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1.
PLoS Genet ; 20(8): e1011156, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39137212

RESUMO

Phosphorus is essential in all cells' structural, metabolic and regulatory functions. For fungal cells that import inorganic phosphate (Pi) up a steep concentration gradient, surface Pi transporters are critical capacitators of growth. Fungi must deploy Pi transporters that enable optimal Pi uptake in pH and Pi concentration ranges prevalent in their environments. Single, triple and quadruple mutants were used to characterize the four Pi transporters we identified for the human fungal pathogen Candida albicans, which must adapt to alkaline conditions during invasion of the host bloodstream and deep organs. A high-affinity Pi transporter, Pho84, was most efficient across the widest pH range while another, Pho89, showed high-affinity characteristics only within one pH unit of neutral. Two low-affinity Pi transporters, Pho87 and Fgr2, were active only in acidic conditions. Only Pho84 among the Pi transporters was clearly required in previously identified Pi-related functions including Target of Rapamycin Complex 1 signaling, oxidative stress resistance and hyphal growth. We used in vitro evolution and whole genome sequencing as an unbiased forward genetic approach to probe adaptation to prolonged Pi scarcity of two quadruple mutant lineages lacking all 4 Pi transporters. Lineage-specific genomic changes corresponded to divergent success of the two lineages in fitness recovery during Pi limitation. Initial, large-scale genomic alterations like aneuploidies and loss of heterozygosity eventually resolved, as populations gained small-scale mutations. Severity of some phenotypes linked to Pi starvation, like cell wall stress hypersensitivity, decreased in parallel to evolving populations' fitness recovery in Pi scarcity, while severity of others like membrane stress responses diverged from Pi scarcity fitness. Among preliminary candidate genes for contributors to fitness recovery, those with links to TORC1 were overrepresented. Since Pi homeostasis differs substantially between fungi and humans, adaptive processes to Pi deprivation may harbor small-molecule targets that impact fungal growth, stress resistance and virulence.


Assuntos
Adaptação Fisiológica , Candida albicans , Proteínas Fúngicas , Fosfatos , Fosfatos/metabolismo , Candida albicans/genética , Candida albicans/metabolismo , Adaptação Fisiológica/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Mutação , Regulação Fúngica da Expressão Gênica , Humanos , Transporte Biológico/genética
2.
J Neurosci ; 43(14): 2497-2514, 2023 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-36849417

RESUMO

An important step in neural information processing is the transformation of membrane voltage into calcium signals leading to transmitter release. However, the effect of voltage to calcium transformation on neural responses to different sensory stimuli is not well understood. Here, we use in vivo two-photon imaging of genetically encoded voltage and calcium indicators, ArcLight and GCaMP6f, respectively, to measure responses in direction-selective T4 neurons of female Drosophila Comparison between ArcLight and GCaMP6f signals reveals calcium signals to have a significantly higher direction selectivity compared with voltage signals. Using these recordings, we build a model which transforms T4 voltage responses into calcium responses. Using a cascade of thresholding, temporal filtering and a stationary nonlinearity, the model reproduces experimentally measured calcium responses across different visual stimuli. These findings provide a mechanistic underpinning of the voltage to calcium transformation and show how this processing step, in addition to synaptic mechanisms on the dendrites of T4 cells, enhances direction selectivity in the output signal of T4 neurons. Measuring the directional tuning of postsynaptic vertical system (VS)-cells with inputs from other cells blocked, we found that, indeed, it matches the one of the calcium signal in presynaptic T4 cells.SIGNIFICANCE STATEMENT The transformation of voltage to calcium influx is an important step in the signaling cascade within a nerve cell. While this process has been intensely studied in the context of transmitter release mechanism, its consequences for information transmission and neural computation are unclear. Here, we measured both membrane voltage and cytosolic calcium levels in direction-selective cells of Drosophila in response to a large set of visual stimuli. We found direction selectivity in the calcium signal to be significantly enhanced compared with membrane voltage through a nonlinear transformation of voltage to calcium. Our findings highlight the importance of an additional step in the signaling cascade for information processing within single nerve cells.


Assuntos
Cálcio , Drosophila , Animais , Feminino , Cálcio/metabolismo , Drosophila/fisiologia , Neurônios/fisiologia , Transdução de Sinais , Retroalimentação Fisiológica , Estimulação Luminosa/métodos
3.
Org Biomol Chem ; 22(27): 5653-5664, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38919997

RESUMO

Brønsted acid catalyzed regioselective ring opening of aziridines by phenols and thiophenols have been reported. Involvement of a series of aziridines with a range of phenols and thiophenols offer the generality of the reported protocol. Completion of the reaction at room temperature within very short time brings the uniqueness of the developed technique. To emphasis on the application of the developed methodology, the products have been used for the further synthesis of a range of useful and novel heterocyclic molecules such as indolines, indoles, benzothiazines, dihydrobenzothiazines, benzo-oxazines and benzochromenes.

4.
Kidney Blood Press Res ; 49(1): 69-80, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38185105

RESUMO

INTRODUCTION: Renal fibrosis is a critical event in the development and progression of chronic kidney disease (CKD), and it is considered the final common pathway for all types of CKD. The prevalence of CKD is higher in females; however, males have a greater prevalence of end-stage renal disease. In addition, low birth weight and low nephron number are associated with increased risk for CKD. This study examined the development and severity of unilateral ureter obstruction (UUO)-induced renal fibrosis in male and female wild-type (ROP +/+) and mutant (ROP Os/+) mice, a mouse model of low nephron number. METHODS: Male and female ROP +/+ and ROP Os/+ mice were subjected to UUO, and kidney tissue was collected at the end of the 10-day experimental period. Kidney histological analysis and mRNA expression determined renal fibrosis, tubular injury, collagen deposition, extracellular matrix proteins, and immune cell infiltration. RESULTS: Male and female UUO mice demonstrated marked renal injury, kidney fibrosis, and renal extracellular matrix production. Renal fibrosis and α-smooth muscle actin were increased to a similar degree in ROP +/+ and ROP Os/+ mice with UUO of either sex. There were also no sex differences in renal tubular cast formation or renal infiltration of macrophage in ROP +/+ and ROP Os/+ UUO mice. Interestingly, renal fibrosis and α-smooth muscle actin were 1.5-3-fold greater in UUO-ROP +/+ compared to UUO-ROP Os/+ mice. Renal inflammation phenotypes following UUO were also 30-45% greater in ROP +/+ compared to ROP Os/+ mice. Likewise, expression of extracellular matrix and renal fibrotic genes was greater in UUO-ROP +/+ mice compared to UUO-ROP Os/+ mice. In contrast to these findings, ROP Os/+ mice with UUO demonstrated glomerular hypertrophy with 50% greater glomerular tuft area compared to ROP +/+ with UUO. Glomerular hypertrophy was not sex-dependent in any of the genotypes of ROP mice. These findings provide evidence that low nephron number contributes to UUO-induced glomerular hypertrophy in ROP Os/+ mice but does not enhance renal fibrosis, inflammation, and renal tubular injury. CONCLUSION: Taken together, we demonstrate that low nephron number contributes to enhanced glomerular hypertrophy but not kidney fibrosis and tubular injury. We also demonstrate that none of the changes caused by UUO was affected by sex in any of the ROP mice genotypes.


Assuntos
Insuficiência Renal Crônica , Obstrução Ureteral , Feminino , Masculino , Animais , Camundongos , Obstrução Ureteral/complicações , Obstrução Ureteral/metabolismo , Actinas/metabolismo , Caracteres Sexuais , Rim/patologia , Insuficiência Renal Crônica/complicações , Inflamação/patologia , Fibrose , Hipertrofia/patologia , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
5.
PLoS Genet ; 17(7): e1009460, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34314427

RESUMO

Visual perception of the environment is mediated by specialized photoreceptor (PR) neurons of the eye. Each PR expresses photosensitive opsins, which are activated by a particular wavelength of light. In most insects, the visual system comprises a pair of compound eyes that are mainly associated with motion, color or polarized light detection, and a triplet of ocelli that are thought to be critical during flight to detect horizon and movements. It is widely believed that the evolutionary diversification of compound eye and ocelli in insects occurred from an ancestral visual organ around 500 million years ago. Concurrently, opsin genes were also duplicated to provide distinct spectral sensitivities to different PRs of compound eye and ocelli. In the fruit fly Drosophila melanogaster, Rhodopsin1 (Rh1) and Rh2 are closely related opsins that originated from the duplication of a single ancestral gene. However, in the visual organs, Rh2 is uniquely expressed in ocelli whereas Rh1 is uniquely expressed in outer PRs of the compound eye. It is currently unknown how this differential expression of Rh1 and Rh2 in the two visual organs is controlled to provide unique spectral sensitivities to ocelli and compound eyes. Here, we show that Homothorax (Hth) is expressed in ocelli and confers proper rhodopsin expression. We find that Hth controls a binary Rhodopsin switch in ocelli to promote Rh2 expression and repress Rh1 expression. Genetic and molecular analysis of rh1 and rh2 supports that Hth acts through their promoters to regulate Rhodopsin expression in the ocelli. Finally, we also show that when ectopically expressed in the retina, hth is sufficient to induce Rh2 expression only at the outer PRs in a cell autonomous manner. We therefore propose that the diversification of rhodpsins in the ocelli and retinal outer PRs occurred by duplication of an ancestral gene, which is under the control of Homothorax.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Proteínas de Homeodomínio/genética , Fenômenos Fisiológicos Oculares/genética , Rodopsina/genética , Animais , Animais Geneticamente Modificados , Drosophila melanogaster/genética , Regulação da Expressão Gênica , Proteínas de Membrana/genética , Células Fotorreceptoras/metabolismo , Regiões Promotoras Genéticas , Retina/fisiologia
6.
J Microencapsul ; 41(5): 327-344, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38829223

RESUMO

AIM: The work reports a novel nanophytosomal gel encapsulating Alpinia galanga (L.) Willd leaf essential oil to treat periodontal infections. METHODS: Alpinia oil-loaded nanophytosomes (ANPs) were formulated by lipid layer hydration technique and were evaluated by FESEM, cryo-TEM, loading efficiency, zeta potential, particle size, release profile etc. Selected ANPs-loaded gel (ANPsG) was evaluated by both in vitro and in vivo methods. RESULTS: Selected ANPs were spherical, unilamellar, 49.32 ± 2.1 nm size, 0.45 PDI, -46.7 ± 0.8 mV zeta potential, 9.8 ± 0.5% (w/w) loading, 86.4 ± 3.02% (w/w) loading efficiency with sustained release profile. ANPsG showed good spreadability (6.8 ± 0.3 gm.cm/sec), extrudability (79.33 ± 1.5%), viscosity (36522 ± 0.82 cps), mucoadhesive strength (44.56 ± 3.5 gf) with sustained ex vivo release tendency. Satisfied ZOI and MIC was observed for ANPsG against periodontal bacteria vs. standard/control. ANPsG efficiently treated infection in ligature induced periodontitis model. Key pharmacokinetic parameters like AUC, MRT, Vd were enhanced for ANPsG. CONCLUSION: ANPsG may be investigated for futuristic clinical studies.


Assuntos
Alpinia , Géis , Óleos Voláteis , Folhas de Planta , Óleos Voláteis/química , Óleos Voláteis/administração & dosagem , Óleos Voláteis/farmacocinética , Óleos Voláteis/farmacologia , Alpinia/química , Animais , Géis/química , Folhas de Planta/química , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/administração & dosagem , Doenças Periodontais/tratamento farmacológico , Masculino , Nanopartículas/química , Ratos , Periodontite/tratamento farmacológico , Simulação por Computador
7.
J Biol Chem ; 298(10): 102418, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36030823

RESUMO

Macrophages (MФ) are an essential immune cell for defense and repair that travel to different tissues and adapt based on local stimuli. A critical factor that may govern their polarization is the crosstalk between metabolism and epigenetics. However, simultaneous measurements of metabolites, epigenetics, and proteins (phenotype) have been a major technical challenge. To address this, we have developed a novel triomics approach using mass spectrometry to comprehensively analyze metabolites, proteins, and histone modifications in a single sample. To demonstrate this technique, we investigated the metabolic-epigenetic-phenotype axis following polarization of human blood-derived monocytes into either 'proinflammatory M1-' or 'anti-inflammatory M2-' MФs. We report here a complex relationship between arginine, tryptophan, glucose, and the citric acid cycle metabolism, protein and histone post-translational modifications, and human macrophage polarization that was previously not described. Surprisingly, M1-MФs had globally reduced histone acetylation levels but high levels of acetylated amino acids. This suggests acetyl-CoA was diverted, in part, toward acetylated amino acids. Consistent with this, stable isotope tracing of glucose revealed reduced usage of acetyl-CoA for histone acetylation in M1-MФs. Furthermore, isotope tracing also revealed MФs uncoupled glycolysis from the tricarboxylic acid cycle, as evidenced by poor isotope enrichment of succinate. M2-MФs had high levels of kynurenine and serotonin, which are reported to have immune-suppressive effects. Kynurenine is upstream of de novo NAD+ metabolism that is a necessary cofactor for Sirtuin-type histone deacetylases. Taken together, we demonstrate a complex interplay between metabolism and epigenetics that may ultimately influence cell phenotype.


Assuntos
Polaridade Celular , Cinurenina , Macrófagos , Humanos , Acetilcoenzima A/metabolismo , Epigênese Genética , Glucose/metabolismo , Histonas/genética , Histonas/metabolismo , Cinurenina/metabolismo , Macrófagos/metabolismo , Polaridade Celular/genética
8.
J Biol Chem ; 298(3): 101716, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35151687

RESUMO

The CHKB gene encodes choline kinase ß, which catalyzes the first step in the biosynthetic pathway for the major phospholipid phosphatidylcholine. Homozygous loss-of-function variants in human CHKB are associated with a congenital muscular dystrophy. Dilated cardiomyopathy is present in some CHKB patients and can cause heart failure and death. Mechanisms underlying a cardiac phenotype due to decreased CHKB levels are not well characterized. We determined that there is cardiac hypertrophy in Chkb-/- mice along with a decrease in left ventricle size, internal diameter, and stroke volume compared with wildtype and Chkb+/- mice. Unlike wildtype mice, 60% of the Chkb+/- and all Chkb-/- mice tested displayed arrhythmic events when challenged with isoproterenol. Lipidomic analysis revealed that the major change in lipid level in Chkb+/- and Chkb-/- hearts was an increase in the arrhythmogenic lipid acylcarnitine. An increase in acylcarnitine level is also associated with a defect in the ability of mitochondria to use fatty acids for energy and we observed that mitochondria from Chkb-/- hearts had abnormal cristae and inefficient electron transport chain activity. Atrial natriuretic peptide (ANP) is a hormone produced by the heart that protects against the development of heart failure including ventricular conduction defects. We determined that there was a decrease in expression of ANP, its receptor NPRA, as well as ventricular conduction system markers in Chkb+/- and Chkb-/- mice.


Assuntos
Arritmias Cardíacas , Colina Quinase , Insuficiência Cardíaca , Animais , Arritmias Cardíacas/enzimologia , Arritmias Cardíacas/genética , Fator Natriurético Atrial/genética , Colina Quinase/deficiência , Colina Quinase/genética , Colina Quinase/metabolismo , Modelos Animais de Doenças , Insuficiência Cardíaca/enzimologia , Insuficiência Cardíaca/genética , Humanos , Camundongos , Fosfatidilcolinas/metabolismo
9.
J Org Chem ; 88(22): 15580-15588, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-37933871

RESUMO

Benzofuran and naphthofuran derivatives are synthesized from readily available phenols and naphthols. Regioselective ring openings of 2H-azirine followed by in situ aromatization using a catalytic amount of Brønsted acid have established the novelty of the methodology. The involvement of a series of 2H-azirines with a variety of phenols, 1-naphthols, and 2-naphthols showed the generality of the protocol. In-depth density functional theory calculations revealed the reaction mechanism with the energies of the intermediates and transition states of a model reaction. An alternate pathway of the mechanism has also been proposed with computer modeling.

10.
Org Biomol Chem ; 21(4): 838-845, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36602157

RESUMO

An efficient dual Pd-catalytic system was developed for one-pot synthesis of 3-sulfenylindoles via C-C, C-N and C-S bond construction directly from unactivated 2-iodo(NH)anilines under mild reaction conditions. Furthermore, 3-selenyl/halo/carbon-functionalized indoles were synthesized in good yields and a short reaction time. The synthetic utility of 3-sulfenylindole was also demonstrated. The key role of solvent in palladium catalysis was unravelled by DFT.

11.
Bioprocess Biosyst Eng ; 46(6): 789-802, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36971837

RESUMO

Fluorescence spectroscopy is a non-invasive and highly sensitive method for bioprocess monitoring. The use of fluorescence spectroscopy is not very well established in the industry for in-line monitoring. In the present work, a 2-D fluorometer with two excitation lights (365 and 405 nm) and emission spectra in the range of 350-850 nm were used for in-line monitoring of two strains of Bordetella pertussis cultivation operated in batch and fed batch. A Partial Least Squares (PLS) based regression model was used for the estimation of cell biomass, amino acids (glutamate and proline) and antigen (Pertactin) produced. It was observed that accurate predictions were achieved when models were calibrated separately for each cell strain and nutrient media formulation. Also, prediction accuracy was improved when dissolved oxygen, agitation and culture volume are added as additional features in the regression model. The proposed approach of combining in-line fluorescence and other online measurements is shown to have good potential for in-line monitoring of bioprocesses.


Assuntos
Aminoácidos , Bordetella pertussis , Espectrometria de Fluorescência/métodos , Análise dos Mínimos Quadrados , Biomassa
12.
J Cell Physiol ; 237(7): 2888-2912, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35476800

RESUMO

After ejaculation, sperm show a limited capacity for transcription and translation. In the oviduct, most of the signalling in sperm is nongenomic and is mediated through membrane receptors. Studies have shown that the cation channel of sperm (CatSper), cAMP, cGMP, protein kinases, and tyrosine phosphorylation are involved in the nongenomic signalling of progesterone (P4) in sperm. However, it is not known whether there is an interplay between P4 and cannabinoid receptors 1 and 2 (CB1 and CB2), transient receptor potential vanilloid 1 (TRPV1), CatSper channels, cAMP, inositol trisphosphate receptor (IP3R), and mitogen-activated protein kinase (MAPK); these potential regulators are involved in the regulation of capacitation and the acrosome reaction. In the present study, selective blockers of CB1, CB2, TRPV1, CatSper channels, cAMP, protein kinase A (PKA), IP3R, and MAPK were used to identify their involvement in P4-mediated bull sperm capacitation and the acrosome reaction. Selective blocking of any one of the molecules caused a significant reduction in P4 signalling (p < 0.05). Interestingly, blocking these molecules in combination followed by treatment with P4 resulted in the complete absence of capacitation and the acrosome reaction. Blocking a single receptor was not able to eliminate the P4-induced capacitation and the acrosome reaction. In addition to the CB1 and CB2 receptors, there may be other signalling pathways that mediate P4 signalling. In conclusion, P4 signalling exhibited interplay with the cannabinoid receptors. The regulation of sperm capacitation and the acrosome reaction also involved cAMP, PKA, l-type and T-type calcium channels, TRPV1, inositol trisphosphate, and MAPK.


Assuntos
Reação Acrossômica , Bovinos/fisiologia , Capacitação Espermática , Animais , Masculino , Receptores de Canabinoides/metabolismo , Receptores de Progesterona/metabolismo , Motilidade dos Espermatozoides , Espermatozoides/metabolismo
13.
Eur J Neurosci ; 56(1): 3553-3569, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35481869

RESUMO

Although it is well recognized that the circadian timing system profoundly influences cognitive performance, the underlying molecular mechanisms remain poorly defined. Our previous work has found that the mitogen-activated protein kinase-interacting kinase (MNK)-eukaryotic translation initiation factor 4E (eIF4E) axis, a conserved cellular signalling pathway regulating mRNA translation, modulates the function of the suprachiasmatic nucleus (SCN), the master circadian clock. Here, with the use of a combination of genetic, biochemical and behavioural approaches, we investigated the distribution and temporal regulation of eIF4E phosphorylation in the brain and its role in regulating the diurnal oscillations of some aspects of cognition in mice. We found that activities of the MNK-eIF4E axis, as indicated by the level of eIF4E phosphorylation at Ser209, exhibited significant circadian oscillations in a variety of brain regions, including but not limited to the prefrontal cortex, the hippocampus, the amygdala and the cerebellum. Phosphorylated eIF4E was enriched in neurons but not in astrocytes or microglia. Mice lacking eIF4E phosphorylation (eIF4ES209A/S209A ) or the MNKs (Mnk1-/-,2-/- ), the kinases that phosphorylate eIF4E, exhibited impaired diurnal variations of novel object recognition, object location memory, Barnes maze learning and ambulatory activities. Together, these results suggest that circadian activities of the MNK-eIF4E axis contribute to the diurnal rhythms of some cognitive functions, highlighting a role for rhythmic translational control in circadian regulation of cognitive performance.


Assuntos
Ritmo Circadiano , Fator de Iniciação 4E em Eucariotos , Animais , Ritmo Circadiano/fisiologia , Cognição , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Camundongos , Fosforilação , Transdução de Sinais , Núcleo Supraquiasmático/metabolismo
14.
Am Nat ; 199(4): E111-E123, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35324379

RESUMO

AbstractEnvironmental stress is one of the important causes of biological dispersal. At the same time, the process of dispersal itself can incur and/or increase susceptibility to stress for the dispersing individuals. Therefore, in principle, stress can serve as both a cause and a cost of dispersal. We studied these potentially contrasting roles of a key environmental stress (desiccation) using Drosophila melanogaster. By modulating water and rest availability, we asked whether (a) dispersers are individuals that are more susceptible to desiccation stress, (b) dispersers pay a cost in terms of reduced resistance to desiccation stress, (c) dispersal evolution alters the desiccation cost of dispersal, and (d) females pay a reproductive cost of dispersal. We found that desiccation was a clear cause of dispersal in both sexes, as both male and female dispersal propensity increased with increasing duration of desiccation. However, the desiccation cost of dispersal was male biased, a trend unaffected by dispersal evolution. Instead, females paid a fecundity cost of dispersal. We discuss the complex relationship between desiccation and dispersal, which can lead to both positive and negative associations. Furthermore, the sex differences highlighted here may translate into differences in movement patterns, thereby giving rise to sex-biased dispersal patterns.


Assuntos
Dessecação , Drosophila melanogaster , Animais , Feminino , Masculino , Reprodução , Caracteres Sexuais , Estresse Fisiológico
15.
Neurochem Res ; 47(2): 234-248, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34637100

RESUMO

Parkinson's disease (PD) is associated with dopamine depletion in the striatum owing to the selective and progressive loss of the nigrostriatal dopaminergic neurons, which results in motor dysfunction and secondary clinical manifestations. The dopamine level in the striatum is preserved because of the innervation of the substantia nigra (SN) dopaminergic neurons into it. Therefore, protection of the SN neurons is crucial for maintaining the dopamine level in the striatum and for ensuring the desired motor coordination. Several strategies have been devised to protect the degenerating dopaminergic neurons or to restore the dopamine levels for treating PD. Most of the methods focus exclusively on preventing cell body death in the neurons. Although advances have been made in understanding the disease, the search for disease-modifying drugs is an ongoing process. The present review describes the evidence from studies involving patients with PD as well as PD models that axon terminals are highly vulnerable to exogenous and endogenous insults and degenerate at the early stage of the disease. Impairment of mitochondrial dynamics, Ca2+ homeostasis, axonal transport, and loss of plasticity of axon terminals appear before the neuronal degeneration in PD. Furthermore, distortion of synaptic morphology and reduction of postsynaptic dendritic spines are the neuropathological hallmarks of early-stage disease. Thus, the review proposes a shift in focus from discerning the mechanism of neuronal cell body loss and targeting it to an entirely different approach of preventing axonal degeneration. The review also suggests appropriate strategies to prevent the loss of synaptic terminals, which could induce regrowth of the axon and its auxiliary fibers and might offer relief from the symptomatic features of PD.


Assuntos
Dopamina , Doença de Parkinson , Axônios/metabolismo , Corpo Estriado/metabolismo , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Humanos , Doença de Parkinson/metabolismo , Substância Negra/metabolismo
16.
Reprod Biomed Online ; 45(1): 10-13, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35523713

RESUMO

The last decade has seen an explosion of machine learning applications in healthcare, with mixed and sometimes harmful results despite much promise and associated hype. A significant reason for the reversal in the reported benefit of these applications is the premature implementation of machine learning algorithms in clinical practice. This paper argues the critical need for 'data solidarity' for machine learning for embryo selection. A recent Lancet and Financial Times commission defined data solidarity as 'an approach to the collection, use, and sharing of health data and data for health that safeguards individual human rights while building a culture of data justice and equity, and ensuring that the value of data is harnessed for public good' (Kickbusch et al., 2021).


Assuntos
Acesso à Informação , Justiça Social , Humanos , Aprendizado de Máquina
17.
Soft Matter ; 19(1): 98-105, 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36472188

RESUMO

N-doped graphene stabilized Cu(I)-catalyzed self-healing nanocomposites are developed. This study found the use of N-doped graphene as both a nanostructured material for enhancing mechanical and conductive properties and a catalyst promoter (a scaffold for catalytic copper(I) particles), helpful to trigger self-healing via "click chemistry". Due to an increase in electron density on nitrogen atom doping, including the coordination of N-doped rGO with Cu+ ions, nitrogen-doped graphene-supported copper particles demonstrate a higher reaction yield at room temperature without adding any external ligand/base. In this study, only one component (an azide moiety containing a healing agent) was encapsulated, whereas another component (an alkyne moiety containing a healing agent) was as such (without encapsulation) homogeneously dispersed in a matrix. Triggered capsule rupture then induces the contact of the healing agents with the N-doped graphene-based catalyst and the alkyne molecules dispersed in the matrix, inducing a "click"-reaction, allowing onsite damage to be repaired as determined by mechanical measurements entirely. Tensile measurements were also performed using molecular dynamics (MD) simulations to support the findings. Given the enormous importance of autonomic repair of materials damage, this concept here reports a trustworthy and reliable chemical system with a high level of robustness.

18.
PLoS Genet ; 15(7): e1008269, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31299050

RESUMO

Development of eye tissue is initiated by a conserved set of transcription factors termed retinal determination network (RDN). In the fruit fly Drosophila melanogaster, the zinc-finger transcription factor Glass acts directly downstream of the RDN to control identity of photoreceptor as well as non-photoreceptor cells. Tight control of spatial and temporal gene expression is a critical feature during development, cell-fate determination as well as maintenance of differentiated tissues. The molecular mechanisms that control expression of glass, however, remain largely unknown. We here identify complex regulatory mechanisms controlling expression of the glass locus. All information to recapitulate glass expression are contained in a compact 5.2 kb cis-acting genomic element by combining different cell-type specific and general enhancers with repressor elements. Moreover, the immature RNA of the locus contains an alternative small open reading frame (smORF) upstream of the actual glass translation start, resulting in a small peptide instead of the three possible Glass protein isoforms. CRISPR/Cas9-based mutagenesis shows that the smORF is not required for the formation of functioning photoreceptors, but is able to attenuate effects of glass misexpression. Furthermore, editing the genome to generate glass loci eliminating either one or two isoforms shows that only one of the three proteins is critical for formation of functioning photoreceptors, while removing the two other isoforms did not cause defects in developmental or photoreceptor function. Our results show that eye development and function is largely unaffected by targeted manipulations of critical features of the glass transcript, suggesting a strong selection pressure to allow the formation of a functioning eye.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Olho/crescimento & desenvolvimento , Processamento Alternativo , Animais , Diferenciação Celular , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Elementos Facilitadores Genéticos , Olho/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Mutagênese Sítio-Dirigida , Células Fotorreceptoras/metabolismo
19.
Drug Dev Res ; 83(7): 1469-1504, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35971890

RESUMO

With different nitrogen-containing heterocyclic moieties, Indazoles earn one of the places among the top investigated molecules in medicinal research. Indazole, an important fused aromatic heterocyclic system containing benzene and pyrazole ring with a chemical formula of C7 H6 N2 , is also called benzopyrazole. Indazoles consist of three tautomeric forms in which 1H-tautomers (indazoles) and 2H-tautomers (isoindazoles) exist in all phases. The tautomerism in indazoles greatly influences synthesis, reactivity, physical and even the biological properties of indazoles. The thermodynamic internal energy calculation of these tautomers points view 1H-indazole as the predominant and stable form over 2H-indazole. The natural source of indazole is limited and exists in alkaloidal nature (i.e., nigellidine, nigeglanine, nigellicine, etc.) found from Nigella plants. Some of the FDA-approved drugs like Axitinib, Entrectinib, Niraparib, Benzydamine, and Granisetron are being used to treat renal cell cancer, non-small cell lung cancer (NSCLC), epithelial ovarian cancer, chronic inflammation, chemotherapy-induced nausea, vomiting, and many more uses. Besides all these advantages regarding its biological activity, the main issue about indazoles is the less abundance in plant sources, and their synthetic derivatives also often face problems with low yield. In this review article, we discuss its chemistry, tautomerism along with their effects, different schematics for the synthesis of indazole derivatives, and their different biological activities.


Assuntos
Antineoplásicos , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Indazóis/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química
20.
Int J Mol Sci ; 23(11)2022 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-35682995

RESUMO

Approximately 50-80% of children with autism spectrum disorders (ASDs) exhibit sleep problems, but the contribution of circadian clock dysfunction to the development of ASDs remains largely unknown. The essential clock gene Bmal1 (Arntl or Mop3) has been associated with human sociability, and its missense mutation is found in ASD. Our recent study found that Bmal1-null mice exhibit a variety of autism-like phenotypes. Here, we further investigated whether an incomplete loss of Bmal1 function could cause significant autism-like behavioral changes in mice. Our results demonstrated that heterozygous Bmal1 deletion (Bmal1+/-) reduced the Bmal1 protein levels by ~50-75%. Reduced Bmal1 expression led to decreased levels of clock proteins, including Per1, Per2, Cry 1, and Clock but increased mTOR activities in the brain. Accordingly, Bmal1+/- mice exhibited aberrant ultrasonic vocalizations during maternal separation, deficits in sociability and social novelty, excessive repetitive behaviors, impairments in motor coordination, as well as increased anxiety-like behavior. The novel object recognition memory remained intact. Together, these results demonstrate that haploinsufficiency of Bmal1 can cause autism-like behavioral changes in mice, akin to those identified in Bmal1-null mice. This study provides further experimental evidence supporting a potential role for disrupted clock gene expression in the development of ASD.


Assuntos
Transtorno Autístico , Relógios Circadianos , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , Animais , Transtorno Autístico/genética , Encéfalo/metabolismo , Proteínas CLOCK/genética , Relógios Circadianos/genética , Ritmo Circadiano/genética , Haploinsuficiência , Privação Materna , Camundongos , Camundongos Knockout , Fenótipo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
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