Ferroptosis inhibition protects vascular endothelial cells and maintains integrity of the blood-spinal cord barrier after spinal cord injury

Maintaining the integrity of the blood-spinal cord barrier is critical for the recove ry of spinal cord injury.Ferro ptosis contributes to the pathogenesis of spinal cord injury.We hypothesized that ferroptosis is involved in disruption of the blood-s pinal cord barrier.In this study,we administe red the ferroptosis inhibitor liproxstatin-1 intraperitoneally after contusive spinal co rd injury in rats.Liproxstatin-1 improved locomotor recovery and somatosensory evoked potential electrophysiological performance after spinal cord inju ry.Liproxstatin-1 maintained blood-spinal cord barrier integrity by upregulation of the expression of tight junction protein.Liproxstatin-1 inhibited ferroptosis of endothelial cell after spinal cord injury,as shown by the immunofluorescence of an endothelial cell marker(rat endothelium cell antigen-1,RECA-1) and fe rroptosis markers Acyl-CoA synthetase long-chain family member 4 and 15-lipoxygenase.Liproxstatin-1reduced brain endothelial cell ferroptosis in vitro by upregulating glutathione peroxidase 4 and downregulating Acyl-CoA synthetase long-chain family member4 and 15-lipoxygenase.Furthermore,inflammatory cell recruitment and astrogliosis were mitigated after liproxstatin-1 treatment.In summary,liproxstatin-1im proved spinal cord injury recovery by inhibiting ferroptosis in endothelial cells and maintaining blood-s pinal co rd barrier integrity.

The Comparison of Genetic Variation in the Envelope Protein Between Various Immunodeficiency Viruses and Equine Infectious Anemia Virus

The envelope protein （Env） of lentiviruses such as HIV, SIV, FIV and EIAV is larger than that of other retroviruses. The Chinese EIAV attenuated vaccine is based on Env and has helped to successfully control this virus, demonstrating that envelope is crucial for vaccine. We compared Env variation of the four kinds of lentiviruses. Phylogenetic analysis showed that the evolutionary relationship of Env between HIV and SIV was the closest and they appeared to descend from a common ancestor, and the relationship of HIV and EIAV was the furthest. EIAV had the shortest Env length and the least number of potential N-linked glyeosylation sites （PNGS） as well as glyeosylation density compared to various immunodefieiency viruses. However, HIV had the longest Env length and the most PNGS. Moreover, the alignment of HIV and SIV showed that PNGS were primarily distributed within extraeellular membrane protein gp120 rather than transmembrane gp41. It implies that the size difference among these viruses is associated with a lentivirus specific function and also the diversity of env. There arc low levels of modification of glycosylation sites of Env and selection of optimal protective epitopes might be useful for development of an effective vaccine against HIV/AIDS.

Transactivating-transduction protein-polyethylene glycol modified liposomes traverse the blood-spinal cord and blood-brain barriers

Naive liposomes can cross the blood-brain barrier and blood-spinal cord barrier in small amounts. Liposomes modified by a transactivating-transduction protein can deliver antibiotics for the treatment of acute bacterial infection-induced brain inflammation. Liposomes conjugated with polyethylene glycol have the capability of long-term circulation. In this study we prepared transactivating-transduction protein-polyethylene glycol-modified liposomes labeled with fiuorescein isothiocyanate. Thus, liposomes were characterized by transmembrane, long-term circulation and fluorescence tracing. Uptake, cytotoxicity, and the ability of traversing blood-spinal cord and blood-brain barriers were observed following coculture with human breast adenocarcinoma cells （MCF-7）. Results demonstrated that the liposomes had good biocompatibility, and low cytotoxicity when cocultured with human breast adenocarcinoma cells. Liposomes could traverse cell membranes and entered the central nervous system and neurocytes through the blood-spinal cord and blood-brain barriers of rats via the systemic circulation. These results verified that fluorescein isothiocyanate-modified transactivating-transduction protein-polyethylene glycol liposomes have the ability to traverse the blood-spinal cord and blood-brain barriers.

Two Retroviruses Packaged in One Cell Line can Combined Inhibit the Replication of HIV-1 in TZM-bl Cells

The cellular protein tetherin tethers the HIV-1 viral particles on the cellular membrane to inhibit the replication of HIV-1. However, the HIV-1 accessory protein Vpu counteracts the antiviral function of tetherin. In this study, two retroviral vector plasmids were constructed. One inhibited the vpu gene expression; the other one over-expressed the tetherin. Both retroviral vector plasmids could be packaged in the packaging cell line PT67 to obtain the corresponding retroviruses. The retroviral vector plasmids＇ functions of tetherin over-expression or vpu-RNAi were detected at the cell level. Retroviral vector plasmids were transfected to PT67 cells at different ratios from 0T3V to 3TOV, and then mixed retroviruses were harvested. The antiviral functions of mixed retroviruses were detected in HIV-1 infected TZM-bi cells. The results showed that packaged mixed retroviruses could repress the replication of HIV-1 in TZM-bl cells.

Autologous exosome facilitates load and target delivery of bioactive peptides to repair spinal cord injury

Spinal cord injury(SCI)causes motor,sensory and automatic impairment due to rarely axon regeneration.Developing effective treatment for SCI in the clinic is extremely challenging because of the restrictive axonal regenerative ability and disconnection of neural elements after injury,as well as the limited systemic drug delivery efficiency caused by blood spinal cord barrier.To develop an effective non-invasive treatment strategy for SCI in clinic,we generated an autologous plasma exosome(AP-EXO)based biological scaffold where AP-EXO was loaded with neuron targeting peptide(RVG)and growth-facilitating peptides(ILP and ISP).This scaffold can be targeted delivered to neurons in the injured area and elicit robust axon regrowth across the lesion core to the levels over 30-fold greater than naïve treatment,thus reestablish the intraspinal circuits and promote motor functional recovery after spinal cord injury in mice.More importantly,in ex vivo,human plasma exosomes(HP-EXO)loaded with combinatory peptides of RVG,ILP and ISP showed safety and no liver and kidney toxicity in the application to nude SCI mice.Combining the efficacy and safety,the AP-EXO-based personalized treatment confers functional recovery after SCI and showed immense promising in biomedical applications in treating SCI.It is helpful to expand the application of combinatory peptides and human plasma derived autologous exosomes in promoting regeneration and recovery upon SCI treatment.

Spastin is required for human immunodeficiency virus-1 efficient replication through cooperation with the endosomal sorting complex required for transport(ESCRT)protein

Human immunodeficiency virus-1(HIV-1)encodes simply 15 proteins and thus depends on multiple host cellular factors for virus reproduction.Spastin,a microtubule severing protein,is an identified HIV-1 dependency factor,but the mechanism regulating HIV-1 is unclear.Here,the study showed that knockdown of spastin inhibited the production of the intracellular HIV-1 Gag protein and new virions through enhancing Gag lysosomal degradation.Further investigation showed that increased sodium tolerance 1(IST1),the subunit of endosomal sorting complex required for transport(ESCRT),could interact with the MIT domain of spastin to regulate the intracellular Gag production.In summary,spastin is required for HIV-1 replication,while spastin-IST1 interaction facilitates virus production by regulating HIV-1 Gag intracellular trafficking and degradation.Spastin may serve as new target for HIV-1 prophylactic and therapy.

HIV-1 Protein Tat_(1–72) Impairs Neuronal Dendrites via Activation of PP1 and Regulation of the CREB/BDNF Pathway

Despite the success of combined antiretroviral therapy in recent years, the prevalence of human immunodeficiency virus(HIV)-associated neurocognitive disorders in people living with HIV-1 is increasing, significantly reducing the healthrelated quality of their lives. Although neurons cannot be infected by HIV-1, shed viral proteins such as transactivator of transcription(Tat) can cause dendritic damage. However, the detailed molecular mechanism of Tat-induced neuronal impairment remains unknown. In this study, we first showed that recombinant Tat(1–72 aa) induced neurotoxicity in primary cultured mouse neurons. Second, exposure to Tat_(1–72) was shown to reduce the length and number of dendrites in cultured neurons. Third, Tat_(1–72)(0–6 h) modulates protein phosphatase 1(PP1) expression and enhances its activity by decreasing the phosphorylation level of PP1 at Thr320. Finally, Tat_(1–72)(24 h) downregulates CREB activity and CREBmediated gene(BDNF, c-fos, Egr-1) expression. Together, these findings suggest that Tat_(1–72) might impair cognitive function by regulating the activity of PP1 and the CREB/BDNF pathway.

Host protein atlastin-1 promotes human immunodeficiency virus(HIV-1)replication

Here we explored the contribution of atlastin- 1 （ATL 1）to HIV replication for the first time. HIV-1 encodes only15 proteins （Ayinde et al., 2010） and thus must exploitmultiple host cell functions for successful infection. Forexample, HIV-1 envelope （Env） glycoproteins are synthe-sized as a polyprotein precursor, known as gp 160, in theendoplasmic reticulum （ER） （Checkley et al., 2011） 。

Stability of HIV-1 subtype B and C Tat is associated with variation in the carboxyl-terminal region

The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.