HIV-1 variants with a single-point mutation in the gp41 pocket region exhibiting different susceptibility to HIV fusion inhibitors with pocket- or membrane-binding domain

AbstractEnfuvirtide (T20), the first FDA-approved peptide HIV fusion/entry inhibitor derived from the HIV-1 gp41 C-terminal heptad-repeat (CHR) domain, is believed to share a target with C34, another well-characterized CHR-peptide, by interacting with the gp41 N-terminal heptad-repeat (NHR) to form six-helix bundle core. However, our previous studies showed that T20 mainly interacts with the N-terminal region of the NHR (N-NHR) and lipid membranes, while C34 mainly binds to the NHR C-terminal pocket region. But so far, no one has shown that C34 can induce drug-resistance mutation in the gp41 pocket region. In this study, we constructed pseudoviruses in which the Ala at the position of 67 in the gp41 pocket region was substituted with Asp, Gly or Ser, respectively, and found that these mutations rendered the viruses highly resistant to C34, but sensitive to T20. The NHR-peptide N36 with mutations of A67 exhibited reduced anti-HIV-1 activity and decreased α-helicity. The stability of six-helix bundle formed by C34 and N36 with A67 mutations was significantly lower than that formed by C34 and N36 with wild-type sequence. The combination of C34 and T20 resulted in potent synergistic anti-HIV-1 effect against the viruses with mutations in either N- or C-terminal region in NHR. These results suggest that C34 with a pocket-binding domain and T20 containing the N-NHR- and membrane-binding domains inhibit HIV-1 fusion by interacting with different target sites and the combinatorial use of C34 and T20 is expected to be effective against HIV-1 variants resistant to HIV fusion inhibitors

Maintaining CD4/CD8 ratio and Th1-CTL subsets of chimeric antigen receptor (CAR)-T cells in serum-free culture conditions

Chimeric antigen receptor (CAR) T cells therapy is a promising strategy that significantly controlled the progress of cancer diseases. CAR-T cells could kill cancer cells through cellular immune response; therefore, CD8+ cytotoxic T cells are critical for CAR-T cell therapy. However, recent papers reported that CD4+ T helper cells were important for the response and maintenance of CAR-T cells in vivo. Here, we developed a serum-free CAR-T cell preparation process that maintained the T cell population and controlled the T cell subsets. The CD4+ and CD8+ T cell population in CAR-T cells were maintained at averagely 59.4 % and 34.6%, and the major T cell subsets were Th1 cells and cytotoxic T lymphocytes (CTLs), implying the potentially high cellular immune response. To verifying whether the prepared CAR-T cells were exhausted, the expression of several immune checkpoint markers was determined. Of interest, only less than 20% of CAR-T cells at endpoint were PD-1+ or CTLA4+, but more than 40% of CAR-T cells at the endpoint were TIM-3+, implying most CAR-T cells were not exhausted. These CAR-T cells produced more than 1 ng/mL of IFN-γ in the response to the antigen. Altogether, CAR-T cells could be prepared in our serum-free process in the controlling of T cell subsets, leading to potential high therapeutic potency. Please click Additional Files below to see the full abstract

In vitro high expansion of chimeric antigen receptor (CAR)-T cells in serum-free process conditions

Manufacturing process is an important and complex factor for preparing chimeric antigen receptor (CAR) T cells for therapy. Although serum was widely applied in the culture or expansion of T cells, the quality of serum could be varied from batch to batch, leading to the variation of T cell expansion and quality. In addition, the safety of pathogens from serum and Chemistry, Manufacturing, and Control (CMC) were required to be considered. To overcome the disadvantages of serum application in T cell culture, serum-free and xeno-free culture conditions were required. We intended to develop a rapid serum-free culture condition for the expansion of immune T cells ex vivo. In our optimized serum-free condition, CAR-T cells could be expanded to about 100-200 times to the initial cell number after 6-day culture and the cell viability of all specimens was above 98%. Of interest, the percentage of CAR+ population in all specimens was increases, and the T cell pollutions could be maintained at averagely about 35-40% of CD8+ T cells and averagely about 50-55% of CD4+ T cells after culture. Taken together, our conditions could be applied in the expansion of CAR-T cells for cell therapy to support the minimum requirement of blood or cell samples from patients and to maintain the T cell population. Please click Additional Files below to see the full abstract

A ribose-functionalized NAD+ with unexpected high activity and selectivity for protein poly-ADP-ribosylation.

Nicotinamide adenine dinucleotide (NAD+)-dependent ADP-ribosylation plays important roles in physiology and pathophysiology. It has been challenging to study this key type of enzymatic post-translational modification in particular for protein poly-ADP-ribosylation (PARylation). Here we explore chemical and chemoenzymatic synthesis of NAD+ analogues with ribose functionalized by terminal alkyne and azido groups. Our results demonstrate that azido substitution at 3'-OH of nicotinamide riboside enables enzymatic synthesis of an NAD+ analogue with high efficiency and yields. Notably, the generated 3'-azido NAD+ exhibits unexpected high activity and specificity for protein PARylation catalyzed by human poly-ADP-ribose polymerase 1 (PARP1) and PARP2. And its derived poly-ADP-ribose polymers show increased resistance to human poly(ADP-ribose) glycohydrolase-mediated degradation. These unique properties lead to enhanced labeling of protein PARylation by 3'-azido NAD+ in the cellular contexts and facilitate direct visualization and labeling of mitochondrial protein PARylation. The 3'-azido NAD+ provides an important tool for studying cellular PARylation

Low titers of measles antibody in mothers whose infants suffered from measles before eligible age for measles vaccination

<p>Abstract</p> <p>Background</p> <p>Resurgence or outbreak of measles recently occurred in both developed and developing countries despite long-standing widespread use of measles vaccine. Measles incidence in China has increased since 2002, particularly in infants and in persons ≥ 15 years of age. It is speculated that infants may acquire fewer measles IgG from their mothers, resulting in the reduced duration of protection during their early months of life. This study aimed to clarify the reason of increased susceptibility to measles in young infants in China. Measles IgG in 24 measles infants ≤ 9 months of age and their vaccinated mothers was quantitatively measured. The mean measles neutralizing titer in the vaccinated mothers and in 13 age-match women with the histories of clinical measles were compared.</p> <p>Results</p> <p>All the mothers were confirmed to be vaccinated successfully by the presence of measles IgG. Six vaccinated mothers were positive for measles IgM and had high concentrations of measles IgG and the neutralizing antibody, indicating underwent natural boosting. The mean measles neutralizing titer in 18 vaccinated mothers without natural boosting were significantly lower than that in 13 age-match women with the histories of clinical measles (1:37 vs 1:182, <it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Our results suggest that infants born to mothers who acquired immunity to measles by vaccination may get a relatively small amount of measles antibody, resulting in loss of the immunity to measles before the vaccination age. Measures to improve the immunity in young infants not eligible for measles vaccination would be critical to interrupt the measles transmission in China.</p

Bcl-2 expression predicts sensitivity to chemotherapy in breast cancer: a systematic review and meta-analysis

BACKGROUND: Numerous studies have yielded inconclusive results regarding the relationship between anti-apoptotic protein Bcl-2 expression and the sensitivity to chemotherapy in the patients with breast cancer. The purpose of the current study was therefore to elaborate their relationship. METHODS, FINDINGS: A total of 23 previously published eligible studies involving 2,467 cases were identified and included in this meta-analysis. Negative Bcl-2 expression was associated with good chemotherapy response in breast cancer patients (total objective response [OR]: risk ratio [RR] = 1.16, 95% confidence interval [CI] = 1.02-1.32, p = 0.026; total complete response [CR]: RR = 1.67, 95% CI = 1.24-2.24, p = 0.001; pathological CR: RR = 1.92, 95% CI = 1.38-2.69, p < 0.001). In further stratified analyses, this association remained for sub-groups of response in neoadjuvant chemotherapy setting, especially pathological CR. Besides, negative Bcl-2 expression was significantly associated with good OR and pathological CR in anthracycline-based chemotherapy subgroup. Furthermore, there were significant links between negative Bcl-2 expression and taxane-based chemotherapy with pathological CR, but not OR. CONCLUSION: The results of the present meta-analysis suggest that Bcl-2 expression is a predictive factor for chemotherapy sensitivity in breast cancer patients. They could also potentially benefit further clinical treatment for breast cancers

A controllable superconducting electromechanical oscillator with a suspended membrane

We fabricate a microscale electromechanical system, in which a suspended superconducting membrane, treated as a mechanical oscillator, capacitively couples to a superconducting microwave resonator. As the microwave driving power increases, nonmonotonic dependence of the resonance frequency of the mechanical oscillator on the driving power has been observed. We also demonstrate the optical switching of the resonance frequency of the mechanical oscillator. Theoretical models for qualitative understanding of our experimental observations are presented. Our experiment may pave the way for the application of a mechanical oscillator with its resonance frequency controlled by the electromagnetic and/or optical fields, such as a microwave-optical interface and a controllable element in a superqubit-mechanical oscillator hybrid system.Comment: 8 pages,4 figure

Surface Tension of Polyurethane Solution and Thermodynamic Model

A new improved polyurethane materials was studied to improve the strength of paper, delay the aging of paper, solve the problem of poor permeability of traditional resins to paper, and meanwhile to provide basic data for industrial design and applications, the surface tension of composite solutions consisting of nano-SiO2-based polyurethane, organosilicon-based polyurethane and epoxy cyclohexane-epichlorohydrin polyurethane dissolved in ethyl acetate had been measured at temperatures ranging from 283.15 K to 308.15 K. The surface tension was fitted with the related equation between surface tension and temperature under normal pressure. The mean relative deviations between the calculated value and the experimental value were derived. The results showed that the model estimation of the surface tension of the composite solution were in good agreement with the experimental data, the paper coated by the polyurethane materials had better mechanical property. Therefore, the prepared polyurethane material has great application prospects in the protection of paper

Chondroitin sulfate proteoglycans regulate the growth, differentiation and migration of multipotent neural precursor cells through the integrin signaling pathway

<p>Abstract</p> <p>Background</p> <p>Neural precursor cells (NPCs) are defined by their ability to proliferate, self-renew, and retain the potential to differentiate into neurons and glia. Deciphering the factors that regulate their behaviors will greatly aid in their use as potential therapeutic agents or targets. Chondroitin sulfate proteoglycans (CSPGs) are prominent components of the extracellular matrix (ECM) in the central nervous system (CNS) and are assumed to play important roles in controlling neuronal differentiation and development.</p> <p>Results</p> <p>In the present study, we demonstrated that CSPGs were constitutively expressed on the NPCs isolated from the E16 rat embryonic brain. When chondroitinase ABC was used to abolish the function of endogenous CSPGs on NPCs, it induced a series of biological responses including the proliferation, differentiation and migration of NPCs, indicating that CSPGs may play a critical role in NPC development and differentiation. Finally, we provided evidence suggesting that integrin signaling pathway may be involved in the effects of CSPGs on NPCs.</p> <p>Conclusion</p> <p>The present study investigating the influence and mechanisms of CSPGs on the differentiation and migration of NPCs should help us to understand the basic biology of NPCs during CNS development and provide new insights into developing new strategies for the treatment of the neurological disorders in the CNS.</p