Sound preconditioning therapy inhibits ototoxic hearing loss in mice

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Abstract

Therapeutic drugs with ototoxic side effects cause significant hearing loss for thousands of patients annually. Two major classes of ototoxic drugs are cisplatin and the aminoglycoside antibiotics, both of which are toxic to mechanosensory hair cells, the receptor cells of the inner ear. A critical need exists for therapies that protect the inner ear without inhibiting the therapeutic efficacy of these drugs. The induction of heat shock proteins (HSPs) inhibits both aminoglycoside- and cisplatin-induced hair cell death and hearing loss. We hypothesized that exposure to sound that is titrated to stress the inner ear without causing permanent damage would induce HSPs in the cochlea and inhibit ototoxic drug–induced hearing loss. We developed a sound exposure protocol that induces HSPs without causing permanent hearing loss. We used this protocol in conjunction with a newly developed mouse model of cisplatin ototoxicity and found that preconditioning mouse inner ears with sound has a robust protective effect against cisplatin-induced hearing loss and hair cell death. Sound therapy also provided protection against aminoglycoside-induced hearing loss. These data indicate that sound preconditioning protects against both classes of ototoxic drugs, and they suggest that sound therapy holds promise for preventing hearing loss in patients receiving these drugs.

Authors

Soumen Roy, Matthew M. Ryals, Astrid Botty Van den Bruele, Tracy S. Fitzgerald, Lisa L. Cunningham

Amelioration of ischemic brain damage by peritoneal dialysis

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Abstract

Ischemic stroke is a devastating condition, for which there is still no effective therapy. Acute ischemic stroke is associated with high concentrations of glutamate in the blood and interstitial brain fluid. The inability of the tissue to retain glutamate within the cells of the brain ultimately provokes neuronal death. Increased concentrations of interstitial glutamate exert further excitotoxic effects on healthy tissue surrounding the infarct zone. We developed a strategy based on peritoneal dialysis to reduce blood glutamate levels, thereby accelerating brain-to-blood glutamate clearance. In a rat model of stroke, this simple procedure reduced the transient increase in glutamate, consequently decreasing the size of the infarct area. Functional magnetic resonance imaging demonstrated that the rescued brain tissue remained functional. Moreover, in patients with kidney failure, peritoneal dialysis significantly decreased glutamate concentrations. Our results suggest that peritoneal dialysis may represent a simple and effective intervention for human stroke patients.

Authors

María del Carmen Godino, Victor G. Romera, José Antonio Sánchez-Tomero, Jesus Pacheco, Santiago Canals, Juan Lerma, José Vivancos, María Angeles Moro, Magdalena Torres, Ignacio Lizasoain, José Sánchez-Prieto

Human antibodies that neutralize respiratory droplet transmissible H5N1 influenza viruses

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Abstract

Recent studies described the experimental adaptation of influenza H5 HAs that confers respiratory droplet transmission (rdt) to influenza virus in ferrets. Acquisition of the ability to transmit via aerosol may lead to the development of a highly pathogenic pandemic H5 virus. Vaccines are predicted to play an important role in H5N1 control should the virus become readily transmissible between humans. We obtained PBMCs from patients who received an A/Vietnam/1203/2004 H5N1 subunit vaccine. Human hybridomas were then generated and characterized. We identified antibodies that bound the HA head domain and recognized both WT and rdt H5 HAs. We used a combination of structural techniques to define a mechanism of antibody recognition of an H5 HA receptor–binding site that neutralized H5N1 influenza viruses and pseudoviruses carrying the HA rdt variants that have mutations near the receptor-binding site. Incorporation or retention of this critical antigenic site should be considered in the design of novel H5 HA immunogens to protect against mammalian-adapted H5N1 mutants.

Authors

Natalie J. Thornburg, David P. Nannemann, David L. Blum, Jessica A. Belser, Terrence M. Tumpey, Shyam Deshpande, Gloria A. Fritz, Gopal Sapparapu, Jens C. Krause, Jeong Hyun Lee, Andrew B. Ward, David E. Lee, Sheng Li, Katie L. Winarski, Benjamin W. Spiller, Jens Meiler, James E. Crowe Jr.

Human skin carcinoma arising from kidney transplant–derived tumor cells

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Abstract

Tumor cells with donor genotype have been identified in human skin cancer after allogeneic transplantation; however, the donor contribution to the malignant epithelium has not been established. Kidney transplant recipients have an increased risk of invasive skin squamous cell carcinoma (SCC), which is associated with accumulation of the tumor suppressor p53 and TP53 mutations. In 21 skin SCCs from kidney transplant recipients, we systematically assessed p53 expression and donor/recipient origin in laser-microdissected p53⁺ tumor cells. In one patient, molecular analyses demonstrated that skin tumor cells had the donor genotype and harbored a TP53 mutation in codon 175. In a kidney graft biopsy performed 7 years before the skin SCC diagnosis, we found p53⁺ cells in the renal tubules. We identified the same TP53 mutation in these p53⁺ epithelial cells from the kidney transplant. These findings provide evidence for a donor epithelial cell contribution to the malignant skin epithelium in the recipient in the setting of allogeneic kidney transplantation. This finding has theoretical implications for cancer initiation and progression and clinical implications in the context of prolonged immunosuppression and longer survival of kidney transplant patients.

Authors

Laurence Verneuil, Mariana Varna, Philippe Ratajczak, Christophe Leboeuf, Louis-François Plassa, Morad Elbouchtaoui, Pierre Schneider, Wissam Sandid, Celeste Lebbé, Marie-Noelle Peraldi, François Sigaux, Hugues de Thé, Anne Janin

Olfm4 deletion enhances defense against Staphylococcus aureus in chronic granulomatous disease

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Abstract

Chronic granulomatous disease (CGD) patients have recurrent life-threatening bacterial and fungal infections. Olfactomedin 4 (OLFM4) is a neutrophil granule protein that negatively regulates host defense against bacterial infection. The goal of this study was to evaluate the impact of Olfm4 deletion on host defense against Staphylococcus aureus and Aspergillus fumigatus in a murine X-linked gp91phox-deficiency CGD model. We found that intracellular killing and in vivo clearance of S. aureus, as well as resistance to S. aureus sepsis, were significantly increased in gp91phox and Olfm4 double-deficient mice compared with CGD mice. The activities of cathepsin C and its downstream proteases (neutrophil elastase and cathepsin G) and serum levels of IL-1β, IL-6, IL-12p40, CXCL2, G-CSF, and GM-CSF in Olfm4-deficient as well as gp91phox and Olfm4 double-deficient mice were significantly higher than those in WT and CGD mice after challenge with S. aureus. We did not observe enhanced defense against A. fumigatus in Olfm4-deficient mice using a lung infection model. These results show that Olfm4 deletion can successfully enhance immune defense against S. aureus, but not A. fumigatus, in CGD mice. These data suggest that OLFM4 may be an important target in CGD patients for the augmentation of host defense against bacterial infection.

Authors

Wenli Liu, Ming Yan, Janyce A. Sugui, Hongzhen Li, Chengfu Xu, Jungsoo Joo, Kyung J. Kwon-Chung, William G. Coleman, Griffin P. Rodgers

Cerebrovascular degradation of TRKB by MMP9 in the diabetic brain

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Abstract

Diabetes elevates the risk for neurological diseases, but little is known about the underlying mechanisms. Brain-derived neurotrophic factor (BDNF) is secreted by microvascular endothelial cells (ECs) in the brain, functioning as a neuroprotectant through the activation of the neurotrophic tyrosine kinase receptor TRKB. In a rat model of streptozotocin-induced hyperglycemia, we found that endothelial activation of MMP9 altered TRKB-dependent trophic pathways by degrading TRKB in neurons. Treatment of brain microvascular ECs with advanced glycation endproducts (AGE), a metabolite commonly elevated in diabetic patients, increased MMP9 activation, similar to in vivo findings. Recombinant human MMP9 degraded the TRKB ectodomain in primary neuronal cultures, suggesting that TRKB could be a substrate for MMP9 proteolysis. Consequently, AGE-conditioned endothelial media with elevated MMP9 activity degraded the TRKB ectodomain and simultaneously disrupted the ability of endothelium to protect neurons against hypoxic injury. Our findings demonstrate that neuronal TRKB trophic function is ablated by MMP9-mediated degradation in the diabetic brain, disrupting cerebrovascular trophic coupling and leaving the brain vulnerable to injury.

Authors

Deepti Navaratna, Xiang Fan, Wendy Leung, Josephine Lok, Shuzhen Guo, Changhong Xing, Xiaoying Wang, Eng H. Lo

Recruited brown adipose tissue as an antiobesity agent in humans

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Abstract

Brown adipose tissue (BAT) burns fat to produce heat when the body is exposed to cold and plays a role in energy metabolism. Using fluorodeoxyglucose-positron emission tomography and computed tomography, we previously reported that BAT decreases with age and thereby accelerates age-related accumulation of body fat in humans. Thus, the recruitment of BAT may be effective for body fat reduction. In this study, we examined the effects of repeated stimulation by cold and capsinoids (nonpungent capsaicin analogs) in healthy human subjects with low BAT activity. Acute cold exposure at 19°C for 2 hours increased energy expenditure (EE). Cold-induced increments of EE (CIT) strongly correlated with BAT activity independently of age and fat-free mass. Daily 2-hour cold exposure at 17°C for 6 weeks resulted in a parallel increase in BAT activity and CIT and a concomitant decrease in body fat mass. Changes in BAT activity and body fat mass were negatively correlated. Similarly, daily ingestion of capsinoids for 6 weeks increased CIT. These results demonstrate that human BAT can be recruited even in individuals with decreased BAT activity, thereby contributing to body fat reduction.

Authors

Takeshi Yoneshiro, Sayuri Aita, Mami Matsushita, Takashi Kayahara, Toshimitsu Kameya, Yuko Kawai, Toshihiko Iwanaga, Masayuki Saito

Atrial natriuretic peptide is negatively regulated by microRNA-425

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Abstract

Numerous common genetic variants have been linked to blood pressure, but no underlying mechanism has been elucidated. Population studies have revealed that the variant rs5068 (A/G) in the 3′ untranslated region of NPPA, the gene encoding atrial natriuretic peptide (ANP), is associated with blood pressure. We selected individuals on the basis of rs5068 genotype (AG vs. AA) and fed them a low- or high-salt diet for 1 week, after which they were challenged with an intravenous saline infusion. On both diets, before and after saline administration, ANP levels were up to 50% higher in AG individuals than in AA individuals, a difference comparable to the changes induced by high-salt diet or saline infusion. In contrast, B-type natriuretic peptide levels did not differ by rs5068 genotype. We identified a microRNA, miR-425, that is expressed in human atria and ventricles and is predicted to bind the sequence spanning rs5068 for the A, but not the G, allele. miR-425 silenced NPPA mRNA in an allele-specific manner, with the G allele conferring resistance to miR-425. This study identifies miR-425 as a regulator of ANP production, raising the possibility that miR-425 antagonists could be used to treat disorders of salt overload, including hypertension and heart failure.

Authors

Pankaj Arora, Connie Wu, Abigail May Khan, Donald B. Bloch, Brandi N. Davis-Dusenbery, Anahita Ghorbani, Ester Spagnolli, Andrew Martinez, Allicia Ryan, Laurel T. Tainsh, Samuel Kim, Jian Rong, Tianxiao Huan, Jane E. Freedman, Daniel Levy, Karen K. Miller, Akiko Hata, Federica del Monte, Sara Vandenwijngaert, Melissa Swinnen, Stefan Janssens, Tara M. Holmes, Emmanuel S. Buys, Kenneth D. Bloch, Christopher Newton-Cheh, Thomas J. Wang

Loss-of-function mutations in SIM1 contribute to obesity and Prader-Willi–like features

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Abstract

Sim1 haploinsufficiency in mice induces hyperphagic obesity and developmental abnormalities of the brain. In humans, abnormalities in chromosome 6q16, a region that includes SIM1, were reported in obese children with a Prader-Willi–like syndrome; however, SIM1 involvement in obesity has never been conclusively demonstrated. Here, SIM1 was sequenced in 44 children with Prader-Willi–like syndrome features, 198 children with severe early-onset obesity, 568 morbidly obese adults, and 383 controls. We identified 4 rare variants (p.I128T, p.Q152E, p.R581G, and p.T714A) in 4 children with Prader-Willi–like syndrome features (including severe obesity) and 4 other rare variants (p.T46R, p.E62K, p.H323Y, and p.D740H) in 7 morbidly obese adults. By assessing the carriers’ relatives, we found a significant contribution of SIM1 rare variants to intra-family risk for obesity. We then assessed functional effects of the 8 substitutions on SIM1 transcriptional activities in stable cell lines using luciferase gene reporter assays. Three mutations showed strong loss-of-function effects (p.T46R, p.H323Y, and p.T714A) and were associated with high intra-family risk for obesity, while the variants with mild or no effects on SIM1 activity were not associated with obesity within families. Our genetic and functional studies demonstrate a firm link between SIM1 loss of function and severe obesity associated with, or independent of, Prader-Willi–like features.

Authors

Amélie Bonnefond, Anne Raimondo, Fanny Stutzmann, Maya Ghoussaini, Shwetha Ramachandrappa, David C. Bersten, Emmanuelle Durand, Vincent Vatin, Beverley Balkau, Olivier Lantieri, Violeta Raverdy, François Pattou, Wim Van Hul, Luc Van Gaal, Daniel J. Peet, Jacques Weill, Jennifer L. Miller, Fritz Horber, Anthony P. Goldstone, Daniel J. Driscoll, John B. Bruning, David Meyre, Murray L. Whitelaw, Philippe Froguel

Whole exome sequencing of adenoid cystic carcinoma

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Abstract

Adenoid cystic carcinoma (ACC) is a rare malignancy that can occur in multiple organ sites and is primarily found in the salivary gland. While the identification of recurrent fusions of the MYB-NFIB genes have begun to shed light on the molecular underpinnings, little else is known about the molecular genetics of this frequently fatal cancer. We have undertaken exome sequencing in a series of 24 ACC to further delineate the genetics of the disease. We identified multiple mutated genes that, combined, implicate chromatin deregulation in half of cases. Further, mutations were identified in known cancer genes, including PIK3CA, ATM, CDKN2A, SF3B1, SUFU, TSC1, and CYLD. Mutations in NOTCH1/2 were identified in 3 cases, and we identify the negative NOTCH signaling regulator, SPEN, as a new cancer gene in ACC with mutations in 5 cases. Finally, the identification of 3 likely activating mutations in the tyrosine kinase receptor FGFR2, analogous to those reported in ovarian and endometrial carcinoma, point to potential therapeutic avenues for a subset of cases.

Authors

Philip J. Stephens, Helen R. Davies, Yoshitsugu Mitani, Peter Van Loo, Adam Shlien, Patrick S. Tarpey, Elli Papaemmanuil, Angela Cheverton, Graham R. Bignell, Adam P. Butler, John Gamble, Stephen Gamble, Claire Hardy, Jonathan Hinton, Mingming Jia, Alagu Jayakumar, David Jones, Calli Latimer, Stuart McLaren, David J. McBride, Andrew Menzies, Laura Mudie, Mark Maddison, Keiran Raine, Serena Nik-Zainal, Sarah O’Meara, Jon W. Teague, Ignacio Varela, David C. Wedge, Ian Whitmore, Scott M. Lippman, Ultan McDermott, Michael R. Stratton, Peter J. Campbell, Adel K. El-Naggar, P. Andrew Futreal