Loss of nuclear poly(A)-binding protein 1 (PABPN1) causes defects in myogenesis and mRNA biogenesis

The nuclear poly(A)-binding protein 1 (PABPN1) is a ubiquitously expressed protein that plays a critical role in polyadenylation. Short expansions of the polyalanine tract in the N-terminus of PABPN1 lead to oculopharyngeal muscular dystrophy (OPMD), which is an adult onset disease characterized by eyelid drooping, difficulty in swallowing and weakness in the proximal limb muscles. Although significant data from in vitro biochemical assays define the function of PABPN1 in control of poly(A) tail length, little is known about the role of PABPN1 in mammalian cells. To assess the function of PABPN1 in mammalian cells and specifically in cells affected in OPMD, we examined the effects of PABPN1 depletion using siRNA in primary mouse myoblasts from extraocular, pharyngeal and limb muscles. PABPN1 knockdown significantly decreased cell proliferation and myoblast differentiation during myogenesis in vitro. At the molecular level, PABPN1 depletion in myoblasts led to a shortening of mRNA poly(A) tails, demonstrating the cellular function of PABPN1 in polyadenylation control in a mammalian cell. In addition, PABPN1 depletion caused nuclear accumulation of poly(A) RNA, revealing that PABPN1 is required for proper poly(A) RNA export from the nucleus. Together, these experiments demonstrate that PABPN1 plays an essential role in myoblast proliferation and differentiation, suggesting that it is required for muscle regeneration and maintenance in vivo.

Anti-inflammatory effect of MAPK phosphatase-1 local gene transfer in inflammatory bone loss

Alveolar bone loss associated with periodontal diseases is the result of osteoclastogenesis induced by bacterial pathogens. The mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) is a critical negative regulator of immune response as a key phosphatase capable of dephosphorylating activated MAPKs. In this study, rat macrophages transduced with recombinant adenovirus (Ad.)MKP-1 specifically dephosphorylated activated MAPKs induced by lipopolysaccharide (LPS) compared with control cells. Bone marrow macrophages from MKP-1 knockout (KO) mice exhibited higher interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, and select chemokine compared with wild-type (WT) mice when stimulated by LPS. In addition, bone marrow cultures from MKP-1 KO mice exhibited significantly more osteoclastogenesis induced by LPS than when compared with WT mice. Importantly, MKP-1 gene transfer in bone marrow cells of MKP-1 KO mice significantly decreased IL-6, IL-10, TNF-α and chemokine levels, and formed fewer osteoclasts induced by LPS than compared with control group of cells. Furthermore, MKP-1 gene transfer in an experimental periodontal disease model attenuated bone resorption induced by LPS. Histological analysis confirmed that periodontal tissues transduced with Ad. MKP-1 exhibited less infiltrated inflammatory cells, less osteoclasts and less IL-6 than compared with rats of control groups. These studies indicate that MKP-1 is a key therapeutic target to control of inflammation-induced bone loss.

Silencing mitogen-activated protein kinase-activated protein kinase-2 arrests inflammatory bone loss

p38 mitogen-activated protein kinases (MAPKs) are critical for innate immune signaling and subsequent cytokine expression in periodontal inflammation and bone destruction. In fact, previous studies show that systemic p38 MAPK inhibitors block periodontal disease progression. However, development of p38 MAPK inhibitors with favorable toxicological profiles is difficult. Here, we report our findings regarding the contribution of the downstream p38 MAPK substrate, mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAPK-2), in immune response modulation in an experimental model of pathogen-derived lipopolysaccharide (LPS)-induced periodontal bone loss. To determine whether small interfering RNA (siRNA) technology has intraoral applications, we initially validated MK2 siRNA specificity. Then, gingival tissue surrounding maxillary molars of rats was injected with MK2 siRNA or scrambled siRNA at the palatal regions of bone loss. Intraoral tissues treated with MK2 siRNA had significantly less MK2 mRNA expression compared with scrambled siRNA-treated tissues. MK2 siRNA delivery arrested LPS-induced inflammatory bone loss, decreased inflammatory infiltrate, and decreased osteoclastogenesis. This proof-of-concept study suggests a novel target using an intraoral RNA interference strategy to control periodontal inflammation.

The H2S-releasing naproxen derivative, ATB-346, inhibits alveolar bone loss and inflammation in rats with ligature-induced periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mineral Loss and Morphological Changes in Dental Enamel Induced by a 16% Carbamide Peroxide Bleaching Gel

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

P300 in individuals with sensorineural hearing loss

INTRODUCTION: Behavioral and electrophysiological auditory evaluations contribute to the understanding of the auditory system and of the process of intervention. OBJECTIVE: To study P300 in subjects with severe or profound sensorineural hearing loss. METHODS: This was a descriptive cross-sectional prospective study. It included 29 individuals of both genders with severe or profound sensorineural hearing loss without other type of disorders, aged 11 to 42 years; all were assessed by behavioral audiological evaluation and auditory evoked potentials. RESULTS: A recording of the P3 wave was obtained in 17 individuals, with a mean latency of 326.97 ms and mean amplitude of 3.76 V. There were significant differences in latency in relation to age and in amplitude according to degree of hearing loss. There was a statistically significant association of the P300 results with the degrees of hearing loss (p = 0.04), with the predominant auditory communication channels (p < 0.0001), and with time of hearing loss. CONCLUSIONS: P300 can be recorded in individuals with severe and profound congenital sensorineural hearing loss; it may contribute to the understanding of cortical development and is a good predictor of the early intervention outcome.

Beyond species loss: the extinction of ecological interactions in a changing world

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

How population loss through habitat boundaries determines the dynamics of a predator-prey system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Loss of desiccation tolerance in Copaifera langsdorffii Desf. seeds during germination

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Intraoperative blood loss and blood transfusion requirements in patients undergoing orthognathic surgery

Procedures for the surgical correction of dentofacial deformities may produce important complications, whether due to the potential for vascular injury or to prolonged surgery, both of which may lead to severe blood loss. Fluid replacement with crystalloid, colloid, or even blood products may be required. The aim of this study was to assess blood loss and transfusion requirements in 45 patients (18 males and 27 females; mean age 29.29 years, range 16-52 years) undergoing orthognathic surgery, assigned to one of two groups according to procedure type-rapid maxillary expansion or double-jaw orthognathic surgery. Preoperative hemoglobin and hematocrit levels and intraoperative blood loss were measured. There was a substantial individual variation in pre- and postoperative hemoglobin values (10.3-17 and 8.8-15.4 g/dL, respectively; p < 0.05). Mean hematocrit values were 41.53 % preoperatively (range 31.3-50.0 %) and 36.56 % postoperatively (range 25-43.8 %) (p < 0.05). Mean blood loss was 274.60 mL (range 45-855 mL). Only two patients required blood transfusion. Although blood loss and transfusion requirements were minimal in the present study, surgical teams should monitor the duration of surgery and follow meticulous protocols to minimize the risks.

Diabetes triggers the loss of tooth structure associated to radiographical and histological dental changes and its evolution to progressive pulp and periapical lesions in rats

The aim of this study was to evaluate the putative influence of diabetes without metabolic control in the loss of tooth structure as well as histological changes in dentin and pulp tissue in rats. Diabetes was induced in Wistar rats (n=25) by intravenous administration of alloxan (42mg/kg). Diabetic and non-diabetic control rats were evaluated at 1, 3, 6, 9 and 12 months of follow-up. In order to evaluate the presence and progression of dental caries and periapical lesions, hemimandibles were removed and submitted to radiographical, histological, and morphometrical procedures. Dental caries were detected after radiographical and histological evaluations in diabetic group from the third month of diabetes onset, increasing gradually in frequency and severity in periods. Diabetic rats dental pulps also presented significant reduction in volume density of collagen fibers and fibroblasts at third month, parallel with a trend towards the increase in inflammatory cells volume density. Diabetic rats presented a generalized pulp tissue necrosis after 6 months of diabetes induction. Moreover, periapical lesions were not detected in control group, while these lesions were observed in all rats after 3, 6, 9, and 12 months of diabetes induction. Uncontrolled diabetes seems to trigger the loss of tooth structure, associated to histological dental changes and mediates its evolution to progressive severe pulp and periapical lesions in rats. Therefore, diabetes may be considered a very important risk factor regarding alterations in dental pulp, development of dental caries, and periapical lesions.

Androgen receptors and experimental bone loss - an in vivo and in vitro study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exenatide and sitagliptin decrease interleukin 1β, matrix metalloproteinase 9, and nitric oxide synthase 2 gene expression but does not reduce alveolar bone loss in rats with periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of avocado/soybean unsaponifiables on ligature-induced bone loss and bone repair after ligature removal in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A comparative, prospective and randomized evaluation of roux-en-y gastric bypass with and without the silastic ring: a 2-year follow up preliminary report on weight loss and quality of life

Currently, Roux-en-Y gastric bypass (RYGB) is one of the most widely used bariatric surgeries. Banding the pouch forms a banded gastric bypass operation, an accepted and frequently used variant. Placing a silastic ring around the pouch to band the gastric bypass operation increases the restriction mechanism. However, the ubiquitous use of the banded gastric bypass remains controversial. One of the controversies is the effect of the silastic ring on patients' perception of their well being after surgery because of the frequency of vomiting. A prospective, blindly randomized, comparative trial was undertaken to resolve this controversy. Four hundred subjects scheduled for gastric bypass surgery were randomized into two arms of the trial, 200 with a silastic ring (WR) and 200 without (NR). After 2-year follow-up, the variables associated with the scores of Bariatric Analysis and Reporting Outcome System (BAROS) were analyzed. The initial median weight (125 kg), BMI (47), and age (36 years) were the same in both the NR and WR groups. The median excess weight loss, weight regain, and incidence of vomiting were 71, 10.5, and 7.75 %, respectively, in the NR group vs. 75.4 and 1.1, and 24.4 % in the WR group. The mean QOL score was 79 % in the NR group vs. 80 % in the WR group. After 2-year follow-up, silastic ring placement in the RYGB resulted in greater weight loss and weight stability and a threefold greater incidence of vomiting. There was no difference in the scores in the quality of life analysis.