Intraperitoneal delivery of a novel drug-like compound improves disease severity in severe and intermediate mouse models of Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder that causes progressive muscle weakness and is the leading genetic cause of infant mortality worldwide. SMA is caused by the loss of survival motor neuron 1 (SMN1). In humans, a nearly identical copy gene is present, called SMN2. Although SMN2 maintains the same coding sequence, this gene cannot compensate for the loss of SMN1 because of a single silent nucleotide difference in SMN2 exon 7. SMN2 primarily produces an alternatively spliced isoform lacking exon 7, which is critical for protein function. SMN2 is an important disease modifier that makes for an excellent target for therapeutic intervention because all SMA patients retain SMN2. Therefore, compounds and small molecules that can increase SMN2 exon 7 inclusion, transcription and SMN protein stability have great potential for SMA therapeutics. Previously, we performed a high throughput screen and established a class of compounds that increase SMN protein in various cellular contexts. In this study, a novel compound was identified that increased SMN protein levels in vivo and ameliorated the disease phenotype in severe and intermediate mouse models of SMA.

Firearm deaths in Sweden.

BACKGROUND: Sweden's firearm legislation obligates physicians to report patients that are deemed unsuitable to possess a firearm. This study aimed to explore the involvement of firearm use in firearm fatalities and to evaluate physician reporting concerning cases of firearm deaths. METHODS: Fatal firearm suicides and homicides in Sweden were studied for the years 2012-2013, accidental deaths and undetermined manner of deaths for the period 1987-2013. Police reports and autopsy protocols were collected from the National Board of Forensic Medicine, health care data in 1 year before the fatality from the National Board of Health, and information about physician reports and firearm licences from the Swedish Police. RESULTS: A total of 291 firearm deaths (213 suicides, 52 accidental deaths, 23 solved homicides and 3 cases with undetermined manner of death) were identified. Firearm suicides were positively correlated with the number of licensed firearm owners. Legal firearm use predominated in firearm suicides and accidental deaths, illegal in homicides. No suicide victim or shooter in an accidental death was previously reported by a physician to the police according to the firearm law. The majority of the shooters in accidental deaths and suicides had no registered health care visits. Less than half (42%) of all suicide victims had a previous health care contact due to mental health problems. CONCLUSIONS: Not one single suicide victim nor any shooter in accidental deaths in the present study had been reported according to the firearm law, bringing the evidence of a suboptimal framework.

The relationship between the MMP system, adrenoceptors and phosphoprotein phosphatases.

The MMPs and their inhibitors [tissue inhibitor of MMPs (TIMPs)] form the mainstay of extracellular matrix homeostasis. They are expressed in response to numerous stimuli including cytokines and GPCR activation. This review highlights the importance of adrenoceptors and phosphoprotein phosphatases (PPP) in regulating MMPs in the cardiovascular system, which may help explain some of the beneficial effects of targeting the adrenoceptor system in tissue remodelling and will establish emerging crosstalk between these three systems. Although α- and ß-adrenoceptor activation increases MMP but decreases TIMP expression, MMPs are implicated in the growth stimulatory effects of adrenoceptor activation through transactivation of epidermal growth factor receptor. Furthermore, they have recently been found to catalyse the proteolysis of ß-adrenoceptors and modulate vascular tone. While the mechanisms underpinning these effects are not well defined, reversible protein phosphorylation by kinases and phosphatases may be key. In particular, PPP (Ser/Thr phosphatases) are not only critical in resensitization and internalization of adrenoceptors but also modulate MMP expression. The interrelationship is complex as isoprenaline (ISO) inhibits okadaic acid [phosphoprotein phosphatase type 1/phosphoprotein phosphatase type 2A (PP2A) inhibitor]-mediated MMP expression. While this may be simply due to its ability to transiently increase PP2A activity, there is evidence for MMP-9 that ISO prevents okadaic acid-mediated expression of MMP-9 through a ß-arrestin, NF-κB-dependent pathway, which is abolished by knock-down of PP2A. It is essential that crosstalk between MMPs, adrenoceptors and PPP are investigated further as it will provide important insight into how adrenoceptors modulate cardiovascular remodelling, and may identify new targets for pharmacological manipulation of the MMP system.

Okadaic acid induces matrix metalloproteinase-9 expression in fibroblasts: crosstalk between protein phosphatase inhibition and ß-adrenoceptor signalling.

BACKGROUND AND PURPOSE: Interactions between protein phosphatase inhibition and matrix metalloproteinase (MMP)-9 expression have implications for tissue remodelling after injury. Stimulation of ß-adrenoceptors could affect such interactions as isoprenaline increases protein phosphatase 2A (PP2A) activity and MMP-9 abundance. We investigated the effect of okadaic acid (OA) on MMP-9 expression to assess interactions between phosphatase inhibition and ß-adrenoceptor signalling in fibroblasts. EXPERIMENTAL APPROACH: Fibroblasts were exposed to OA alone and in combination with isoprenaline. Effects on MMP-9 expression and intracellular signalling were studied using promoter assays, Western blot analysis and siRNA methodologies. KEY RESULTS: Okadaic acid increased MMP-9 abundance in human cardiac ventricular fibroblasts, NIH3T3 fibroblasts and hepatic stellate cells. This effect was unaffected by PP2A knockdown in NIH3T3 cells. OA increased phosphorylation of NF-κB, but not NF-κB promoter activity, IκBα degradation, or nuclear translocation of p65-NF-κB. Exposure to SB202190 (p38 MAPK), U0126 (ERK1/2) and NF-κB III inhibitor revealed that OA induced MMP-9 activity through p38 MAPK. Isoprenaline inhibited OA-mediated MMP-9 expression in NIH3T3, in a ß-arrestin 2- and PP2A-dependent manner. Mutation of the activator protein-1 (AP-1) and NF-κB binding sites demonstrated that OA-induced MMP-9 activity was mediated through the AP-1 but not NF-κB sites. The latter mediated the inhibitory effect of isoprenaline on OA-induced MMP-9 promoter activity. CONCLUSION AND IMPLICATIONS: Okadaic acid induced MMP-9 activity through p38 MAPK and was inhibited by isoprenaline via a pathway involving ß-arrestin 2, PP2A and an NF-κB binding motif. These findings elucidate how phosphoprotein phosphatases and adrenoceptors may modulate tissue remodelling by affecting fibroblast function.

Expression of the stem cell marker nestin in peripheral blood of patients with melanoma.

BACKGROUND: There is continued interest in markers indicative of circulating melanoma cells. Nestin is a neuroepithelial intermediate filament protein that was found to be expressed in melanoma and in various cancer stem cells. OBJECTIVES: We investigated expression of nestin in peripheral blood of patients with melanoma. METHODS: We analysed nestin expression by flow cytometry and by quantitative reverse transcription-polymerase chain reaction both in tissues (n = 23) and in blood samples (n = 102) from patients with American Joint Committee on Cancer stage III-IV melanoma. Forty-six negative controls were also added. RESULTS: Flow cytometry did not reveal nestin-expressing cells in peripheral blood of healthy volunteers. In patients with melanoma, however, nestin protein was expressed in a proportion of melanoma cells enriched from peripheral blood by immunomagnetic sorting. In melanoma tissue samples a significant correlation was found between mRNAs coding for nestin and tyrosinase (P = 0.001) and melan-A (P = 0.002), whereas in blood a significant correlation was observed only for tyrosinase (P = 0.015), but not for melan-A (P = 0.53). Nestin expression was higher in stage IV patients compared with stage III/IV with no evidence of disease, in patients with high tumour burden, and was positively correlated to expression of tyrosinase and melan-A. CONCLUSIONS: Nestin was found to be an additional marker of interest for circulating melanoma cells. Prospective studies should investigate its potential added informative value in comparison with markers already in use for melanoma cell detection.

Potential role of decoy B7-H4 in the pathogenesis of rheumatoid arthritis: a mouse model informed by clinical data.

BACKGROUND: A pathogenic hallmark of rheumatoid arthritis (RA) is persistent inflammatory responses in target tissues and organs. Immune responses mediated by T cells and autoantibodies are known to play pivotal roles. A possible interpretation for this observation is a loss of negative regulation of autoimmune responses. Here we sought to investigate whether B7-H4, a cell surface inhibitory molecule of the B7-CD28 signaling pathway, may play a role in the pathogenesis of RA. METHODS AND FINDINGS: In a cross-sectional study of a clinical convenience sample using monoclonal antibodies against human B7-H4 molecules, we detected high levels of the soluble form of B7-H4 (sH4) in the sera of 65% of patients with RA (n = 68) versus only 13% of healthy donors (n = 24). Elevated sH4 was associated with an increased disease severity score (DAS28) in a cross-sectional analysis. In a mouse model of RA, transgenic expression of sH4 or genetic deletion of B7-H4 accelerated the progression of collagen-induced arthritis, accompanied by enhanced T and B cell-mediated autoimmune responses as well as increased activity of neutrophils. Expression in vivo of an agonist, a B7-H4-immunoglobulin Fc fusion protein, profoundly suppressed disease progression in the mouse model. CONCLUSIONS: Our findings in mice indicate that sH4 acts as a decoy molecule to block the inhibitory functions of cell-surface B7-H4, leading to exacerbation of collagen-induced arthritis. If the preliminary correlation between sH4 levels and disease activity in patients with RA can be confirmed to reflect a similar mechanism, these findings suggest a novel target for treatment approaches. Please see later in the article for the Editors' Summary.

B7-H4-deficient mice display augmented neutrophil-mediated innate immunity.

B7-H4 is an immunoglobulin superfamily molecule and shown to be inhibitory for T-cell responses. To explore physiologic roles of B7-H4, we created B7-H4-deficient (KO) mice by genetic targeting. B7-H4KO mice are healthy and their T- and B-cell responses to polyclonal antigens are in normal range. However, B7-H4KO mice are more resistant to infection by Listeria monocytogenes than their littermates. Within 3 days after infection, bacterial colonies in livers and spleens are significantly lower than the controls, suggesting a role of B7-H4 in enhancing innate immunity. Further studies demonstrate that neutrophils increase in peripheral organs of B7-H4KO mice more so than their littermates but their bactericidal functions remain unchanged. Augmented innate resistance is completely dependent on neutrophils, even in the absence of adaptive immunity. In vitro B7-H4 inhibits the growth of bone marrow-derived neutrophil progenitors, suggesting an inhibitory function of B7-H4 in neutrophil expansion. Our results identify B7-H4 as a negative regulator of the neutrophil response to infection and provide a new target for manipulation of innate immunity.