITPR1 in ER calcium channel, PACS2 and MFN1 in mitochondrial membrane remodeling as well as PGC1á/å and PPARα that regulate mitochondrial biogenesis and energy homeostasis. Q-RT-PCR analysis validated the significantly reduced expression of these genes, which confirmed the specific-interaction between miR-125a/b and the genes. Immunoblotting analysis further revealed activation of ER stress in the MI heart, indicated by the activation of ER markers, Grp78 and phosphor-JNK, in the MI cardiomyocytes. The adverse consequences from multiple compromised signalling led to the development of cardiac apoptosis and heart failure. In vitro, exposure the human cardiomyocytes AC16 to hypoxia or Lipopolysaccharides treatment upregulated miR-125a/b expression which was accompanied with impaired mitochondrial biosynthesis and oxidative metabolism, leading to apoptotic cell death.

Conclusion: This novel finding defines miR-125a/b as key regulators of cardiac mitochondrial and ER homeostasis, which may lend support to the development of therapeutic strategy for MI by manipulating miR-125a/b abundance.

Interaction between Sars-CoV-2 structural proteins and host cellular receptors: From basic mechanisms to clinical perspectives

Severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) has caused a global pandemic that has affected the lives of billions of individuals. Sars-CoV-2 primarily infects human cells by binding of the viral spike protein to angiotensin-converting enzyme 2 (ACE2). In addition, novel means of viral entry are currently being investigated, including Neuropillin 1, toll-like receptors (TLRs), cluster of differentiation 147 (CD147), and integrin α5β1. Enriched expression of these proteins across metabolic regulatory organs/tissues, including the circulatory system, liver, pancreas, and intestine contributes to major clinical complications among COVID-19 patients, particularly the development of hypertension, myocardial injury, arrhythmia, acute coronary syndrome and increased coagulation in the circulatory system during and post-infection. Pre-existing metabolic disease, such as cardiovascular disease, obesity, diabetes, and non-alcoholic fatty liver disease, is associated with increased risk of hospitalization, persistent post-infection complications and worse outcomes in patients with COVID-19. This review overviews the biological features of Sars-CoV-2, highlights recent findings that delineate the pathological mechanisms of COVID-19 and the consequent clinical diseases.

Vesical Exclusion

In the operation of vesical exclusion the urine stream is deviated from the urinary bladder into the colon, thereby forming a cloaca, or on to the surface of the skin, where a fistula discharging urine is created.

The operation is indicated in all cases of complete or partial vesical exstrophy. It is successfully employed in treating severe cases of vesico-vaginal fistula, whether the result of obstetric injury or the delayed action of radium.

In carcinoma of the urinary bladder, whether primary or secondary, it is practised, frequently preliminary to the operation of total cystectomy.

In cases of persistent vesical systole and in intractable cystitis, it has also been occasionally done.

The immediate operative mortality following transplantation of the ureters into the pelvic colon is largely dependent on the condition for which the operation is performed. In cases of malignant disease it is high: whereas in conditions that are non-malignant it is a relatively safe procedure.

The establishment of a cloaca, particularly in the female, of itself produces no appreciable disability. If the operation has been performed for a congenital or an acquired deformity, and this has been skilfully and successfully carried out and the patient has become stabilized, the expectancy of life should not be appreciably diminished.

The case of a patient, upon whom the operation had been performed twenty-nine years previously, is reviewed and particulars of others in which it was performed fourteen years ago, or later, are referred to.

In the pre-operative preparation, in addition to the usual thorough clinical investigation, an examination by excretion urography is indicated, especially to determine the possible presence of a third ureter or a single functioning kidney. At this period it is also important, particularly in cases of obstetric injury, to be sure that the rectal sphincter is fully competent and that no hæmorrhoids are present.

The operative technique was carried out under twilight sleep and spinal anæsthesia. The vital importance of careful post-operative treatment is emphasized. By the immediate post-operative administration of sodium sulphate, by intravenous injection and attention to other details, bilateral ureteral transplantation carried out in one stage could be safely embarked upon without the fear of anuria developing.

A detailed record of 60 cases, in which the operation of vesical exclusion has been carried out by the author is given.

Toward the de novo design of a catalytically active helix bundle: a substrate-accessible carboxylate-bridged dinuclear metal center

De novo design of proteins provides an attractive approach to uncover the essential features required for their functions. Previously, we described the design and crystal structure determination of a di-Zn(II) complex of "due-ferri-1" (DF1), a protein patterned after the diiron-dimanganese class of redox-active proteins [Lombardi, A.; Summa, C.; Geremia, S.; Randaccio, L.; Pavone, V.; DeGrado, W. F. Proc. Natl. Acad. Sci. U.S.A. 2000, 97, 6298-6305]. The overall structure of DF1, which contains a carboxylate-bridged dinuclear metal site, agrees well with the intended design. However, access to this dimetal site is blocked by a pair of hydrophobic leucine residues (L13 and L13'), which prevent facile entry of metal ions and small molecules. We have now taken the next step in the eventual construction of a catalytically active metalloenzyme by engineering an active site cavity into DF1 through the replacement of these two leucine residues with smaller residues. The crystal structure of the dimanganous form of L13A-DF1 indeed shows a substrate access channel to the dimetal center. In the crystal structure, water molecules and a ligating dimethyl sulfoxide molecule, which forms a monatomic bridge between the metal ions, occupy the cavity. Furthermore, the diferric form of a derivative of L13A-DF1, DF2, is shown to bind azide, acetate, and small aromatic molecules.

The structural and functional basis of antibody catalysis

Ten years have passed since the initial reports that antibodies could be programmed to have enzymatic activity by immunization with a transition-site analog. Much of the research over the last decade has focused on defining the scope and generality of antibody catalysis; however, during the past two years the first few crystal structures of catalytic antibody transition-state analogs have been reported. This review analyzes four such structures of catalytic antibodies that catalyze markedly different reactions, including ester hydrolysis, sulfide oxidation, and a pericyclic rearrangement. Structure-function relations for these catalysts are discussed and compared to the structure and function of natural enzymes, as well as the chemistry that occurs in solution.

A controlled study of luteinizing hormone-releasing hormone agonist (buserelin) for the induction of folliculogenesis before in vitro fertilization

Treatment with clomiphene citrate and human menopausal gonadotropin (HMG) is often used to induce folliculogenesis before in vitro fertilization, but not all women have an adequate response. It has been hypothesized that abnormally high levels of luteinizing hormone (LH) may contribute to the reduced folliculogenesis. We therefore performed a controlled, open trial in which treatment with buserelin, an agonist of luteinizing hormone-releasing hormone citrate and HMG in 44 consecutive women in whom no oocytes or only one had been produced by standard treatment with clomiphene and HMG. Twenty-nine women received buserelin with HMG, and 15 received clomiphene citrate with HMG. The median number of oocytes per patient recovered from those who received buserelin with HMG was 4 (range, 0 to 19), as compared with 0 (range, 0 to 5) in those who received clomiphene citrate with HMG. The fertilization rates of oocytes recovered from both groups of patients were similar (75.8 percent and 76.5 percent, respectively). Fifty-four percent of patients given buserelin with HMG underwent triple-embryo transfer, as compared with 13 percent of those given clomiphene citrate with HMG. Pregnancy (n = 3) occurred only among the patients receiving buserelin with HMG. In the buserelin-HMG group, significantly fewer oocytes were recovered from patients with occult ovarian failure (infertility and elevated follicular-phase levels of follicle-stimulating hormone, with regular menses) (median, 1; range, 0 to 4) than from those with other causes of infertility (median, 8; range, 0 to 19). Our data suggest that, except in women with occult ovarian failure, buserelin and HMG improve embryologic and clinical outcomes in patients with previously unsatisfactory stimulation of the ovaries for in vitro fertilization.

The treatment and preoperative diagnosis of differentiated thyroid carcinoma presenting as a clinically solitary nodule

Some papillary and follicular carcinomas of the thyroid present as solitary nodules with no clinical or radiological evidence of metastases. The elective treatment of such early thyroid carcinomas is discussed, with particular reference to the surgical approach to the clinically solitary nodule. The investigations available for establishing a preoperative diagnosis of the pathology of a solitary nodule are also discussed. A high degree of accuracy is obtainable but absolute certainty, only occasionally. If doubt exists, the safe treatment is excision of the nodule and frozen section.

Solitary thyroid nodule

The pathological conditions responsible for a truly solitary thyroid nodule are discussed and a policy of management is outlined for a patient who presents with a clinically solitary nodule. Sophisticated methods of investigation and treatment, while often helpful, are not essential. Scanning is not a highly accurate diagnostic tool, and the solitary nodule can be treated effectively without frozen section or isotopes. The incidence of unsuspected carcinoma in a solitary nodule in a euthyroid patient is high enough to justify exploration in all cases in which the patient is fit for surgery.

Vesical Exclusion: (Section of Urology)

In the operation of vesical exclusion the urine stream is deviated from the urinary bladder into the colon, thereby forming a cloaca, or on to the surface of the skin, where a fistula discharging urine is created.The operation is indicated in all cases of complete or partial vesical exstrophy. It is successfully employed in treating severe cases of vesico-vaginal fistula, whether the result of obstetric injury or the delayed action of radium.In carcinoma of the urinary bladder, whether primary or secondary, it is practised, frequently preliminary to the operation of total cystectomy.In cases of persistent vesical systole and in intractable cystitis, it has also been occasionally done.The immediate operative mortality following transplantation of the ureters into the pelvic colon is largely dependent on the condition for which the operation is performed. In cases of malignant disease it is high: whereas in conditions that are non-malignant it is a relatively safe procedure.The establishment of a cloaca, particularly in the female, of itself produces no appreciable disability. If the operation has been performed for a congenital or an acquired deformity, and this has been skilfully and successfully carried out and the patient has become stabilized, the expectancy of life should not be appreciably diminished.The case of a patient, upon whom the operation had been performed twenty-nine years previously, is reviewed and particulars of others in which it was performed fourteen years ago, or later, are referred to.In the pre-operative preparation, in addition to the usual thorough clinical investigation, an examination by excretion urography is indicated, especially to determine the possible presence of a third ureter or a single functioning kidney. At this period it is also important, particularly in cases of obstetric injury, to be sure that the rectal sphincter is fully competent and that no haemorrhoids are present.The operative technique was carried out under twilight sleep and spinal anaesthesia. The vital importance of careful post-operative treatment is emphasized. By the immediate post-operative administration of sodium sulphate, by intravenous injection and attention to other details, bilateral ureteral transplantation carried out in one stage could be safely embarked upon without the fear of anuria developing.A detailed record of 60 cases, in which the operation of vesical exclusion has been carried out by the author is given.

The Treatment of Malignant Disease of the Urinary Bladder

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