Conditioned Medium from Cells Overexpressing TDP-43 Alters the Metabolome of Recipient Cells

Casein kinase 1 inhibitor avoids TDP-43 pathology propagation in a patient-derived cellular model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease without a cure to reverse its progression. Its main hallmark is the nuclear protein TDP-43, which undergoes different post-translational modifications leading to a loss of function in the nucleus and an increase in toxicity in the cytoplasm. Previous reports have indicated that pathogenic TDP-43 exhibits prion-like propagation in various contexts. With the aim of advancing therapeutics focused on preventing the propagation of TDP-43 pathology, we studied the potential role of pathogenic TDP-43 in lymphoblasts from sporadic ALS patients. We used lymphoblastoid cell lines from sporadic ALS patients as a source of pathogenic forms of TDP-43, and healthy human cells (lymphoblasts, myoblasts, neuroblastoma SH-SY5Y, or osteosarcoma U2OS) as recipient cells to investigate the seeding and spread of TDP-43 proteinopathy. Furthermore, we evaluated the potential of targeting TDP-43 phosphorylation with a CK-1 inhibitor to prevent the propagation of the pathology. The results presented herein indicate that pathogenic forms of TDP-43 are secreted into the extracellular medium of sporadic ALS lymphoblasts and could be transported by extracellular vesicles, spreading TDP-43 pathology to healthy cells. Moreover, tunneling nanotubes have also been discovered in pathological cells and may be involved in the transport of TDP-43. Interestingly, targeting TDP-43 phosphorylation with an in-house designed CK-1 inhibitor (IGS2.7) was sufficient to halt TDP-43 pathology transmission, in addition to its known effects on restoring the homeostasis of TDP-43 protein in patients-derived cells.

Porcine cardiac blood - Salvia miltiorrhiza root alleviates cerebral ischemia reperfusion injury by inhibiting oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza Bge. mixed with porcine cardiac blood (PCB-DS) is mainly employed for the treatment of brain ischemia-induced mental disturbances, palpitations and phlegm confusion based on the traditional principle of Menghe medical sect. PCB is the guide to DS and enhances the effect of DS. However, the potential mechanism of PCB-DS preventing cerebral ischemia/reperfusion injury (CIRI) from the perspective of oxidative stress induced cell apoptosis remains unknown.

AIM OF THE STUDY

To investigate the pharmacological activity and molecular mechanism of PCB-DS against CIRI.

MATERIALS AND METHODS

DS samples processed with different methods were prepared and UPLC-Q-TOF-MS/MS was employed for qualitative analysis of the respective processing product. The middle cerebral artery occlusion reperfusion model was then established to investigate the pharmacological activities of PCB-DS. Pathological changes in the rat brain were observed by triphenyl tetrazolium chloride (TTC), hematoxylin-eosin, and TUNEL staining. The levels of IL-6, IL-1β, and TNF-α were detected by ELISA to evaluate the inflammatory damage. Metabolomics of cerebrospinal fluid was further used to explore the potential mechanism of PCB-DS in preventing CIRI. Based on this, the levels of oxidative stress-related lactate dehydrogenase (LDH), reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined. The protein levels of PI3K, AKT, Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9 proteins of the cerebral infarct zone were finally measured by western blotting.

RESULTS

Forty-seven components were identified in four processing products. Compared to DS, the content of total aqueous components in PCB-DS was significantly increased including salvianolic acid B isomer, salvianolic acid D, salvianolic acid F, and salvianolic acid H/I/J. Among the DS, DS processed with wine, DS processed with pig blood, and DS processed with porcine cardiac blood, PCB-DS best alleviated the CIRI through the neurological score, brain infarct volume, brain histopathology and the levels of inflammatory factors in the brain. Twenty-five significant metabolites in the cerebrospinal fluid were screened out between the sham and I/R groups. They were mainly involved in the beta-alanine metabolism, histidine metabolism, and lysine degradation, which indicated that PCB-DS may inhibit oxidative stress-induced apoptosis to achieve treating ischemic stroke. The results of biomedical examination showed that PCB-DS could alleviate oxidative damage, significantly downregulate the expression of Bax, cleaved caspase-3 and cleaved caspase-9, and upregulate the expression of p-PI3K, p-AKT, and Bcl-2.

CONCLUSION

In summary, this study demonstrated that PCB-DS alleviated CIRI and the molecular mechanism may be related to inhibiting the oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway.

DNAJA1 Dysregulates Metabolism Promoting an Antiapoptotic Phenotype in Pancreatic Ductal Adenocarcinoma

The cochaperone protein DNAJA1 (HSP40) is downregulated four-fold in pancreatic cancer cells. The impact of DNAJA1 expression on pancreatic ductal adenocarcinoma (PDAC) progression remains unclear. The metabolic impacts of increased DNAJA1 expression were evaluated using a combination of untargeted metabolomics, stable isotope-resolved metabolomics (SIRM), confocal microscopy, flow cytometry, and cell-based assays. Differential Warburg glycolysis, an increase in redox currency, and alterations in amino acid levels were observed in both overexpression cell lines. DNAJA1 overexpression also led to mitochondrial fusion, an increase in the expression of Bcl-2, a modest protection from redox-induced cell death, a loss of structural integrity due to the loss of actin fibers, and an increase in cell invasiveness in BxPC-3. These differences were more pronounced in BxPC-3, which contains a loss-of-function mutation in the tumor-suppressing gene SMAD4. These findings suggest a proto-oncogenic role of DNAJA1 in PDAC progression and suggest DNAJA1 may function synergistically with other proteins with altered activities in pancreatic cancer cell lines.

Mechanisms of TDP-43 Proteinopathy Onset and Propagation

TDP-43 is an RNA-binding protein that has been robustly linked to the pathogenesis of a number of neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal dementia. While mutations in the TARDBP gene that codes for the protein have been identified as causing disease in a small subset of patients, TDP-43 proteinopathy is present in the majority of cases regardless of mutation status. This raises key questions regarding the mechanisms by which TDP-43 proteinopathy arises and spreads throughout the central nervous system. Numerous studies have explored the role of a variety of cellular functions on the disease process, and nucleocytoplasmic transport, protein homeostasis, RNA interactions and cellular stress have all risen to the forefront as possible contributors to the initiation of TDP-43 pathogenesis. There is also a small but growing body of evidence suggesting that aggregation-prone TDP-43 can recruit physiological TDP-43, and be transmitted intercellularly, providing a mechanism whereby small-scale proteinopathy spreads from cell to cell, reflecting the spread of clinical symptoms observed in patients. This review will discuss the potential role of the aforementioned cellular functions in TDP-43 pathogenesis, and explore how aberrant pathology may spread, and result in a feed-forward cascade effect, leading to robust TDP-43 proteinopathy and disease.