Microbial Symbionts Accelerate Wound Healing via the Neuropeptide Hormone Oxytocin

Wound healing capability is inextricably linked with diverse aspects of physical fitness ranging from recovery after minor injuries and surgery to diabetes and some types of cancer. Impact of the microbiome upon the mammalian wound healing process is poorly understood. We discover that supplementing the gut microbiome with lactic acid microbes in drinking water accelerates the wound-healing process to occur in half the time required for matched control animals. Further, we find that Lactobacillus reuteri enhances wound-healing properties through up-regulation of the neuropeptide hormone oxytocin, a factor integral in social bonding and reproduction, by a vagus nerve-mediated pathway. Bacteria-triggered oxytocin serves to activate host CD4+Foxp3+CD25+ immune T regulatory cells conveying transplantable wound healing capacity to naive Rag2-deficient animals. This study determined oxytocin to be a novel component of a multi-directional gut microbe-brain-immune axis, with wound-healing capability as a previously unrecognized output of this axis. We also provide experimental evidence to support long-standing medical traditions associating diet, social practices, and the immune system with efficient recovery after injury, sustained good health, and longevity.     

Pertussis toxin as a probe of neutrophil activation

In reviewing our own and other work, it is clear that pertussis toxin treatment of neutrophils causes a time- and concentration-dependent inhibition of granule enzyme secretion induced by formylmethionylleucylphenylalanine (fMet-Leu-Phe), C5a, leukotriene (LT) B4 and platelet-activating factor (PAF). Chemotaxis, O2- generation, aggregation, and arachidonic acid production induced by fMet-Leu-Phe are also inhibited by pertussis toxin. Granule enzyme release caused by A23187 or phorbol 12-myristate 13-acetate is not inhibited. The inhibition of neutrophil function correlates closely with the NAD-ribosylation of a 41,000-dalton protein in the neutrophil plasma membrane, presumably the GTP-binding regulatory protein Ni. Pertussis toxin treatment prevents or obtunds the increased influx of Ca2+ induced by fMet-Leu-phe and LTB4, but not that caused by stimulation of neutrophils with PAF. Pertussis toxin prevents the receptor-induced breakdown of polyphosphoinositides in intact neutrophils and isolated membrane and prevents or decreases the production of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol. The hypothesis advanced by us and others is that pertussis toxin interacts with a GTP-binding regulatory protein identical or similar to Ni, which couples receptor-chemotactic factor interaction to phospholipase C activation. Inhibition of the activation prevents the production of IP3 and the resulting release of Ca2+ from intracellular stores and of 1,2-diacylglycerol and thus, the activation of protein kinase C. The lack of these two mediators is the immediate cause of the depression of neutrophil activation resulting from pertussis toxin. Some of the limitations and uncertainties of our present knowledge with respect to this hypothesis are discussed.     

Is a rise in intracellular concentration of free calcium necessary or sufficient for stimulated cytoskeletal-associated actin?

The addition of the calcium ionophore A23187 to rabbit neutrophils increases the amount of actin associated with the cytoskeleton regardless of the presence or absence of calcium in the incubation medium. In the presence of extracellular calcium, the effect of A23187 is biphasic with respect to concentration. The action of the ionophore is rapid, transient, and is inhibited by pertussis toxin, hyperosmolarity, and quinacrine. On the other hand, the addition of pertussis toxin or hyperosmolarity has small if any, effect on the rise in intracellular calcium produced by A23187. While quinacrine does not affect the fMet-Leu-Phe-induced increase in cytoskeletal actin and the polyphosphoinositide turnover, its addition inhibits completely the stimulated increase in Ca-influx produced by the same stimulus. The results presented here suggest that a rise in the intracellular concentration of free calcium is neither necessary nor sufficient for the stimulated increase in cytoskeletal-associated actin. A possible relationship between the lipid remodeling stimulated by chemoattractants and the increased cytoskeletal actin is discussed.     

The inhibition of neutrophil granule enzyme secretion and chemotaxis by pertussis toxin

Pertussis toxin treatment of rabbit peritoneal neutrophils causes a concentration-dependent inhibition of granule enzyme secretion induced by formylmethionyl-leucyl-phenylalanine, C5a, and leukotriene B4. It also inhibits chemotaxis induced by formylmethionyl-leucyl-phenylalanine. The same toxin treatment, however, has no effect on granule enzyme secretion induced by the calcium ionophore A23187 or phorbol 12-myristate 13-acetate. Moreover, pertussis toxin treatment does not affect either the number or affinity of the formylpeptide receptors on the neutrophil nor does it have any effect on the unstimulated levels of cyclic AMP (cAMP) or the transient rise in cAMP induced by chemotactic factor stimulation in these cells. We hypothesize that pertussis toxin, as in other cells, interacts with a GTP binding regulatory protein identical with or analogous to either Ni or transducin which mediates the receptor-induced inhibition or activation of a target protein or proteins required in neutrophil activation. The nature of the target protein is unknown, but it is not the catalytic unit of adenylate cyclase. The target protein acts after binding of chemotactic factor to its receptor in the sequence that leads to the receptor-induced rise in intracellular Ca2+. It does not affect the responses elicited by the direct introduction of calcium into the cells or the activity of protein kinase C.     

Chemotactic factor causes rapid decreases in phosphatidylinositol,4,5-bisphosphate and phosphatidylinositol 4-monophosphate in rabbit neutrophils

Stimulation of rabbit neutrophils prelabeled with 32P by the synthetic chemotactic peptide f-Met-Leu-Phe induces a rapid decrease in the radioactivity in both phosphatidylinositol, 4,5 bis phosphate and phosphatidylinositol 4-monophosphate. The mean +/- standard error of the mean values of the maximum decrease in phosphatidylinositol, 4,5 bis phosphate occurred at 10 seconds following stimulation and is equal to 19 +/- 3% of the control value. The corresponding value for phosphatidylinositol 4-monophosphate occurred at 60 seconds following stimulation and is equal to 37 +/- 7% of the control value. On the other hand, the radioactivity in phosphatidic acid and lysophospholipids increased continuously with time following stimulation. The relationship of these changes to calcium release and neutrophil activation is discussed.     

Immunological and chemical characterization of hamster brain polyribosomes-cytomatrix complexes

We have studied the cytoskeletal nature of a brain subcellular fraction previously shown to contain polyribosomes. We have identified the major proteins of this fraction by electrophoretic comparison to a standard cytoskeletal fraction and by immunodetection. These methods have shown the presence of actin, glial fibrillary acidic protein, and neurofilament triplet proteins. We have also studied the effect of various ions and nonionic detergents on the stability of this structure. It was stable in presence of Triton X-100 up to 2% but disrupted by 200 mM K⁺ acetate.Abbreviations CMT cytomatrix - CSK cytoskeleton - DOC sodium deoxycholate - DTT dithiothreitol - EGTA ethylenglycolbis (-Ether)-N,N-N-N-Tetraacetic Acid - GFAP glial fibrillary acidic protein - PR polyribosome - PRCMC polyribosomes-cytomatrix complex     

Aptamer-functionalized quantum dots as theranostic nanotools against cancer and bacterial infections: A comprehensive overview of recent trends

Aptamers (Apts) are synthetic nucleic acid ligands that can be engineered to target various molecules, including amino acids, proteins, and pharmaceuticals. Through a series of adsorption, recovery, and amplification steps, Apts are extracted from combinatorial libraries of synthesized nucleic acids. Using aptasensors in bioanalysis and biomedicine can be improved by combining them with nanomaterials. Moreover, Apt-associated nanomaterials, including liposomes, polymeric, dendrimers, carbon nanomaterials, silica, nanorods, magnetic NPs, and quantum dots (QDs), have been widely used as promising nanotools in biomedicine. Following surface modifications and conjugation with appropriate functional groups, these nanomaterials can be successfully used in aptasensing. Advanced biological assays can use Apts immobilized on QD surfaces through physical interaction and chemical bonding. Accordingly, modern QD aptasensing platforms rely on interactions between QDs, Apts, and targets to detect them. QD-Apt conjugates can be used to directly detect prostate, ovarian, colorectal, and lung cancers or simultaneously detect biomarkers associated with these malignancies. Tenascin-C, mucin 1, prostate-specific antigen, prostate-specific membrane antigen, nucleolin, growth factors, and exosomes are among the cancer biomarkers that can be sensitively detected using such bioconjugates. Furthermore, Apt-conjugated QDs have shown great potential for controlling bacterial infections such as Bacillus thuringiensis, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Campylobacter jejuni, Staphylococcus aureus, and Salmonella typhimurium. This comprehensive review discusses recent advancements in the design of QD-Apt bioconjugates and their applications in cancer and bacterial theranostics.     

ARRHYTHMIA WITH MITRAL VALVE PROLAPSE: RESULTS OF ANNULOPLASTY IN TWO PATIENTS

The effectiveness of posterior annuloplasty in two patients who failed to respond to medical treatment for atrial and ventricular arrhythmias related to mitral valve prolapse (MVP) is reported. Although the etiology of arrhythmia in MVP remains mostly speculative, anatomic correction of prolapse or billowing of the mitral leaflets appears to reverse the anatomic and pathologic conditions that cause the arrhythmia.     

Reconstitution and partial purification of the glibenclamide-sensitive, ATP-dependent K+ channel from rat liver and beef heart mitochondria.

The transport properties of mitochondria are such that net potassium flux across the inner membrane determines mitochondrial volume. It has been known that K+ uptake is mediated by diffusive leak driven by the high electrical membrane potential maintained by redox-driven, electrogenic proton ejection and that regulated K+ efflux is mediated by an 82-kDa inner membrane K+/H+ antiporter. There is also long-standing suggestive evidence for the existence of an inner membrane protein designed to catalyze electrophoretic K+ uptake into mitochondria. We report reconstitution of a highly purified inner membrane protein fraction from rat liver and beef heart mitochondria that catalyzes electrophoretic K+ flux in liposomes and channel activity in planar lipid bilayers. The unit conductance of the channel at saturating [K+] is about 30 pS. Reconstituted K+ flux is inhibited with high affinity by ATP and ADP in the presence of divalent cations and by glibenclamide in the absence of divalent cations. The mitochondrial ATP-dependent K+ channel is selective for K+, with a Km of 32 mM, and does not transport Na+. K+ transport depends on voltage in a manner consistent with a channel activity that is not voltage-regulated. Thus, the mitochondrial ATP-dependent K+ channel exhibits properties that are remarkably similar to those of the ATP-dependent K+ channels of plasma membranes.