GlyT1 Inhibition by NFPS Promotes Neuroprotection in Amyloid-ß-Induced Alzheimer's Disease Animal Model.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-ß, leading to N-methyl-D-aspartate (NMDA) receptor-dependent synaptic depression, spine elimination, and memory deficits. Glycine transporter type 1 (GlyT1) modulates glutamatergic neurotransmission via NMDA receptors (NMDAR), presenting a potential alternative therapeutic approach for AD. This study investigates the neuroprotective potential of GlyT1 inhibition in an amyloid-ß-induced AD mouse model. C57BL/6 mice were treated with N-[3-([1,1-Biphenyl]-4-yloxy)-3-(4-fluorophenyl)propyl]-N-methylglycine (NFPS), a GlyT1 inhibitor, 24 h prior to intrahippocampal injection of amyloid-ß. NFPS pretreatment prevented amyloid-ß-induced cognitive deficits in short-term and long-term memory, evidenced by novel object recognition and spatial memory tasks. Moreover, NFPS pretreatment curbed microglial activation, astrocytic reactivity, and subsequent neuronal damage from amyloid-ß injection. An extensive label-free quantitative UPLC-MSE proteomic analysis was performed on the hippocampi of mice treated with NFPS. In proteomics, KEGG enrichment analysis revealed increased in dopaminergic synapse, purine-containing compound biosynthetic process and long-term potentiation, and a reduction in Glucose catabolic process and glycolytic process pathways. The western blot analysis confirmed that NFPS treatment elevated BDNF levels, correlating with enhanced TRKB phosphorylation and mTOR activation. Moreover, NFPS treatment reduced the GluN2B expression after 6 h, which was associated with an increase on CaMKIV and CREB phosphorylation. Collectively, these findings demonstrate that GlyT1 inhibition by NFPS activates diverse neuroprotective pathways, enhancing long-term potentiation signaling and countering amyloid-ß-induced hippocampal damage.

L-proline transporter inhibitor (LQFM215) promotes neuroprotection in ischemic stroke.

BACKGROUND: L-proline transporter (PROT/SLC6A7) is closely associated with glutamatergic neurotransmission, where L-proline modulates the NMDA receptor (NMDAR) function. NMDAR-mediated excitotoxicity is a primary cause of neuronal death following stroke, which is triggered by the uncontrolled release of glutamate during the ischemic process. After ischemic stroke, L-proline levels show a reduction in the plasma, but high circulating levels of this molecule indicate good functional recovery. This work aimed to produce new PROT inhibitors and explore their effects on ischemic stroke. METHODS: Initially, we built a three-dimensional model of the PROT protein and run a molecular docking with the newly designed compounds (LQFM215, LQFM216, and LQFM217). Then, we synthesized new PROT inhibitors by molecular hybridization, and proline uptake was measured in ex vivo and in vivo models. The behavioral characterization of the treated mice was performed by the open-field test, elevated plus-maze, Y-maze, and forced swimming test. We used the permanent middle cerebral artery occlusion (MCAO) model to study the ischemic stroke damage and analyzed the motor impairment with limb clasping or cylinder tests. RESULTS: LQFM215 inhibited proline uptake in hippocampal synaptosomes, and the LQFM215 treatment reduced proline levels in the mouse hippocampus. LQFM215 reduced the locomotor and exploratory activity in mice and did not show any anxiety-related or working memory impairments. In the MCAO model, LQFM215 pre-treatment and treatment reduced the infarcted area and reduced motor impairments in the cylinder test and limb clasping. CONCLUSIONS: This dataset suggests that the new compounds inhibit cerebral L-proline uptake and that LQFM215 promotes neuroprotection and neuro-repair in the acute ischemic stroke model.

Biomarkers in Hypertension and Hypertension-related Disorders.

Systemic arterial hypertension (SAH) is a major risk factor for several secondary diseases, especially cardiovascular and renal conditions. SAH has a high prevalence worldwide, and its precise and early recognition is important to prevent the development of secondary outcomes. In this field, the study of biomarkers represents an important approach to diagnosing and predicting the disease and its associated conditions. The use of biomarkers in hypertension and hypertension-related disorders, such as ischemic stroke, intracerebral hemorrhage, transient ischemic attack, acute myocardial infarction, angina pectoris and chronic kidney disease, are discussed in this review. Establishing a potential pool of biomarkers may contribute to a non-invasive and improved approach for their diagnosis, prognosis, risk assessment, therapy management and pharmacological responses to a therapeutic intervention to improve patients' quality of life and prevent unfavorable outcomes.

Organoids as a novel tool in modelling infectious diseases.

Infectious diseases worldwide affect human health and have important societal impacts. A better understanding of infectious diseases is urgently needed. In vitro and in vivo infection models have brought notable contributions to the current knowledge of these diseases. Organoids are multicellular culture systems resembling tissue architecture and function, recapitulating many characteristics of human disease and elucidating mechanisms of host-infectious agent interactions in the respiratory and gastrointestinal systems, the central nervous system and the skin. Here, we discuss the applicability of the organoid technology for modeling pathogenesis, host response and features, which can be explored for the development of preventive and therapeutic treatments.

Organoides de cérebro como modelos de doenças de Alzheimer e Parkinson: uma revisão narrativa sobre as perspectivas para medicina regenerativa e personalizada / Brain organoids as models of Alzheimer's and Parkinson's diseases: a narrative review on perspectives for regenerative and personalized medicine

Há muitos anos a cultura celular bidimensional (2D) é utilizada como modelo de estudo de doenças, possuindo grande importância na medicina regenerativa, apesar de ainda conter limitações significativas. A fim de contornar essas limitações, a cultura celular tridimensional (3D) propõe uma organização mais complexa e sustentável que pode ser produzida a partir de células-tronco adultas (ASCs), células-tronco embrionárias (ESCs) ou células-tronco pluripotentes induzidas (iPSCs). A cultura 3D possibilitou o cultivo de células em um ambiente mais próximo do fisiológico, levando à formação de distintos tecidos órgãos-específicos. Em outras palavras, a cultura de células 3D possibilita a criação de estruturas orgânicas muito semelhantes aos órgãos de um ser humano, tanto estruturalmente, quanto funcionalmente. Desse modo, tem-se o que é chamado de organoides. O uso dos organoides tem crescido exponencialmente em ambientes in vitro, permitindo a análise e observação dos diversos fenômenos fisiológicos existentes. Como exemplo, pode-se citar os organoides cerebrais ("mini-brains") reproduzidos in vitro buscando delinear as peculiaridades e complexidades do cérebro humano, com o objetivo de compreender algumas disfunções neurológicas que acometem esse sistema, como as duas principais doenças neurodegenerativas: Doenças de Alzheimer e Parkinson. Portanto, os organoides cerebrais podem permitir notável avanço da medicina regenerativa aplicada a doenças neurodegenerativas, já que esses "mini-brains" podem ser produzidos a partir de células do próprio paciente. Isso permitirá intervenções personalizadas, como testagens farmacológicas, a fim de definir qual seria o melhor tratamento medicamentoso. Consequentemente, essa tecnologia pode permitir terapias mais eficientes e individualizadas - o que é fundamental para a Medicina Personalizada (AU).

For many years, two-dimensional (2D) cell culture has been used as a model to study diseases, having great importance in regenerative medicine, despite still having significant limitations. In order to circumvent these limitations, three-dimensional (3D) cell culture proposes a more complex and sustainable organization that can be produced from adult stem cells (ASCs), embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs). The 3D culture enabled the cultivation of cells in an environment closer to the physiological one, leading to the formation of different organ-specific tissues. In other words, 3D cell culture makes it possible to create organic structures very similar to the organs of a human being, both structurally and functionally. In this way, we have what are called organoids. The use of organoids has grown exponentially in in vitro environments, allowing the analysis and observation of the various existing physiological phenomena. As an example, we can mention the brain organoids ("mini-brains") reproduced in vitro, seeking to delineate the peculiarities and complexities of the human brain, in order to understand some neurological dysfunctions that affect this system, such as the two main neurodegenerative diseases: Alzheimer's and Parkinson's Diseases. Therefore, brain organoids may allow a remarkable advance in regenerative medicine applied to neurodegenerative diseases, as these "mini-brains" can be produced from the patient's own cells. This will allow for personalized interventions, such as drug testing, in order to define what would be the best drug treatment. Consequently, this technology can enable more efficient and individualized therapies - which is fundamental for Personalized Medicine (AU).

The Role of Astrocytes in the Neurorepair Process.

Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.

Neurobiology of glycine transporters: From molecules to behavior.

Glycine transporters (GlyTs) are Na+/Cl--dependent neurotransmitter transporters, responsible for l-glycine uptake into the central nervous system. GlyTs are members of the solute carrier family 6 (SLC6) and comprise glycine transporter type 1 (SLC6A9; GlyT1) and glycine transporter type 2 (SLC6A5; Glyt2). GlyT1 and GlyT2 are expressed on both astrocytes and neurons, but their expression pattern in brain tissue is foremost related to neurotransmission. GlyT2 is markedly expressed in brainstem, spinal cord and cerebellum, where it is responsible for glycine uptake into glycinergic and GABAergic terminals. GlyT1 is abundant in neocortex, thalamus and hippocampus, where it is expressed in astrocytes, and involved in glutamatergic neurotransmission. Consequently, inhibition of GlyT1 transporters can modulate glutamatergic neurotransmission through NMDA receptors, suggesting an alternative therapeutic strategy. In this review, we focus on recent progress in the understanding of GlyTs role in brain function and in various diseases, such as epilepsy, hyperekplexia, neuropathic pain, drug addiction, schizophrenia and stroke, as well as in neurodegenerative disorders.