Several neurodegenerative diseases present Tau accumulation as the main pathological marker. Tau post-translational modifications such as phosphorylation and acetylation are increased in ...neurodegeneration. Here, we show that Tau hyper-acetylation at residue 174 increases its own nuclear presence and is the result of DNA damage signaling or the lack of SIRT6, both causative of neurodegeneration. Tau-K174ac is deacetylated in the nucleus by SIRT6. However, lack of SIRT6 or chronic DNA damage results in nuclear Tau-K174ac accumulation. Once there, it induces global changes in gene expression, affecting protein translation, synthesis, and energy production. Concomitantly, Alzheimer’s disease (AD) case subjects show increased nucleolin and a decrease in SIRT6 levels. AD case subjects present increased levels of nuclear Tau, particularly Tau-K174ac. Our results suggest that increased Tau-K174ac in AD case subjects is the result of DNA damage signaling and SIRT6 depletion. We propose that Tau-K174ac toxicity is due to its increased stability, nuclear accumulation, and nucleolar dysfunction.
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•DNA damage or SIRT6 absence leads to acetylation of Tau-K174 via CBP•Tau174ac shuttles to the nucleus, where it induces nucleolar activation•SIRT6 regulates Tau-174ac nuclear functions through its deacetylation•Tau174Q increases nucleolar activity and protein synthesis, leading to ATP depletion
Portillo et al. show that acetylation of Tau-174 by CBP leads to its nuclear translocation, increasing nucleolar activity and protein synthesis capacity and resulting in ATP depletion. SIRT6 deacetylates nuclear Tau-174ac, preventing its accumulation. SIRT6 depletion, as in Alzheimer’s disease, increases Tau-174ac through the DNA damage response and impaired deacetylation.
The delivery of therapeutic proteins to selected sites within the central nervous system (CNS) parenchyma is a major challenge in the treatment of various neurodegenerative disorders. As ...brain-derived neurotrophic factor (BDNF) is reduced in the brain of people with Alzheimer's disease (AD) and its administration has shown promising therapeutic effects in mouse model of the disease, we generated a novel platform for T cell-based BDNF delivery into the brain parenchyma.
We generated amyloid beta-protein (Aβ)-specific CD4 T cells (Aβ-T cells), genetically engineered to express BDNF, and injected them intracerebroventricularly into the 5XFAD mouse model of AD.
The BDNF-secreting Aβ-T cells migrated efficiently to amyloid plaques, where they significantly increased the levels of BDNF, its receptor TrkB, and various synaptic proteins known to be reduced in AD. Furthermore, the injected mice demonstrated reduced levels of beta-secretase 1 (BACE1)—a protease essential in the cleavage process of the amyloid precursor protein—and ameliorated amyloid pathology and inflammation within the brain parenchyma.
A T cell-based delivery of proteins into the brain can serve as a platform to modulate neurotoxic inflammation and to promote neuronal repair in neurodegenerative diseases.
Consanguineous kindred presented with an autosomal recessive syndrome of intrauterine growth retardation, marked developmental delay, spastic quadriplegia with profound contractures, pseudobulbar ...palsy with recurrent aspirations, epilepsy, dysmorphism, neurosensory deafness and optic nerve atrophy with no eye fixation. Affected individuals died by the age of 4. Brain MRI demonstrated microcephaly, semilobar holoprosencephaly and agenesis of corpus callosum. We aimed at elucidating the molecular basis of this disease.
Genome-wide linkage analysis combined with whole exome sequencing were performed to identify disease-causing variants. Functional consequences were investigated in fruit flies null mutant for the
orthologue.
knockout SH-SY5Y and HEK293T cell-lines were generated using CRISPR/Cas9 and studied through qRT-PCR, immunoblotting and viability assays.
Through genetic studies, we identified a disease-associated homozygous nonsense mutation in
. We demonstrate that
is ubiquitously expressed, and that the mutation triggers nonsense-mediated decay of its transcript, comprising a practical null mutation. Similar to the human disease phenotype, knockdown
flies had defective brains and early lethality. Moreover, in line with
encoding one of the two coating layers comprising the Coat protein complex II (COP-II) complex, trafficking newly synthesised proteins from the endoplasmic reticulum (ER) to the Golgi, CRISPR/Cas9-mediated
null mutant cells demonstrated reduced viability through upregulation of ER-stress pathways.
We demonstrate through human and
genetic and in vitro molecular studies, that a severe neurological syndrome is caused by a null mutation in
, reducing cell viability through enhanced ER-stress response, in line with SEC31A's role in the COP-II complex.
Hyperinsulinism/hyperammonemia (HI/HA) syndrome has been known to be caused by dominant gain‐of‐function mutations in GLUD1, encoding the mitochondrial enzyme glutamate dehydrogenase. Pathogenic ...GLUD1 mutations enhance enzymatic activity by reducing its sensitivity to allosteric inhibition by GTP. Two recent independent studies showed that a similar HI/HA phenotype can be caused by biallelic mutations in SLC25A36, encoding pyrimidine nucleotide carrier 2 (PNC2), a mitochondrial nucleotide carrier that transports pyrimidine and guanine nucleotides across the inner mitochondrial membrane: one study reported a single case caused by a homozygous truncating mutation in SLC25A36 resulting in lack of expression of SLC25A36 in patients' fibroblasts. A second study described two siblings with a splice site mutation in SLC25A36, causing reduction of mitochondrial GTP content, putatively leading to hyperactivation of glutamate dehydrogenase. In an independent study, through combined linkage analysis and exome sequencing, we demonstrate in four individuals of two Bedouin Israeli related families the same disease‐causing SLC25A36 (NM_018155.3) c.284 + 3A > T homozygous splice‐site mutation found in the two siblings. We demonstrate that the mutation, while causing skipping of exon 3, does not abrogate expression of mRNA and protein of the mutant SLC25A36 in patients' blood and fibroblasts. Affected individuals had hyperinsulinism, hyperammonemia, borderline low birth weight, tonic–clonic seizures commencing around 6 months of age, yet normal intellect and no significant other morbidities. Chronic constipation, hypothyroidism, and developmental delay previously described in a single patient were not found. We thus verify that biallelic SLC25A36 mutations indeed cause HI/HA syndrome and clearly delineate the disease phenotype.
Networks of dry valleys (or balkas) and hollows in the upper reaches of fluvial basins in extraglacial areas in the Penultimate Glaciation (Marine Isotope Stage 6—MIS 6) regions of the East European ...Plain demonstrate clear incision/aggradation rhythms corresponding to global glacial/interglacial climate cycles. The first phase of each incision/aggradation rhythm began after the global glacial maximum and was characterized by a cool and humid climate, permafrost and sparse vegetation, when high surface runoff and active linear erosion formed a dense network of gullies. The second phase occurred at the glacial–interglacial transition and the subsequent interglacial period with its warm and humid climate and dense vegetation. This phase was distinguished by the partial filling of fluvial forms with slopewash deposits, the transformation of gullies into dry valleys (balkas) and the subsequent stabilization of fluvial forms marked by the formation of mature soils on the sides and bottoms of balkas. The third phase of the rapid accumulation of balkas developed during the cold and dry part of the next glacial epoch, resulting in the balkas becoming shallow hollows filled in with sediments. The last full incision/aggradation rhythm occurred in the late MIS 6 to mid-MIS 2. The erosion network formed during the late MIS 6 was almost completely filled by mid-MIS 2, and its manifestation in the modern topography is limited to a network of shallow hollows in the upper parts of the fluvial systems. The modern (incomplete) incision/aggradation rhythm began in the late MIS 2 and caused the formation of the modern erosion landscape in the upper reaches of fluvial systems. This rhythm is now in the stabilization phase, and the main accumulation phase of this rhythm is still far in the future.
Abstract Breast cancer (BC) is the leading cause of cancer-related deaths in women, with metastasis being the primary reason for BC mortality. Triple-Negative Breast Cancer (TNBC) is aggressive and ...highly metastatic, having fewer treatment options than other types of breast cancer. Protein kinase C eta (PKCη), an anti-apoptotic kinase of the novel PKC subfamily, is associated with poor prognosis in invasive BC patients. In this study, we show the role of PKCη in promoting cell migration and invasion, and we demonstrate that its expression is required to maintain the mesenchymal state during EMT. Furthermore, we show that PKCη activates YAP/TAZ, tumor aggressiveness, and metastasis using in vitro and in vivo models. PKCη promotes metastasis in TNBC cells, showing that the PKCƞ-YAP signaling axis mediates this. Data analysis of BC patients with a high metastatic invasive propensity and low survival BC revealed a positive correlation between the elevated expression levels of PKCη and the expression of YAP. Knockout of PKCη (PKCηKO) in the TNBC cells 4T1 and MDA-MB-231 markedly inhibited their invasion and migration capability. We further show that PKCη enhances cell survival and anoikis prevention ability, which have crucial roles in metastasis formation, allowing cancer cells to circulate and home to distant sites in the body. Further substantiated by in vivo experiments with 4T1 xenografts in NSG mice, demonstrating that 4T1 PKCηKO cells depicted reduced primary tumor size and a significant decrease in size and number of tumor metastases in the lungs, with fewer tumor nodules. MDA-MB-231 PKCηKO xenografts also expressed reduced metastasis in the distant brain, lung, and liver organs. Mechanistically, we show that PKCη regulates epithelial-to-mesenchymal transition (EMT) markers as knockout of PKCη in TNBC cell lines increased expression of E-cadherin, EpCAM, and slug, and decreased expression of vimentin and ZEB1. Further profiling of the Hippo-YAP axis showed that PKCη is a negative regulator of the Hippo pathway that leads to YAP stabilization and is associated with phosphorylation at Ser128, which allows YAP to translocate to the nucleus and contributes to metastasis of TNBC cells. Moreover, our data support direct interaction between PKCη and YAP1 in TNBC cells. Finally, we show that treatment of TNBC cells with uPEP2 (a uORF-encoded peptide of the PKCη transcript) downregulates the PKCη expression, activates the Hippo signaling pathway and promotes YAP degradation. Our findings highlight the importance of PKCη in TNBC metastasis and provide a new avenue for therapeutic intervention in this aggressive and lethal disease. In conclusion, our studies identify a novel role of PKCη as a negative regulator of the Hippo pathway and reveal its function in promoting EMT and metastasis by modulating YAP/TAZ activity in TNBC. Results suggest that PKCη may represent a therapeutic target for this highly lethal and metastatic TNBC. Citation Format: Liju Vijaya Steltar Belsamma, Amitha Muraleedharan, Divya Ram Jayaram, Kamran Waidha, Sankar Jagadeeshan, Rose Sinay, Ekaterina Eremenko, Omer Berner, Moshe Elkabets, Etta Livneh. Unravelling the role of PKC-eta in modulating the Hippo Pathway: a novel therapeutic strategy for triple-negative breast cancer metastasis abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-06-07.
It is currently believed that molecular agents that specifically bind to and neutralize the toxic proteins/peptides, amyloid β (Aβ42), tau, and the tau-derived peptide PHF6, hold the key to ...attenuating the progression of Alzheimer’s disease (AD). We thus tested our previously developed nonaggregating Aβ42 double mutant (Aβ42DM) as a multispecific binder for three AD-associated molecules, wild-type Aβ42, the tauK174Q mutant, and a synthetic PHF6 peptide. Aβ42DM acted as a functional inhibitor of these molecules in in vitro assays and in neuronal cell-based models of AD. The double mutant bound both cytotoxic tauK174Q and synthetic PHF6 and protected neuronal cells from the accumulation of tau in cell lysates and mitochondria. Aβ42DM also reduced toxic intracellular levels of calcium and the overall cell toxicity induced by overexpressed tau, synthetic PHF6, Aβ42, or a combination of PHF6and Aβ42. Aβ42DM inhibited PHF6-induced overall mitochondrial dysfunction: In particular, Aβ42DM inhibited PHF6-induced damage to submitochondrial particles (SMPs) and suppressed PHF6-induced elevation of the ζ-potential of inverted SMPs (proxy for the inner mitochondrial membrane, IMM). PHF6 reduced the lipid fluidity of cardiolipin/DOPC vesicles (that mimic the IMM) but not DOPC (which mimics the outer mitochondrial membrane), and this effect was inhibited by Aβ42DM. This inhibition may be explained by the conformational changes in PHF6 induced by Aβ42DM in solution and in membrane mimetics. On this basis, the paper presents a mechanistic explanation for the inhibitory activity of Aβ42DM against Aβ42- and tau-induced membrane permeability and cell toxicity and provides confirmatory evidence for its protective function in neuronal cells.
The quality of training of medical specialists is laid down during training at a medical university, where basic knowledge and the ability to manipulate them are laid, and, on the basis of the ...acquired competencies, to form practical skills. The issues of tuberculosis infection occupy a significant part in the work of a pediatrician. First of all, these are the issues of screening the child population for tuberculosis, early detection and specific prevention of tuberculosis. For the effective preparation of students of the pediatric faculty, it is necessary to lay theoretical knowledge in the program, to form practical skills and abilities. Since the detection of tuberculosis patients is carried out in medical institutions of the general pediatric network, it is necessary to master professional competencies. The preparation of students within the framework of the basic specialty "phthisiology" has its own nuances due to the specifics of medical education, the diversity of tuberculosis infection, the peculiarities of the organization and provision of anti-tuberculosis care to the child population. Training in the specialty "phthisiology" requires a large amount of special knowledge, skills, improvement of the interdisciplinary approach, in accordance with the requirements of the federal state educational standard. The article provides an analysis of the ongoing training system for students of the pediatric institute in the online system, presents the experience of the department in teaching students during the period of distance education during the spread of a new coronavirus infection. The assessment of the results of practical training among 6th year students of the pediatric faculty (n = 123). It was revealed that it is not always possible to predict in advance the degree of understanding of the educational material, and even the depth of understanding the questions in the test problems. The use of scientific evidence-based statistical methods for evaluating test items helps in optimizing and objectifying knowledge control and understanding the educational material.
Background: The delivery of therapeutic proteins to selected sites within the central nervous system (CNS) parenchyma is a major challenge in the treatment of various neurodegenerative disorders. As ...brain-derived neurotrophic factor (BDNF) is reduced in the brain of people with Alzheimer's disease (AD) and its administration has shown promising therapeutic effects in mouse model of the disease, we generated a novel platform for T cell-based BDNF delivery into the brain parenchyma. Methods: We generated amyloid beta-protein (Aβ)-specific CD4 T cells (Aβ-T cells), genetically engineered to express BDNF, and injected them intracerebroventricularly into the 5XFAD mouse model of AD. Findings: The BDNF-secreting Aβ-T cells migrated efficiently to amyloid plaques, where they significantly increased the levels of BDNF, its receptor TrkB, and various synaptic proteins known to be reduced in AD. Furthermore, the injected mice demonstrated reduced levels of beta-secretase 1 (BACE1)—a protease essential in the cleavage process of the amyloid precursor protein—and ameliorated amyloid pathology and inflammation within the brain parenchyma. Interpretation: A T cell-based delivery of proteins into the brain can serve as a platform to modulate neurotoxic inflammation and to promote neuronal repair in neurodegenerative diseases. Keywords: Cell-based delivery, CD4 T cell, BDNF, CNS, Brain, Alzheimer's disease, Amyloid plaques, Targeted drug delivery
Currently, with the improvement of epidemic indicators for tuberculosis, the number of patients with drug-resistant forms of tuberculosis is increasing, which complicates and prolongs the treatment ...of such patients. The aim of the work is to study the drug resistance of Mycobacterium tuberculosis obtained from surgical material. Materials and methods: the study included 74 patients with medical and diagnostic operations on the chest organs. All patients were examined by standard methods: sputum and BAL microscopy with bronchoscopy (during the procedure), molecular genetic methods, culture on dense and liquid nutrient media. The diagnosis of tuberculosis was confirmed morphologically in all patients by histological examination of surgical material. When analyzing the results of drug resistance, it was found that among the newly identified patients, more than half (59.3%) had multiple (44.6%) p<0.005 and extensively drug resistance (14.7%) p= 0.003. At the same time, 74.5% (n= 35/47) of patients had no MBT in sputum before surgery. The frequency of development of drug resistance to first-and reserve-line antibacterial drugs, the structure of drug resistance depending on the group of dispensary registration is presented. A comparative analysis of drug sensitivity testing of MBT isolated from sputum before surgery and from surgical material was performed. The results of the study showed a high percentage of MBT drug resistance obtained in the operating material in patients with negative MBT tests. More than half of the patients who did not receive antibacterial therapy before surgery have multi drug resistance and extensively drug resistance, which suggests a high regional primary drug resistance of Mycobacterium tuberculosis.
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