Serine 39 in the GTP-binding domain of Drp1 is involved in shaping mitochondrial morphology.

Continuous fusion and fission are critical for mitochondrial health. In this study, we further characterize the role played by dynamin-related protein 1 (Drp1) in mitochondrial fission. We show that a single amino acid change in Drp1 at position 39 from serine to alanine (S39A) within the GTP-binding (GTPase) domain results in a fused mitochondrial network in human SH-SY5Y neuroblastoma cells. Interestingly, the phosphorylation of Ser-616 and Ser-637 of Drp1 remains unaffected by the S39A mutation, and mitochondrial bioenergetic profile and cell viability in the S39A mutant were comparable to those observed in the control. This leads us to propose that the serine 39 residue of Drp1 plays a crucial role in mitochondrial distribution through its involvement in the GTPase activity. Furthermore, this amino acid mutation leads to structural anomalies in the mitochondrial network. Taken together, our results contribute to a better understanding of the function of the Drp1 protein.

Stable knockdown of Drp1 improves retinoic acid-BDNF-induced neuronal differentiation through global transcriptomic changes and results in reduced phosphorylation of ERK1/2 independently of DUSP1 and 6.

Background: Dynamin-related protein Drp1 -a major mitochondrial fission protein- is widely distributed in the central nervous system and plays a crucial role in regulating mitochondrial dynamics, specifically mitochondrial fission and the organelle's shaping. Upregulated Drp1 function may contribute to the pathological progression of neurodegenerative diseases by dysregulating mitochondrial fission/ fusion. The study aims to investigate the effects of Drp1 on retinoic acid-BDNF-induced (RA-BDNF) neuronal differentiation and mitochondrial network reorganization in SH-SY5Y neuroblastoma cells. Methods: We generated an SH-SY5Y cell line with stably depleted Drp1 (shDrp1). We applied RNA sequencing and analysis to study changes in gene expression upon stable Drp1 knockdown. We visualized the mitochondria by transmission electron microscopy and used high-content confocal imaging to characterize and analyze cell morphology changes and mitochondrial network reorganization during neuronal differentiation. Results: shDrp1 cells exhibited fused mitochondrial ultrastructure with perinuclear clustering. Stable knockdown of Drp1 resulted in the upregulation of genes involved in nervous system development. High content analysis showed improved neurite outgrowth, segmentation, and extremities in differentiated shDrp1 cells. Neuronal differentiation was associated with a significant reduction in ERK1/2 phosphorylation, and ERK1/2 phosphorylation was independent of the dual specificity phosphatases DUSP1/6 in shDrp1 cells. Differentiated control underwent mitochondrial morphology remodeling, whereas differentiated shDrp1 cells retained the highly fused mitochondria and developed long, elongated structures. The shDrp1 cells responded to specific apoptotic stimuli like control in vitro, suggesting that Drp1 is not a prerequisite for apoptosis in SH-SY5Y cells. Moreover, Drp1 downregulation reduced the formation of toxic mHtt aggregates in vitro. Discussion: Our results indicate that Drp1 silencing enhances RA-BDNF-induced neuronal differentiation by promoting transcriptional and mitochondrial network changes in undifferentiated cells. We also demonstrate that the suppression of Drp1 reduces toxic mHtt aggregate formation in vitro, suggesting protection against neurotoxicity. Thus, Drp1 may be an attractive target for further investigation in future strategies to combat neurodegenerative diseases.

Highly biocompatible formulations based on Arabic gum Nano composite hydrogels: Fabrication, characterization, and biological investigation.

In the study, fabrication of Arabic gum (AG) hydrogels via reverse micellization method is reported. AG hydrogels were utilized as capping agents to encapsulate zinc sulphide (ZnS), and cadmium sulphide (CdS) nanoparticles via in-situ reduction. Pristine and nanocomposite hydrogels (AG-ZnS and AG-CdS) were characterized through SEM, EDX, TEM, XRD, FTIR, TGA, UV/Visible, and photoluminescence spectroscopy. The hydrogels were subjected to multiple biological assays including antimicrobial, antioxidant, and anti-diabetic formulation, in addition to biocompatibility test. The hydrogels were found to be more effective against bacterial and fungal strains. For instance, AG-ZnS exhibited excellent growth inhibition activity against Escherichia coli (ZoI: 12 ± 1.04 mm) and Candida albicans (35 ± 0.94 mm). Likewise, the nanocomposites hydrogel also displayed excellent DPPH and ABTS free radical scavenging capacity, total antioxidant capacity (TAC), and total reducing power (TRP) ability. Among the hydrogels, AG-ZnS demonstrated considerable α-amylase, and α-glucosidase inhibition potential. Above all, the hydrogels were found highly compatible with human red blood cells (hRBCs). Owing to remarkable antioxidant, antibacterial, antifungal, and bio-compatible nature, the fabricated nanocomposites hydrogels have the potential to be explored in tissue engineering, wound healing, drug delivery, and in environmentally friendly hygiene products.

Synthesis, characterization, and biological screening of metal nanoparticles loaded gum acacia microgels.

We report novel gum acacia (GA) based microgels composites for multifunctional biomedical application. High yield of spherical GA microgels particles within 5-50 µm size range was obtained via crosslinking the polymer in the reverse micelles of surfactant-sodium bis (2-ethylhexyl) sulfosuccinate (NBSS) in gasoline medium. The prepared microgels were then utilized for in situ silver (Ag) and cobalt (Co) nanoparticles (NPs) synthesis to subsequently produce GNAg and GNCo nanocomposite microgels, respectively. Ag and Co NPs of particle of almost less than 40 nm sizes were homogenously distributed over the matrices of the prepared microgels, and therefore, negligible agglomeration effect was observed. Pristine GA microgels, and the nanocomposite microgels were thoroughly characterized through FTIR, DSC, TGA, XRD, SEM, EDS, and TEM. The well-characterized pristine GA microgels and the nanocomposite microgels were then subjected to multiple in vitro bioassays including antioxidant, antidiabetic, and antimicrobial activities as well as biocompatibility investigation. Our results demonstrate that the prepared nanocomposites in particular GNAg microgels exhibited excellent biomedical properties as compared to pristine GA microgels. Among the prepared samples, GNAg nanocomposites were highly active against Fusarium oxysporum and Aspergillus niger that show 47.73% ± 0.25 inhibition and 32.3% ± 2.0 with IC-50 of 220 µg ml-1 and 343 µg ml-1 , respectively. Moderate antidiabetic activity was also observed for GNAg nanocomposites with considerable inhibition of 15.34% ± 0.20 and 14.7% ± 0.44 for both α-glucosidase and α-amylase, respectively. Moreover, excellent antioxidant properties were found for both the GNAg and GNCo nanocomposites as compared to pristine GA microgels. A remarkable biocompatible nature of the nanocomposites in particular GNAg makes the novel GA composites, to be exploited for diverse biomedical applications.

The Proteasome Activators Blm10/PA200 Enhance the Proteasomal Degradation of N-Terminal Huntingtin.

The Blm10/PA200 family of proteasome activators modulates the peptidase activity of the core particle (20S CP). They participate in opening the 20S CP gate, thus facilitating the degradation of unstructured proteins such as tau and Dnm1 in a ubiquitin- and ATP-independent manner. Furthermore, PA200 also participates in the degradation of acetylated histones. In our study, we use a combination of yeast and human cell systems to investigate the role of Blm10/PA200 in the degradation of N-terminal Huntingtin fragments (N-Htt). We demonstrate that the human PA200 binds to N-Htt. The loss of Blm10 in yeast or PA200 in human cells results in increased mutant N-Htt aggregate formation and elevated cellular toxicity. Furthermore, Blm10 in vitro accelerates the proteasomal degradation of soluble N-Htt. Collectively, our data suggest N-Htt as a new substrate for Blm10/PA200-proteasomes and point to new approaches in Huntington's disease (HD) research.

Evaluation of biological activities and in vivo amelioration of CCl4 induced toxicity in lung and kidney with Abutilon pannosum (G.Forst.) Schltdl. in rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Abutilon pannosum is used in Pakistan for bladder inflammation, diuretic, lung disorders, diabetes and in lowering pyrexia. METHODS: Amount of total phenolic content, total flavonoid content and HPLC analysis of APM for the presence of polyphenolics were carried out. Antioxidant activity was determined by using different in vitro antioxidant assays. Amelioration effects of APM (200 mg/kg body weight and 400 mg/kg body weight) against CCl4 induced kidney and lung toxicity in rat was assessed by determining level of antioxidant enzymes, lipid peroxidation products, cytokines (TNF-α, IL-1ß and IL-2), comet assay and histological analysis. RESULTS: HPLC-DAD studies of APM indicated the presence of rutin (0.635 ± 0.011 µg/mg dry extract), gallic acid (1.07 ± 0.043 µg/mg dry extract) and catechin (0.246 ± 0.08 µg/mg dry extract) and considerable quantity of total phenolic (55.485 ± 0.85 mg GAE/g dry extract) and total flavonoid content (19.90 ± 0.58 mg Rutin/g dry extract). During in vitro antioxidant assays APM showed significant (p < 0.05) activity for iron chelation, reducing potential, inhibition of ß-carotene oxidation while moderate potential for scavenging of DPPH, hydroxyl, nitrite and phosphomolybdenum radical. Administration of CCl4 to rat severely depleted the activity level of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), and reduced glutathione (GSH) concentration while appreciably increased the concentration of thiobarbituric acid reactive substances (TBARS), H2O2, nitrite, TNF-α, IL-1ß and IL-2 in lung and kidney tissues of rat. Comet length, % DNA in tail and tail moment significantly (p < 0.01) increased in lung and kidney cells of CCl4 intoxicated rat. Further, injuries in lung and kidney tissues were recorded with CCl4 induced toxicity in rat. The rats treated with APM along with CCl4 exhibited an appreciable level of restoration of the altered parameters towards the control animals. CONCLUSION: The results of this study suggested the protective potential of APM in CCl4 intoxicated rats for kidney and lung injuries.

Abutilon pannosum stem bark enhances the aphrodisiac activities and spermatogenesis in rat.

Abutilon pannosum (Forst.f.) Schlecht. is used for male sexual performance. In this study, we have investigated aphrodisiac potential of A. pannosum stem bark methanol extract (APM) in rat. Male rats were administered with APM (400 mg/kg) on daily basis for 5, 10 and 15 days. Time interval for mount latency, intromission latency and post-ejaculatory interval was decreased (p < .05) while time of ejaculatory latency, mount frequency, intromission frequency and ejaculatory frequency after 15 days were (p < .05) enhanced as compared to control rats. APM also increased (p < .05) penile erection index, copulatory rate and mount bout against control rats. Total count of spermatozoa was nonsignificantly increased whereas per cent of live spermatozoa and motile spermatozoa were increased (p < .05) in APM treated group after 10 and 15 days. Weight of testes, seminal vesicle, prostate and epididymis, and level of testosterone in serum increased (p < .05) after 10 and 15 days of APM administration to rat. Qualitative characterisation of APM indicated existence of alkaloids, terpenoids, coumarins, cardiac glycosides, phenols, flavonoids, saponins, tannins and sterols. Results of this study indicated aphrodisiac potential of A. pannosum in rat and may be used to enhance sexual performance in human.