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1.
Ann Plast Surg ; 92(4): 389-394, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38527344

RESUMO

BACKGROUND: Collagenase clostridium histolyticum (collagenase) was introduced in 2010 creating a nonoperative treatment option for Dupuytren disease with promising results in sponsored clinical trials. A meta-analysis was performed to investigate industry sponsorship bias. METHODS: A systematic review of collagenase treatment of Dupuytren contracture was conducted. Articles containing mesh terms including "microbial collagenase" and "Dupuytren's contracture" were searched and limited to only clinical trials with similar protocols for inclusion. Meta-analysis of treatment endpoints of correction of contracture to 0-5 degrees after first and last injection was conducted comparing sponsored versus nonsponsored studies. RESULTS: Sixteen of the 29 identified articles met criteria for inclusion. Nonsponsored studies reported a significantly higher rate of meeting the primary treatment endpoint compared to sponsored studies after single injection for all joints (69.6% vs 56% P < 0.01), metacarpophalangeal joint (96% vs 64% P < 0.01), and proximal interphalangeal joint (67% vs 36% P = 0.011). The correction in contracture rates was similar between groups with studies evaluating more than one injection. CONCLUSIONS: Nonsponsored studies published higher success rates in meeting the primary endpoint of full correction after single injection than sponsored studies; however, similar results with multiple injections. This study demonstrated that sponsored studies of collagenase produced highly powered studies that may be reliably depended on for evidence-based clinical application.


Assuntos
Contratura de Dupuytren , Humanos , Contratura de Dupuytren/tratamento farmacológico , Resultado do Tratamento , Injeções Intralesionais , Colagenase Microbiana/uso terapêutico
2.
Front Cell Dev Biol ; 10: 790410, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35252171

RESUMO

Triple negative breast cancer (TNBC) follows a non-random pattern of metastasis to the bone and brain tissue. Prior work has found that brain-seeking breast tumor cells display altered proteomic profiles, leading to alterations in pathways related to cell signaling, cell cycle, metabolism, and extracellular matrix remodeling. Given the unique microenvironmental characteristics of brain and bone tissue, we hypothesized that brain- or bone-seeking TNBC cells may have altered morphologic or migratory phenotypes from each other, or from the parental TNBC cells, as a function of the biochemical or mechanical microenvironment. In this study, we utilized TNBC cells (MDA-MB-231) that were conditioned to metastasize solely to brain (MDA-BR) or bone (MDA-BO) tissue. We quantified characteristics such as cell morphology, migration, and stiffness in response to cues that partially mimic their final metastatic niche. We have shown that MDA-BO cells have a distinct protrusive morphology not found in MDA-P or MDA-BR. Further, MDA-BO cells migrate over a larger area when on a collagen I (abundant in bone tissue) substrate when compared to fibronectin (abundant in brain tissue). However, migration in highly confined environments was similar across the cell types. Modest differences were found in the stiffness of MDA-BR and MDA-BO cells plated on collagen I vs. fibronectin-coated surfaces. Lastly, MDA-BO cells were found to have larger focal adhesion area and density in comparison with the other two cell types. These results initiate a quantitative profile of mechanobiological phenotypes in TNBC, with future impacts aiming to help predict metastatic propensities to organ-specific sites in a clinical setting.

3.
PLoS Pathog ; 18(1): e1010159, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34995322

RESUMO

The clinical impact of rhinovirus C (RV-C) is well-documented; yet, the viral life cycle remains poorly defined. Thus, we characterized RV-C15 replication at the single-cell level and its impact on the human airway epithelium (HAE) using a physiologically-relevant in vitro model. RV-C15 replication was restricted to ciliated cells where viral RNA levels peaked at 12 hours post-infection (hpi), correlating with elevated titers in the apical compartment at 24hpi. Notably, infection was associated with a loss of polarized expression of the RV-C receptor, cadherin-related family member 3. Visualization of double-stranded RNA (dsRNA) during RV-C15 replication revealed two distinct replication complex arrangements within the cell, likely corresponding to different time points in infection. To further define RV-C15 replication sites, we analyzed the expression and colocalization of giantin, phosphatidylinositol-4-phosphate, and calnexin with dsRNA. Despite observing Golgi fragmentation by immunofluorescence during RV-C15 infection as previously reported for other RVs, a high ratio of calnexin-dsRNA colocalization implicated the endoplasmic reticulum as the primary site for RV-C15 replication in HAE. RV-C15 infection was also associated with elevated stimulator of interferon genes (STING) expression and the induction of incomplete autophagy, a mechanism used by other RVs to facilitate non-lytic release of progeny virions. Notably, genetic depletion of STING in HAE attenuated RV-C15 and -A16 (but not -B14) replication, corroborating a previously proposed proviral role for STING in some RV infections. Finally, RV-C15 infection resulted in a temporary loss in epithelial barrier integrity and the translocation of tight junction proteins while a reduction in mucociliary clearance indicated cytopathic effects on epithelial function. Together, our findings identify both shared and unique features of RV-C replication compared to related rhinoviruses and define the impact of RV-C on both epithelial cell organization and tissue functionality-aspects of infection that may contribute to pathogenesis in vivo.


Assuntos
Retículo Endoplasmático/virologia , Enterovirus/fisiologia , Mucosa Respiratória/virologia , Replicação Viral/fisiologia , Células Cultivadas , Efeito Citopatogênico Viral/fisiologia , Humanos
4.
Artigo em Inglês | MEDLINE | ID: mdl-34594458

RESUMO

Discussion can be an important and powerful tool in efforts to build a more diverse, equitable, and inclusive future for STEM (i.e., science, technology, engineering, and mathematics). However, facilitating discussions on difficult, complex, and often uncomfortable issues, like racism and sexism, can feel daunting. We outline a series of steps that can be used by educators to facilitate productive discussions that empower everyone to listen, contribute, learn, and ultimately act to transform STEM.

5.
Artigo em Inglês | MEDLINE | ID: mdl-33519171

RESUMO

The blood-brain barrier (BBB) remains a major obstacle for drug delivery to the central nervous system. In particular, the tight and adherens junctions that join the brain capillary endothelial cells limit the diffusion of various molecules from the bloodstream into the brain. Photodynamic priming (PDP) is a non-cytotoxic modality that involves light activation of photosensitizers to photochemically modulate nearby molecules without killing the cells. Here we investigate the effects of sub-lethal photochemistry on junction phenotype (i.e., continuous, punctate, or perpendicular), as well as the BBB permeability in a transwell model of human brain microvascular endothelial cells (HBMECs). We showed that PDP decreases the continuous junction architecture by ~20%, increases the perpendicular junction architecture by ~40%, and has minimal impact on cell morphology in HBMECs. Furthermore, transwell permeability assay revealed that PDP improves the HBMEC permeability to dextran or nanoliposomes by up to 30-fold for 6-9 days. These results suggest that PDP could safely reverse the mature brain endothelial junctions without killing the HBMECs. This study not only emphasizes the critical roles of PDP in the modulation junction phenotype, but also highlights the opportunity to further develop PDP-based combinations that opens the cerebrum endothelium for enhanced drug transporter across the BBB.

6.
J Burn Care Res ; 42(3): 465-472, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33091131

RESUMO

Vascularized composite allotransplantation has been successfully employed for burn reconstruction since 2003. However, its safety in this population has been questioned due to high levels of alloimmunization from burn care-related tissue exposures. To investigate this, a systematic review of vascularized composite allotransplantation employed for burn reconstruction was conducted, evaluating literature from January 2000 to September 2019. Articles containing vascularized composite allotransplantation, composite tissue allotransplantation, and burn reconstructive surgery were included; articles without published outcomes were excluded. Observational meta-analysis of pooled mortality and acute rejection episodes relative to allograft type (face vs extremity) and reconstruction type (burn vs non-burn) was performed. Twenty-four of the 63 identified articles met the criteria for inclusion, with 5 more articles added after secondary review. To date, 152 allotransplantations have been performed in 117 patients: 45 face transplants and 107 extremity transplants. Of these, 34 (22%) were performed for burn reconstruction in 25 patients (21%) with an overall higher 1-year mortality rate (12.0% vs 1.1%, P = .030). Of these deaths, 75% received three or more simultaneous allografts. Additionally, more episodes of acute rejection occurred compared to non-burn patients (4.4 vs 2.4, P = .035). Vascularized composite allotransplantation performed for burn reconstruction was found to be associated with a greater risk of 1-year mortality and nearly twice the number of episodes of acute rejection. Future studies should seek to identify unique risk factors of burn patients undergoing this operation and evaluate the relationship between antigenic burden and surgical outcomes.


Assuntos
Queimaduras/cirurgia , Alotransplante de Tecidos Compostos Vascularizados , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos
7.
IDCases ; 20: e00784, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32420030

RESUMO

Clostridium septicum is an anaerobic, gram-positive bacillus known to cause myonecrosis, also known as gas gangrene, a life-threatening necrotizing soft tissue infection. Though it accounts for just 1 % of all infections attributable to Clostridia spp., C. septicum is a highly virulent and aggressive pathogen. Classic presentations of infection include bacteremia resulting in shock, myonecrosis, and vascular seeding. C. septicum-associated gas gangrene most commonly occurs in the setting of traumatic injury, but has also been reported in patients with colorectal malignancy, immunosuppression, neutropenia, and exceedingly rare in association with breast cancer. We report the case of a 56-year-old female patient with stage IV mixed lobar and ductal breast carcinoma with metastasis to the bone and liver, who presented with spontaneous C. septicum myonecrosis of the right hand. No prior traumatic injury was noted. Following amputation of the right forearm, antibiotic treatment, and multiorgan support, the patient passed following transition to palliative care. We hope to increase awareness of this relatively uncommon, though potentially deadly pathogen, as well as to discuss treatment options in patients infected with C. septicum.

8.
Fluids Barriers CNS ; 17(1): 16, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32046757

RESUMO

BACKGROUND: The endothelial cell-cell junctions of the blood-brain barrier (BBB) play a pivotal role in the barrier's function. Altered cell-cell junctions can lead to barrier dysfunction and have been implicated in several diseases. Despite this, the driving forces regulating junctional protein presentation remain relatively understudied, largely due to the lack of efficient techniques to quantify their presentation at sites of cell-cell adhesion. Here, we used our novel Junction Analyzer Program (JAnaP) to quantify junction phenotype (i.e., continuous, punctate, or perpendicular) in response to various substrate compositions, cell culture times, and cAMP treatments in human brain microvascular endothelial cells (HBMECs). We then quantitatively correlated junction presentation with barrier permeability on both a "global" and "local" scale. METHODS: We cultured HBMECs on collagen I, fibronectin, collagen IV, laminin, fibronectin/collagen IV/laminin, or hyaluronic acid/gelatin for 2, 4, and 7 days with varying cAMP treatment schedules. Images of immunostained ZO-1, VE-cadherin, and claudin-5 were analyzed using the JAnaP to calculate the percent of the cell perimeter presenting continuous, punctate, or perpendicular junctions. Transwell permeability assays and resistance measurements were used to measure bulk ("global") barrier properties, and a "local" permeability assay was used to correlate junction presentation proximal to permeable monolayer regions. RESULTS: Substrate composition was found to play little role in junction presentation, while cAMP supplements significantly increased the continuous junction architecture. Increased culture time required increased cAMP treatment time to reach similar ZO-1 and VE-cadherin coverage observed with shorter culture, though longer cultures were required for claudin-5 presentation. Prolonged cAMP treatment (6 days) disrupted junction integrity for all three junction proteins. Transwell permeability and TEER assays showed no correlation with junction phenotype, but a local permeability assay revealed a correlation between the number of discontinuous and no junction regions with barrier penetration. CONCLUSIONS: These results suggest that cAMP signaling influences HBMEC junction architecture more than matrix composition. Our studies emphasized the need for local barrier measurement to mechanistically understand the role of junction phenotype and supported previous results that continuous junctions are indicative of a more mature/stable endothelial barrier. Understanding what conditions influence junction presentations, and how they, in turn, affect barrier integrity, could lead to the development of therapeutics for diseases associated with BBB dysfunction.


Assuntos
Barreira Hematoencefálica/metabolismo , Células Endoteliais/metabolismo , Junções Intercelulares/metabolismo , Fenótipo , Encéfalo/metabolismo , Adesão Celular/fisiologia , Células Cultivadas , Fibronectinas/metabolismo , Humanos , Permeabilidade , Junções Íntimas/metabolismo
9.
Cell Mol Bioeng ; 12(3): 215-226, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31719911

RESUMO

INTRODUCTION: The mechanical interaction between cells and their microenvironment is emerging as an important determinant of cancer progression and sensitivity to treatment, including in ovarian cancer (OvCa). However, current technologies limit mechanical analysis in 3D culture systems. Brillouin Confocal Microscopy is an optical non-contact method to assess the mechanical properties of biological materials. Here, we validate the ability of this technology to assess the mechanical properties of 3D tumor nodules. METHODS: OvCa cells were cultured in 3D using two established methods: (1) overlay cultures on Matrigel; (2) spheroids in ultra-low attachment plates. To alter the mechanical state of these tumors, nodules were immersed in PBS with varying levels of sucrose to induce osmotic stress. Next, nodule mechanical properties were measured by Brillouin microscopy and validated with standard stress-strain tests: Atomic Force Microscopy (AFM) and a parallel plate compression device (Microsquisher). Finally, the nodules were treated with a chemotherapeutic commonly used to manage OvCa, carboplatin, to determine treatment-induced effects on tumor mechanical properties. RESULTS: Brillouin microscopy allows mechanical analysis with limited penetration depth (~ 92 µm for Matrigel method; ~ 54 µm for low attachment method). Brillouin microscopy metrics displayed the same trends as the corresponding "gold-standard" Young's moduli measured with stress-strain methods when the osmolality of the medium was increased. Nodules treated with carboplatin showed a decrease in Brillouin frequency shift. CONCLUSION: This validation study paves the way to evaluate the mechanics of 3D nodules, with micron-scale three-dimensional resolution and without contact, thus extending the experimental possibilities.

10.
Cell Mol Bioeng ; 12(5): 455-480, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31719927

RESUMO

INTRODUCTION: Tumor metastasis to the brain occurs in approximately 20% of all cancer cases and often occurs due to tumor cells crossing the blood-brain barrier (BBB). The brain microenvironment is comprised of a soft hyaluronic acid (HA)-rich extracellular matrix with an elastic modulus of 0.1-1 kPa, whose crosslinking is often altered in disease states. METHODS: To explore the effects of HA crosslinking on breast tumor cell migration, we developed a biomimetic model of the human brain endothelium, consisting of brain microvascular endothelial cell (HBMEC) monolayers on HA and gelatin (HA/gelatin) films with different degrees of crosslinking, as established by varying the concentration of the crosslinker Extralink. RESULTS AND DISCUSSION: Metastatic breast tumor cell migration speed, diffusion coefficient, spreading area, and aspect ratio increased with decreasing HA crosslinking, a mechanosensing trend that correlated with tumor cell actin organization but not CD44 expression. Meanwhile, breast tumor cell incorporation into endothelial monolayers was independent of HA crosslinking density, suggesting that alterations in HA crosslinking density affect tumor cells only after they exit the vasculature. Tumor cells appeared to exploit both the paracellular and transcellular routes of trans-endothelial migration. Quantitative phenotyping of HBMEC junctions via a novel Python software revealed a VEGF-dependent decrease in punctate VE-cadherin junctions and an increase in continuous and perpendicular junctions when HBMECs were treated with tumor cell-secreted factors. CONCLUSIONS: Overall, our quantitative results suggest that a combination of biochemical and physical factors promote tumor cell migration through the BBB.

11.
Ann Biomed Eng ; 47(7): 1675-1687, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30993538

RESUMO

The selective permeability of the blood-brain barrier (BBB) is controlled by tight junction-expressing brain endothelial cells. The integrity of these junctional proteins, which anchor to actin via zonula occludens (e.g., ZO-1), plays a vital role in barrier function. While disrupted junctions are linked with several neurodegenerative diseases, the mechanisms underlying disruption are not fully understood. This is largely due to the lack of appropriate models and efficient techniques to quantify edge-localized protein. Here, we developed a novel junction analyzer program (JAnaP) to semi-automate the quantification of junctional protein presentation. Because significant evidence suggests a link between myosin-II mediated contractility and endothelial barrier properties, we used the JAnaP to investigate how biochemical and physical cues associated with altered contractility influence ZO-1 presentation in brain endothelial cells. Treatment with contractility-decreasing agents increased continuous ZO-1 presentation; however, this increase was greatest on soft gels of brain-relevant stiffness, suggesting improved barrier maturation. This effect was reversed by biochemically inhibiting protein phosphatases to increase cell contractility on soft substrates. These results promote the use of brain-mimetic substrate stiffness in BBB model design and motivates the use of this novel JAnaP to provide insight into the role of junctional protein presentation in BBB physiology and pathologies.


Assuntos
Encéfalo/citologia , Células Endoteliais/fisiologia , Junções Intercelulares/fisiologia , Proteína da Zônula de Oclusão-1/fisiologia , Células Cultivadas , Humanos , Fenótipo
12.
G3 (Bethesda) ; 9(2): 491-503, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30563832

RESUMO

Spinal Muscular Atrophy (SMA) is caused by homozygous mutations in the human survival motor neuron 1 (SMN1) gene. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. SMN is part of an oligomeric complex with core binding partners, collectively called Gemins. Biochemical and cell biological studies demonstrate that certain Gemins are required for proper snRNP assembly and transport. However, the precise functions of most Gemins are unknown. To gain a deeper understanding of the SMN complex in the context of metazoan evolution, we investigated its composition in Drosophila melanogaster Using transgenic flies that exclusively express Flag-tagged SMN from its native promoter, we previously found that Gemin2, Gemin3, Gemin5, and all nine classical Sm proteins, including Lsm10 and Lsm11, co-purify with SMN. Here, we show that CG2941 is also highly enriched in the pulldown. Reciprocal co-immunoprecipitation reveals that epitope-tagged CG2941 interacts with endogenous SMN in Schneider2 cells. Bioinformatic comparisons show that CG2941 shares sequence and structural similarity with metazoan Gemin4. Additional analysis shows that three other genes (CG14164, CG31950 and CG2371) are not orthologous to Gemins 6-7-8, respectively, as previously suggested. In D.melanogaster, CG2941 is located within an evolutionarily recent genomic triplication with two other nearly identical paralogous genes (CG32783 and CG32786). RNAi-mediated knockdown of CG2941 and its two close paralogs reveals that Gemin4 is essential for organismal viability.


Assuntos
Proteínas de Drosophila/genética , Proteínas do Complexo SMN/genética , Animais , Sítios de Ligação , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Evolução Molecular , Ligação Proteica , Proteínas do Complexo SMN/química , Proteínas do Complexo SMN/metabolismo
13.
Mol Biol Cell ; 29(2): 96-110, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29167380

RESUMO

Spinal muscular atrophy (SMA) is caused by homozygous mutations in human SMN1 Expression of a duplicate gene (SMN2) primarily results in skipping of exon 7 and production of an unstable protein isoform, SMNΔ7. Although SMN2 exon skipping is the principal contributor to SMA severity, mechanisms governing stability of survival motor neuron (SMN) isoforms are poorly understood. We used a Drosophila model system and label-free proteomics to identify the SCFSlmb ubiquitin E3 ligase complex as a novel SMN binding partner. SCFSlmb interacts with a phosphor degron embedded within the human and fruitfly SMN YG-box oligomerization domains. Substitution of a conserved serine (S270A) interferes with SCFSlmb binding and stabilizes SMNΔ7. SMA-causing missense mutations that block multimerization of full-length SMN are also stabilized in the degron mutant background. Overexpression of SMNΔ7S270A, but not wild-type (WT) SMNΔ7, provides a protective effect in SMA model mice and human motor neuron cell culture systems. Our findings support a model wherein the degron is exposed when SMN is monomeric and sequestered when SMN forms higher-order multimers.


Assuntos
Proteínas de Drosophila/genética , Atrofia Muscular Espinal/genética , Proteínas de Ligação a RNA/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Animais , Células Cultivadas , Modelos Animais de Doenças , Drosophila , Homozigoto , Humanos , Camundongos , Neurônios Motores/metabolismo , Mutação de Sentido Incorreto , Proteínas do Tecido Nervoso/metabolismo , Polimerização
14.
Bioeng Transl Med ; 2(2): 170-179, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28932818

RESUMO

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have emerged as potential therapeutic agents for numerous applications. EVs offer potential advantages over cell-based therapies with regard to safety, stability and clearance profiles, however production and potency limitations must be addressed to enable eventual translation of EV-based approaches. Thus, we sought to examine the role of specific cell culture parameters on MSC EV production and bioactivity toward informing rational design parameters for scalable EV biomanufacturing. We report significantly reduced MSC EV vascularization bioactivity, as measured by an endothelial cell gap closure assay, with increasing passage in culture by trypsinization, especially beyond passage 4. We further show that increased frequency of EV collection yielded higher numbers of EVs from the same initial number of MSCs over a 24 hr period. Finally, we demonstrate that decreased cell seeding density in culture flasks resulted in increased production of EVs per cell in MSCs and other cell types. Overall, these studies highlight the need for careful consideration of the parameters of cell passage number and cell seeding density in the production of therapeutic EVs at laboratory scale and for rational design of large-scale EV biomanufacturing schemes.

15.
Semin Cell Dev Biol ; 71: 106-117, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28633977

RESUMO

In vivo, cells of the vascular system are subjected to various mechanical stimuli and have demonstrated the ability to adapt their behavior via mechanotransduction. Recent advances in microfluidic and "on-chip" techniques have provided the technology to study these alterations in cell behavior. Contrary to traditional in vitro assays such as transwell plates and parallel plate flow chambers, these microfluidic devices (MFDs) provide the opportunity to integrate multiple mechanical cues (e.g. shear stress, confinement, substrate stiffness, vessel geometry and topography) with in situ quantification capabilities. As such, MFDs can be used to recapitulate the in vivo mechanical setting and systematically vary microenvironmental conditions for improved mechanobiological studies of the endothelium. Additionally, adequate modelling provides for enhanced understanding of disease progression, design of cell separation and drug delivery systems, and the development of biomaterials for tissue engineering applications. Here, we will discuss the advances in knowledge about endothelial cell mechanosensing resulting from the design and application of biomimetic on-chip and microfluidic platforms.


Assuntos
Células Endoteliais , Animais , Biomimética , Cálcio/metabolismo , Células Endoteliais/citologia , Matriz Extracelular/metabolismo , Humanos , Microfluídica , Modelos Biológicos
16.
RNA Biol ; 14(6): 701-711, 2017 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-27648855

RESUMO

Survival Motor Neuron (SMN) protein localizes to both the nucleus and the cytoplasm. Cytoplasmic SMN is diffusely localized in large oligomeric complexes with core member proteins, called Gemins. Biochemical and cell biological studies have demonstrated that the SMN complex is required for the cytoplasmic assembly and nuclear transport of Sm-class ribonucleoproteins (RNPs). Nuclear SMN accumulates with spliceosomal small nuclear (sn)RNPs in Cajal bodies, sub-domains involved in multiple facets of snRNP maturation. Thus, the SMN complex forms stable associations with both nuclear and cytoplasmic snRNPs, and plays a critical role in their biogenesis. In this review, we focus on potential functions of the nuclear SMN complex, with particular emphasis on its role within the Cajal body.


Assuntos
Ribonucleoproteínas Nucleares Pequenas/metabolismo , Proteínas do Complexo SMN/metabolismo , Animais , Núcleo Celular/metabolismo , Corpos Enovelados/metabolismo , Suscetibilidade a Doenças , Humanos , Chaperonas Moleculares/metabolismo , Ligação Proteica , Transporte Proteico , RNA Nuclear Pequeno/genética , RNA Nuclear Pequeno/metabolismo , Spliceossomos/metabolismo , Transcrição Gênica
17.
PLoS Genet ; 10(8): e1004489, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25144193

RESUMO

Mutations in the human survival motor neuron 1 (SMN) gene are the primary cause of spinal muscular atrophy (SMA), a devastating neuromuscular disorder. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. Additional tissue-specific and global functions have been ascribed to SMN; however, their relevance to SMA pathology is poorly understood and controversial. Using Drosophila as a model system, we created an allelic series of twelve Smn missense mutations, originally identified in human SMA patients. We show that animals expressing these SMA-causing mutations display a broad range of phenotypic severities, similar to the human disease. Furthermore, specific interactions with other proteins known to be important for SMN's role in RNP assembly are conserved. Intragenic complementation analyses revealed that the three most severe mutations, all of which map to the YG box self-oligomerization domain of SMN, display a stronger phenotype than the null allele and behave in a dominant fashion. In support of this finding, the severe YG box mutants are defective in self-interaction assays, yet maintain their ability to heterodimerize with wild-type SMN. When expressed at high levels, wild-type SMN is able to suppress the activity of the mutant protein. These results suggest that certain SMN mutants can sequester the wild-type protein into inactive complexes. Molecular modeling of the SMN YG box dimer provides a structural basis for this dominant phenotype. These data demonstrate that important structural and functional features of the SMN YG box are conserved between vertebrates and invertebrates, emphasizing the importance of self-interaction to the proper functioning of SMN.


Assuntos
Proteínas de Drosophila/genética , Drosophila/genética , Atrofia Muscular Espinal/genética , Proteínas de Ligação a RNA/genética , Proteínas do Complexo SMN/genética , Animais , Modelos Animais de Doenças , Proteínas de Drosophila/química , Humanos , Neurônios Motores/patologia , Atrofia Muscular Espinal/patologia , Mutação de Sentido Incorreto/genética , Fenótipo , Multimerização Proteica/genética , Proteínas de Ligação a RNA/química , Ribonucleoproteínas Nucleares Pequenas/genética , Proteínas do Complexo SMN/química , Relação Estrutura-Atividade
18.
Biomacromolecules ; 13(4): 1181-9, 2012 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-22414205

RESUMO

The electrodeposition of hydrogels provides a programmable means to assemble soft matter for various technological applications. We report an anodic method to deposit hydrogel films of the aminopolysaccharide chitosan. Evidence suggests the deposition mechanism involves the electrolysis of chloride to generate reactive chlorine species (e.g., HOCl) that partially oxidize chitosan to generate aldehydes that can couple covalently with amines (presumably through Schiff base linkages). Chitosan's anodic deposition is controllable spatially and temporally. Consistent with a covalent cross-linking mechanism, the deposited chitosan undergoes repeated swelling/deswelling in response to pH changes. Consistent with a covalent conjugation mechanism, proteins could be codeposited and retained within the chitosan film even after detergent washing. As a proof-of-concept, we electroaddressed glucose oxidase to a side-wall electrode of a microfabricated fluidic channel and demonstrated this enzyme could perform electrochemical biosensing functions. Thus, anodic chitosan deposition provides a reagentless, single-step method to electroaddress a stimuli-responsive and biofunctionalized hydrogel film.


Assuntos
Biopolímeros/química , Quitosana/química , Galvanoplastia/métodos , Glucose Oxidase/química , Hidrogéis/química , Técnicas Biossensoriais , Reagentes de Ligações Cruzadas/química , Técnicas Eletroquímicas , Eletrodos , Glucose Oxidase/metabolismo , Concentração de Íons de Hidrogênio
19.
PLoS One ; 4(5): e5669, 2009 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-19479078

RESUMO

BACKGROUND: Leprosy is a chronic infectious disease caused by Mycobacterium leprae that affects almost 250,000 people worldwide. The timing of first infection, geographic origin, and pattern of transmission of the disease are still under investigation. Comparative genomics research has suggested M. leprae evolved either in East Africa or South Asia during the Late Pleistocene before spreading to Europe and the rest of the World. The earliest widely accepted evidence for leprosy is in Asian texts dated to 600 B.C. METHODOLOGY/PRINCIPAL FINDINGS: We report an analysis of pathological conditions in skeletal remains from the second millennium B.C. in India. A middle aged adult male skeleton demonstrates pathological changes in the rhinomaxillary region, degenerative joint disease, infectious involvement of the tibia (periostitis), and injury to the peripheral skeleton. The presence and patterning of lesions was subject to a process of differential diagnosis for leprosy including treponemal disease, leishmaniasis, tuberculosis, osteomyelitis, and non-specific infection. CONCLUSIONS/SIGNIFICANCE: Results indicate that lepromatous leprosy was present in India by 2000 B.C. This evidence represents the oldest documented skeletal evidence for the disease. Our results indicate that Vedic burial traditions in cases of leprosy were present in northwest India prior to the first millennium B.C. Our results also support translations of early Vedic scriptures as the first textual reference to leprosy. The presence of leprosy in skeletal material dated to the post-urban phase of the Indus Age suggests that if M. leprae evolved in Africa, the disease migrated to India before the Late Holocene, possibly during the third millennium B.C. at a time when there was substantial interaction among the Indus Civilization, Mesopotamia, and Egypt. This evidence should be impetus to look for additional skeletal and molecular evidence of leprosy in India and Africa to confirm the African origin of the disease.


Assuntos
Osso e Ossos/patologia , Hanseníase/história , Hanseníase/patologia , Paleopatologia , Arqueologia , História Antiga , Humanos , Índia , Mandíbula/patologia , Crânio/patologia
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