The DISABLED protein functions in CLATHRIN-mediated synaptic vesicle endocytosis and exoendocytic coupling at the active zone.

Members of the DISABLED (DAB) family of proteins are known to play a conserved role in endocytic trafficking of cell surface receptors by functioning as monomeric CLATHRIN-associated sorting proteins that recruit cargo proteins into endocytic vesicles. Here, we report a Drosophila disabled mutant revealing a novel role for DAB proteins in chemical synaptic transmission. This mutant exhibits impaired synaptic function, including a rapid activity-dependent reduction in neurotransmitter release and disruption of synaptic vesicle endocytosis. In presynaptic boutons, Drosophila DAB and CLATHRIN were highly colocalized within two distinct classes of puncta, including relatively dim puncta that were located at active zones and may reflect endocytic mechanisms operating at neurotransmitter release sites. Finally, broader analysis of endocytic proteins, including DYNAMIN, supported a general role for CLATHRIN-mediated endocytic mechanisms in rapid clearance of neurotransmitter release sites for subsequent vesicle priming and refilling of the release-ready vesicle pool.

Clinical Effect of Minimally Invasive Percutaneous Pedicle Screw Internal Fixation Combined with Injured Vertebrae Bone Grafting in the Treatment of Thoracolumbar Fractures in Orthopedic Surgery.

Objective: To observe the clinical effect of minimally invasive percutaneous pedicle screw internal fixation combined with injured vertebrae bone grafting in the treatment of thoracolumbar fractures in orthopedic surgery. Methods: A total of 132 patients with thoracolumbar fractures admitted to the hospital were enrolled between January 2020 and April 2021. Both groups underwent minimally invasive percutaneous pedicle screw internal fixation. According to the presence or absence of intraoperative injured vertebrae bone grafting, they were divided into the grafting group (73 cases) and the injured vertebrae ungrafted group (59 cases). The perioperative indexes, pain at 2 weeks after surgery, surgical stress, recovery of an injured vertebra, self-care ability, quality of life, and postoperative complications were compared between the two groups. Result: There was no significant difference in intraoperative blood loss, operation time, or hospitalization time between the grafting group and the nongrafting group (P > 0.05).2 weeks after surgery, scores of the Visual Analogue Scale (VAS) in the grafting group were lower than those in the nongrafting group (P < 0.05).At 3d after surgery, levels of serum cortisol (COR), epinephrine (E), and norepinephrine (NE) in both groups were higher than those before surgery, which were lower in the grafting group than in the nongrafting group (P < 0.05).At 3 months after surgery, the anterior edge height of the injured vertebra in both groups was increased, which was higher in the grafting group than in the nongrafting group (P < 0.05). At 3 months after surgery, the Cobb angle of sagittal kyphosis in both groups was decreased, which was lower in the grafting group than that in the nongrafting group (P < 0.05). At 3 months after surgery, the scores of activity of daily living (ADL) and the MOS item-short form health survey (SF-36) in both groups were higher than those before surgery, which were higher in the grafting group than in the nongrafting group (P < 0.05). The difference in the incidence rate of injured vertebrae collapse, internal fixation breakage, or kyphosis between the grafting group and the nongrafting group was not statistically significant (1.37% vs 6.78%) (P > 0.05). Conclusion: Minimally invasive percutaneous pedicle screw internal fixation combined with injured vertebrae bone grafting in orthopedic surgery can improve postoperative pain and surgical stress in patients with thoracolumbar fractures, which is conducive to the recovery of injured vertebrae and improvement in the quality of life.

The mechanism and significance of deletion of parasite-specific CD4(+) T cells in malaria infection.

It is thought that both helper and effector functions of CD4(+) T cells contribute to protective immunity to blood stage malaria infection. However, malaria infection does not induce long-term immunity and its mechanisms are not defined. In this study, we show that protective parasite-specific CD4(+) T cells were depleted after infection with both lethal and nonlethal species of rodent PLASMODIUM: It is further shown that the depletion is confined to parasite-specific T cells because (a) ovalbumin (OVA)-specific CD4(+) T cells are not depleted after either malaria infection or direct OVA antigen challenge, and (b) the depletion of parasite-specific T cells during infection does not kill bystander OVA-specific T cells. A significant consequence of the depletion of malaria parasite-specific CD4(+) T cells is impaired immunity, demonstrated in mice that were less able to control parasitemia after depletion of transferred parasite-specific T cells. Using tumor necrosis factor (TNF)-RI knockout- and Fas-deficient mice, we demonstrate that the depletion of parasite-specific CD4(+) T cells is not via TNF or Fas pathways. However, in vivo administration of anti-interferon (IFN)-gamma antibody blocks depletion, suggesting that IFN-gamma is involved in the process. Taken together, these data suggest that long-term immunity to malaria infection may be affected by an IFN-gamma-mediated depletion of parasite-specific CD4(+) T cells during infection. This study provides further insight into the nature of immunity to malaria and may have a significant impact on approaches taken to develop a malaria vaccine.

MAP1 structural organization in Drosophila: in vivo analysis of FUTSCH reveals heavy- and light-chain subunits generated by proteolytic processing at a conserved cleavage site.

The MAP1 (microtubule-associated protein 1) family is a class of microtubule-binding proteins represented by mammalian MAP1A, MAP1B and the recently identified MAP1S. MAP1A and MAP1B are expressed in the nervous system and thought to mediate interactions of the microtubule-based cytoskeleton in neural development and function. The characteristic structural organization of mammalian MAP1s, which are composed of heavy- and light-chain subunits, requires proteolytic cleavage of a precursor polypeptide encoded by the corresponding map1 gene. MAP1 function in Drosophila appears to be fulfilled by a single gene, futsch. Although the futsch gene product is known to share several important functional properties with mammalian MAP1s, whether it adopts the same basic structural organization has not been addressed. Here, we report the identification of a Drosophila MAP1 light chain, LC(f), produced by proteolytic cleavage of a futsch-encoded precursor polypeptide, and confirm co-localization and co-assembly of the heavy chain and LC(f) cleavage products. Furthermore, the in vivo properties of MAP1 proteins were further defined through precise MS identification of a conserved proteolytic cleavage site within the futsch-encoded MAP1 precursor and demonstration of light-chain diversity represented by multiple LC(f) variants. Taken together, these findings establish conservation of proteolytic processing and structural organization among mammalian and Drosophila MAP1 proteins and are expected to enhance genetic analysis of conserved MAP1 functions within the neuronal cytoskeleton.

Preclinical evaluation of a vaccine based on conserved region of M protein that prevents group A streptococcal infection.

BACKGROUND & OBJECTIVES: Infection with group A Streptococcus (GAS) may result in a number of human diseases ranging from the relatively benign pharyngitis to the potentially life-threatening invasive diseases and post-infectious sequelae. We have previously defined a minimal B-cell epitope from the conserved region of the M-protein. Here we report on the immunogenicity, opsonic potential of the resulting sera and the level of protection induced by this peptide in comparison to a pepsin extract of the M protein. METHODS: Inbred mice were immunized with peptides derived from the M protein. Sera were collected from the immunized mice and its opsonic potential determined for M1 and M6 GAS strains. Mice were then intranasally challenged with a virulent M1 GAS strain to determine the protective efficacy of the peptides. RESULTS: The peptides induced significant antibody responses when delivered subcutaneously and immunized mice demonstrated significantly enhanced survival compared to control groups following challenge. INTERPRETATION & CONCLUSION: The data obtained in the present study indicated that the chimeric peptide J8 from the conserved region of the M protein could form the basis for an anti-streptococcal vaccine in future.

Toward the development of an antidisease, transmission-blocking intranasal vaccine for group a streptococcus.

Infection with group A streptococcus (GAS) may result in a number of clinical conditions, including the potentially life-threatening postinfectious sequelae of rheumatic fever and rheumatic heart disease. As part of the search for a vaccine to prevent GAS infection, a conformationally constrained and minimally conserved peptide, J14, from the M protein of GAS has been defined. In the present study, J14 was formulated with bacterial outer membrane proteins (proteosomes) and then intranasally administered to outbred mice without additional adjuvant. Such immunization led to high titers of J14-specific serum immunoglobulin (Ig) G and mucosal IgA. After upper respiratory tract GAS challenge, immunized mice demonstrated increased survival and reduced GAS colonization of the throat.