Role of Nitric Oxide Synthase in the Function of the Central Nervous System under Normal and Infectious Conditions

Nitric oxide (NO) was discovered as an endothelium‐derived relaxing factor more than two decades ago. Since then, it has been shown to participate in many pathways. NO has been described as a key mediator of different pathways in the central nervous system (CNS) in both healthy and diseased processes. The three isoforms of nitric oxide synthase differ in their activity patterns and expression in different cells. Neuronal nitric oxide synthase (nNOS) is localized in synaptic spines, astrocytes, and the loose connective tissue surrounding blood vessels in the brain; eNOS is present in both cerebral vascular endothelial cells and motor neurons; and iNOS is induced in astrocytes and microglia under pathological conditions. During physiological processes, NO produced by eNOS/nNOS, respectively, controls blood flow activation, and act as a messenger during long‐term potentiation (LTP). However, under pathological conditions, eNOS appears to be impaired, leading to a reduction in blood flow and, consequently, low oxygen/metabolites delivery, efflux of toxicological agents from the brain tissue and disturbance in the blood‐brain barrier. The NO produced by iNOS in glial cells and nNOS, which triggers the NMDA‐excitotoxic pathway, combines with superoxide anion and results in peroxynitrite synthesis, a potent free radical that contributes to tissue damage in the brain. Here, we intend to show the controversial role of the nitric oxide delivered by the three isoforms of the nitric oxide synthase in the CNS, assess its impact under healthy/pathological conditions and speculate on its possible sequela, particularly in long‐term cognitive decline

P2X7 receptor contributes to long-term neuroinflammation and cognitive impairment in sepsis-surviving mice

Introduction: sepsis is defined as a multifactorial debilitating condition with high risks of death. The intense inflammatory response causes deleterious effects on the brain, a condition called sepsis-associated encephalopathy. Neuroinflammation or pathogen recognition are able to stress cells, resulting in ATP (Adenosine Triphosphate) release and P2X7 receptor activation, which is abundantly expressed in the brain. The P2X7 receptor contributes to chronic neurodegenerative and neuroinflammatory diseases; however, its function in long-term neurological impairment caused by sepsis remains unclear. Therefore, we sought to evaluate the effects of P2X7 receptor activation in neuroinflammatory and behavioral changes in sepsis-surviving mice. Methods: sepsis was induced in wild-type (WT), P2X7−/− , and BBG (Brilliant Blue G)-treated mice by cecal ligation and perforation (CLP). On the thirteenth day after the surgery, the cognitive function of mice was assessed using the novel recognition object and Water T-maze tests. Acetylcholinesterase (AChE) activity, microglial and astrocytic activation markers, and cytokine production were also evaluated. Results: Initially, we observed that both WT and P2X7−/− sepsis-surviving mice showed memory impairment 13 days after surgery, once they did not differentiate between novel and familiar objects. Both groups of animals presented increased AChE activity in the hippocampus and cerebral cortex. However, the absence of P2X7 prevented partly this increase in the cerebral cortex. Likewise, P2X7 absence decreased ionized calcium-binding protein 1 (Iba−1 ) and glial fibrillary acidic protein (GFAP) upregulation in the cerebral cortex of sepsis-surviving animals. There was an increase in GFAP protein levels in the cerebral cortex but not in the hippocampus of both WT and P2X7−/− sepsis-surviving animals. Pharmacological inhibition or genetic deletion of P2X7 receptor attenuated the production of Interleukin-1β (IL-1β), Tumor necrosis factor-α (TNF-α), and Interleukin-10 (IL-10). Conclusion: the modulation of the P2X7 receptor in sepsis-surviving animals may reduce neuroinflammation and prevent cognitive impairment due to sepsisassociated encephalopathy, being considered an important therapeutic target

DJ-1/PARK7 Impairs Bacterial Clearance in Sepsis

Publisher's Version/PDF - grey tick subject to Restrictions below, author can archive publisher's version/PDF General Conditions: On authors' personal website or institutional repository immediatelySubmitted by Sandra Infurna ([email protected]) on 2018-05-24T15:37:12Z No. of bitstreams: 1 tatiana_gutierrz_etal_IOC_2017.pdf: 1664211 bytes, checksum: 7df85b461ce47a093346347362ab896b (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-05-24T15:49:56Z (GMT) No. of bitstreams: 1 tatiana_gutierrz_etal_IOC_2017.pdf: 1664211 bytes, checksum: 7df85b461ce47a093346347362ab896b (MD5)Made available in DSpace on 2018-05-24T15:49:56Z (GMT). No. of bitstreams: 1 tatiana_gutierrz_etal_IOC_2017.pdf: 1664211 bytes, checksum: 7df85b461ce47a093346347362ab896b (MD5) Previous issue date: 2017Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunofarmacologia. Rio de Janeiro, RJ. Brasil.Múltipla autoria - ver em NotasEffective and rapid bacterial clearance is a fundamental determinant of outcomes in sepsis. DJ-1 is a well-established reactive oxygen species (ROS) scavenger

Infectious disease-associated encephalopathies

Infectious diseases may affect brain function and cause encephalopathy even when the pathogen does not directly infect the central nervous system, known as infectious disease-associated encephalopathy. The systemic inflammatory process may result in neuroinflammation, with glial cell activation and increased levels of cytokines, reduced neurotrophic factors, blood-brain barrier dysfunction, neurotransmitter metabolism imbalances, and neurotoxicity, and behavioral and cognitive impairments often occur in the late course. Even though infectious disease-associated encephalopathies may cause devastating neurologic and cognitive deficits, the concept of infectious disease-associated encephalopathies is still under-investigated; knowledge of the underlying mechanisms, which may be distinct from those of encephalopathies of non-infectious cause, is still limited. In this review, we focus on the pathophysiology of encephalopathies associated with peripheral (sepsis, malaria, influenza, and COVID-19), emerging therapeutic strategies, and the role of neuroinflammation

Scientific venturing for early-stage professionals (ESPs), a key concept in the innovation ecosystem

Early-stage professionals (ESPs) and senior scientists who want to transition from academia to the industry need support to develop new skills and know-how to endeavor this challenge. However, this topic is significantly underserved in the field of cell and gene therapy, slowing down ESPs' potential to make this step. The authors of this article, members of the ESPs in the South and Central America Subcommittee at the International Society for Cell and Gene Therapy, propose the concept of "scientific venturing," which stands for the process by which scientists become entrepreneurs or part of a company. In our article, we provide key aspects to understand this concept, considering key personality traits that need to be developed and a discussion about the "innovation ecosystem." Later, we consider how scientific venturing may result in an increase in difficulty in nascent innovation ecosystems such as Latin America, in comparison with those more advanced and mature in high-income countries. Finally, we provide key information for the ESPs and other professionals about the stages of private and public investment, including information about the resources needed for the sustainability of companies and startups. Understanding what scientific venturing involves for ESPs is key to taking advantage of the maturity of an innovation ecosystem, its network, and available opportunities

Stem cells and respiratory diseases

Stem cells have a multitude of clinical implications in the lung. This article is a critical review that includes clinical and experimental studies of MedLine and SciElo database in the last 10 years, where we highlight the effects of stem cell therapy in acute respiratory distress syndrome or more chronic disorders such as lung fibrosis and emphysema. Although, many studies have shown the beneficial effects of stem cells in lung development, repair and remodeling; some important questions need to be answered to better understand the mechanisms that control cell division and differentiation, therefore enabling the use of cell therapy in human respiratory diseases.<br>As células-tronco têm uma infinidade de implicações clínicas no pulmão. Este artigo é uma revisão crítica que inclui estudos clínicos e experimentais advindos do banco de dados do MEDLINE e SciElo nos últimos 10 anos, onde foram destacados os efeitos da terapia celular na síndrome do desconforto respiratório agudo ou doenças mais crônicas, como fibrose pulmonar e enfisema. Apesar de muitos estudos demonstrarem os efeitos benéficos das células-tronco no desenvolvimento, reparo e remodelamento pulmonar; algumas questões ainda precisam ser respondidas para um melhor entendimento dos mecanismos que controlam a divisão celular e diferenciação, permitindo o uso da terapia celular nas doenças respiratórias

Bone Marrow-Derived Mononuclear Cell Therapy in Papain-Induced Experimental Pulmonary Emphysema

Murine papain-induced emphysema is a model that reproduces many of the features found in patients. Bone marrow-derived mononuclear cells (BMMC) have already been used to repair the alveolar epithelium in respiratory diseases, but not in the papain model. Thus, we hypothesized that BMMC could prevent the pathophysiological processes in papain-induced experimental emphysema. Female BALB/c mice received intratracheal instillation of 50 μL of saline (S groups) or papain (P groups, 10 IU/50 μl of saline) on days 1 and 7 of the experimental protocol. On the 14th day, 2 × 106 BMMC of male BALB/c mice (SC21 and PC21) or saline (SS21 and PS21) were injected by the jugular vein. Analyses were done on days 14 (S14 and P14) and 21 (SS21, PS21, SC21, and PC21) of the protocol. qPCR evaluated the presence of the Y chromosome in the lungs of BMMC recipient animals. Functional residual capacity (FRC), alveolar diameter, cellularity, elastic fiber content, concentrations of TNF-α, IL-1β, IL-6, MIP-2, KC, IFN-γ, apoptosis, mRNA expression of the dual oxidase (DUOX1 and DUOX2), production of H2O2 and DUOX activity were evaluated in lung tissue. We did not detect the Y chromosome in recipients' lungs. FRC, alveolar diameter, polymorphonuclear cells (PMN) and levels of KC, MIP-2, and IFN-γ increased in P14 and PS21 groups; the changes in the latter were reverted by BMMC. TNF-α, IL-1β e IL-6 were similar in all groups. The amount of elastic fibers was smaller in P14 and PS21 than in other groups, and BMMC did not increase it in PC21 mice. PS21 animals showed increased DUOX activity and mRNA expression for DUOX1 and 2. Cell therapy reverted the activity of DUOX and mRNA expression of DUOX1. BMMC reduced mRNA expression of DUOX2. Apoptosis index was elevated in PS21 mice, which was reduced by cell therapy in PC21. Static compliance, viscoelastic component of elastance and pressure to overcome viscoelasticity were increased in P14 and PS21 groups. These changes and the high resistive pressure found on day 21 were reverted by BMMC. In conclusion, BMMC showed potent anti-inflammatory, antiapoptotic, antioxidant, and restorative roles in papain-triggered pulmonary emphysema