Processing of amyloid-β (Aβ) precursor protein (APP) by γ-secretase produces multiple species of Aβ: Aβ40, short Aβ peptides (Aβ37-39), and longer Aβ peptides (Aβ42-43). γ-Secretase modulators, a ...class of Alzheimer's disease therapeutics, reduce production of the pathogenic Aβ42 but increase the relative abundance of short Aβ peptides. To evaluate the pathological relevance of these peptides, we expressed Aβ36-40 and Aβ42-43 in
to evaluate inherent toxicity and potential modulatory effects on Aβ42 toxicity. In contrast to Aβ42, the short Aβ peptides were not toxic and, when coexpressed with Aβ42, were protective in a dose-dependent fashion. In parallel, we explored the effects of recombinant adeno-associated virus-mediated expression of Aβ38 and Aβ40 in mice. When expressed in nontransgenic mice at levels sufficient to drive Aβ42 deposition, Aβ38 and Aβ40 did not deposit or cause behavioral alterations. These studies indicate that treatments that lower Aβ42 by raising the levels of short Aβ peptides could attenuate the toxic effects of Aβ42.
The ability to manipulate expression of exogenous genes in particular regions of living organisms has profoundly transformed the way we study biomolecular processes involved in both normal ...development and disease. Unfortunately, most of the classical inducible systems lack fine spatial and temporal accuracy, thereby limiting the study of molecular events that strongly depend on time, duration of activation, or cellular localization. By exploiting genetically engineered photo sensing proteins that respond to specific wavelengths, we can now provide acute control of numerous molecular activities with unprecedented precision. In this review, we present a comprehensive breakdown of all of the current optogenetic systems adapted to regulate gene expression in both unicellular and multicellular organisms. We focus on the advantages and disadvantages of these different tools and discuss current and future challenges in the successful translation to more complex organisms.
•We determined the association of rs356165–rs11931074 and PD-risk in a Spanish cohort.•We measured the RNA levels of the four SNCA isoforms in postmortem brain tissues.•We did not find a correlation ...of genotype with isoforms level.•We found a tendency of higher levels of the three short SNCA isoforms in the SN of PD brains.
Mutations in the alpha-synuclein (SNCA) gene cause autosomal dominant Parkinson's disease (PD). Common SNCA polymorphisms have been associated with the risk of developing PD. Abnormal expression and post-translational modification of SNCA has been found in PD-brains. In addition to a full length transcript (SNCA-140) there are three short isoforms (SNCA-98, -112, and -126) that could be prone to aggregation. The association between SNCA polymorphisms and PD could be explained through an increased expression of these alternative transcripts. Our aim was to measure the different SNCA transcripts in the substantia nigra (SN), cerebellum (CB), and occipital cortex (OC) from PD-patients (n=9) and healthy subjects (n=6). In addition, we determined whether two SNCA polymorphisms (SNPs rs356165 and rs11931074) were related to differences in transcript isoform expression. PD brain tissues showed higher levels of the three short transcripts in the SN, but only SNCA-112 and SNCA-98 were significantly increased in the CB of patients vs. controls (p=0.02, p=0.03). The genotyping of a large cohort of PD-patients and controls showed that haplotype rs356165-A+rs11931074-G had a protective effect (OR=0.71; CI=0.59–0.83), while the G-T haplotype increased the risk for PD (OR=1.44; CI=1.06–1.96). We did not find significant differences for the SNCA levels between the haplotypes. In conclusion, we found statistically significant higher levels of the SNCA-112 and SNCA-98 transcripts in the CB of PD brains, and a trend toward higher levels of the short transcript isoforms in the SN of PD brains.
Resumen En la región México-Estados Unidos las políticas para controlar y disuadir los desplazamientos migratorios irregulares han alcanzado también a los buscadores de asilo quienes en los últimos ...años viven un limbo de inmovilidad y desprotección, ahora agravado por la pandemia de la COVID-19. En este artículo se analizan las implicaciones del programa MPP, del sistema de refugio en México y de la crisis sanitaria sobre las personas con necesidades de protección internacional. Los resultados muestran cómo las restricciones y ralentización de los procesos de asilo y refugio han generado distintas condiciones de atrapamiento, mientras la pandemia acentuó el enfoque de securitización migratoria en torno a un riesgo que debe ser contenido.
Abstract In the Mexico-United States region, policies to control and deter irregular migratory movements have also reached asylum seekers who in recent years have been living in a limbo of immobility and lack of protection, now aggravated by the COVID-19 pandemic. This article analyzes the implications of the MPP program, the refugee system in Mexico and the health crisis on people with international protection needs. The results show how the restrictions and slowdown of the asylum and refugee processes have generated different entrapment conditions, while the pandemic accentuated the immigration securitization approach around a risk that must be contained.
Mortalin is a mitochondrial chaperone of the heat shock protein 70 family. Mortalin plays a central role in mitochondrial biogenesis through its capacity to direct the import of nuclear-encoded ...proteins into the mitochondria. As mitochondrial dysfunction has been involved in Parkinson’s disease (PD), changes in mortalin function and expression could manifest as a higher risk of developing PD. In agreement with this, mortalin expression was decreased in the mitochondrial fraction of neurons from the
substantia nigra
of PD patients. We hypothesised that DNA variants in the mortalin gene (HSPA9) could contribute to the risk of developing PD. We analysed the 17 HSPA9 coding exons in 330 PD patients and 250 controls. In addition to several polymorphisms, found in patients and controls, three variants were found in 3 patients but none of the controls: two missense (R126 > W and P509 > S) and a 17 bp insertion in intron 8 (predicted to affect RNA splicing). Our study suggests that putative mutations in the mortalin, although rare, could contribute to the risk of developing PD.
Nuclear depletion, abnormal modification, and cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP-43) are linked to a group of fatal neurodegenerative diseases called TDP-43 proteinopathies, ...which include amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Although our understanding of the physiological function of TDP-43 is rapidly advancing, the molecular mechanisms associated with its pathogenesis remain poorly understood. Accumulating evidence suggests that endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are important players in TDP-43 pathology. However, while neurons derived from autopsied ALS and FTLD patients revealed TDP-43 deposits in the ER and displayed UPR activation, data originated from
and
TDP-43 models produced contradictory results. In this review, we will explore the complex interplay between TDP-43 pathology, ER stress, and the UPR by breaking down the evidence available in the literature and addressing the reasons behind these discrepancies. We also highlight underexplored areas and key unanswered questions in the field. A better synchronization and integration of methodologies, models, and mechanistic pathways will be crucial to discover the true nature of the TDP-43 and ER stress relationship and, ultimately, to uncover the full therapeutic potential of the UPR.
Clinical and cognitive progression in alpha-synucleinopathies is highly heterogeneous. While some patients remain stable over long periods of time, other suffer early dementia or fast motor ...deterioration. Sleep disturbances and nocturnal blood pressure abnormalities have been identified as independent risk factors for clinical progression but a mechanistic explanation linking both aspects is lacking. We hypothesize that impaired glymphatic system might play a key role on clinical progression. Glymphatic system clears brain waste during specific sleep stages, being blood pressure the motive force that propels the interstitial fluid through brain tissue to remove protein waste. Thus, the combination of severe sleep alterations, such as REM sleep behavioral disorder, and lack of the physiological nocturnal decrease of blood pressure due to severe dysautonomia may constitute the perfect storm for glymphatic failure, causing increased abnormal protein aggregation and spreading. In Lewy body disorders (Parkinson’s disease and dementia with Lewy bodies) the increment of intraneuronal alpha-synuclein and extracellular amyloid-β would lead to cognitive deterioration, while in multisystemic atrophy, increased pathology in oligodendroglia would relate to the faster and malignant motor progression. We present a research model that may help in developing studies aiming to elucidate the role of glymphatic function and associated factors mainly in alpha-synucleinopathies, but that could be relevant also for other protein accumulation-related neurodegenerative diseases. If the model is proven to be useful could open new lines for treatments targeting glymphatic function (for example through control of nocturnal blood pressure) with the objective to ameliorate cognitive and motor progression in alpha-synucleinopathies.
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