In addition to their role in cellular bioenergetics, mitochondria also initiate common forms of programmed cell death (apoptosis) through the release of proteins such as cytochrome c from the intermembrane and intracristal spaces. The release of these proteins is studied in populations of cells by western blotting mitochondrial and cytoplasmic fractions of cellular extracts, and in single cells by fluorescence microscopy using fluorescent indicators and fusion proteins. However, studying the changes in ultrastructure associated with release of proteins requires the higher resolution provided by transmission electron microscopy. Here, we have used fluorescence microscopy to characterize the state of apoptosis in HeLa cells treated with etoposide followed by electron microscopy and three-dimensional electron microscope tomography of the identical cells to study the sequence of structural changes. We have identified a remodelling of the inner mitochondrial membrane into many separate vesicular matrix compartments that accompanies release of proteins; however, this remodelling is not required for efficient release of cytochrome c. Swelling occurs only late in apoptosis after release of cytochrome c and loss of the mitochondrial membrane potential.

Chondroitin sulfate proteoglycans (CSPGs) represent a major barrier to regenerating axons in the central nervous system (CNS), but the structural diversity of their polysaccharides has hampered efforts to dissect the structure-activity relationships underlying their physiological activity. By taking advantage of our ability to chemically synthesize specific oligosaccharides, we demonstrate that a sugar epitope on CSPGs, chondroitin sulfate-E (CS-E), potently inhibits axon growth. Removal of the CS-E motif significantly attenuates the inhibitory activity of CSPGs on axon growth. Furthermore, CS-E functions as a protein recognition element to engage receptors including the transmembrane protein tyrosine phosphatase PTPσ, thereby triggering downstream pathways that inhibit axon growth. Finally, masking the CS-E motif using a CS-Especific antibody reversed the inhibitory activity of CSPGs and stimulated axon regeneration in vivo. These results demonstrate that a specific sugar epitope within chondroitin sulfate polysaccharides can direct important physiological processes and provide new therapeutic strategies to regenerate axons after CNS injury.

Hyperthermia can be produced by near-infrared laser irradiation of gold nanoparticles present in tumors and thus induce tumor cell killing via a bystander effect. To be clinically relevant, however, several problems still need to be resolved. In particular, selective delivery and physical targeting of gold nanoparticles to tumor cells are necessary to improve therapeutic selectivity. Considerable progress has been made with respect to retargeting adenoviral vectors for cancer gene therapy. We therefore hypothesized that covalent coupling of gold nanoparticles to retargeted adenoviral vectors would allow selective delivery of the nanoparticles to tumor cells, thus feasibilizing hyperthermia and gene therapy as a combinatorial therapeutic approach. For this, sulfo-N-hydroxysuccinimide labeled gold nanoparticles were reacted to adenoviral vectors encoding a luciferase reporter gene driven by the cytomegalovirus promoter (AdCMVLuc). We herein demonstrate that covalent coupling could be achieved, while retaining virus infectivity and ability to retarget tumor-associated antigens. These results indicate the possibility of using adenoviral vectors as carriers for gold nanoparticles.

Mitochondria are integral elements of many nerve terminals. They must be appropriately positioned to regulate microdomains of Ca 2ϩ concentration and metabolic demand, but structures that anchor them in place have not been described. By applying the high resolution of electron tomography (ET) to the study of a central terminal, the calyx of Held, we revealed an elaborate cytoskeletal superstructure that connected a subset of mitochondria to the presynaptic membrane near active zones. This cytoskeletal network extended laterally and was well integrated into the nerve terminal cytoskeleton, which included filamentous linkages among synaptic vesicles. ET revealed novel features of inner membrane for these mitochondria. Crista structure was polarized in that crista junctions, circular openings of the inner membrane under the outer membrane, were aligned with the cytoskeletal superstructure and occurred at higher density in mitochondrial membrane facing the presynaptic membrane. These characteristics represent the first instance where a subcomponent of an organelle is shown to have a specific orientation relative to the polarized structure of a cell. The ratio of cristae to outer membrane surface area is large in these mitochondria relative to other tissues, indicating a high metabolic capacity. These observations suggest general principles for cytoskeletal anchoring of mitochondria in all tissues, reveal potential routes for nonsynaptic communication between presynaptic and postsynaptic partners using this novel cytoskeletal framework, and indicate that crista structure can be specialized for particular functions within cellular microdomains.

The ability to tailor plasma membranes with specific glycans may enable the control of signaling events that are critical for proper development and function. We report a method to modify cell surfaces with specific sulfated chondroitin sulfate (CS) glycosaminoglycans using chemically modified liposomes. Neurons engineered to display CS-E-enriched polysaccharides exhibited increased activation of neurotrophin-mediated signaling pathways and enhanced axonal growth. This approach provides a facile, general route to tailor cell membranes with biologically active glycans and demonstrates the potential to direct important cellular events through cell-surface glycan engineering.

Glycosaminoglycans are sulfated polysaccharides that play important roles in fundamental biological processes, such as cell division, viral invasion, cancer and neuroregeneration. The multivalent presentation of multiple glycosaminoglycan chains on proteoglycan scaffolds may profoundly influence their interactions with proteins and subsequent biological activity. However, the importance of this multivalent architecture remains largely unexplored, and few synthetic mimics exist for probing and manipulating glycosaminoglycan activity. Here, we describe a new class of end-functionalized ring-opening metathesis polymerization (ROMP) polymers that mimic the native-like, multivalent architecture found on chondroitin sulfate (CS) proteoglycans. We demonstrate that these glycopolymers can be readily integrated with microarray and surface plasmon resonance technology platforms, where they retain the ability to interact selectively with proteins. ROMP-based glycopolymers are part of a growing arsenal of chemical tools for probing the functions of glycosaminoglycans and for studying their interactions with proteins.

Study characteristicsFollowing our data search in January 2018, we included 10 trials with a total of 844 participants, which we assessed using the standard Cochrane Review protocol. The trials compared the incidence of hernia development around a stoma between a group having a mesh placement at the time of stoma formation and a control group having a conventional stoma formation without mesh placement. Key resultsWe found that mesh placement around the stoma at the time of stoma formation reduces the incidence of future hernia formation. The participants having a mesh fitted had a similar level of complications as those not having a mesh. Quality of evidenceWe found low-quality evidence favouring the insertion of a mesh into people having a stoma.Prosthetic mesh placement for the prevention of parastomal herniation (Review)

Hemophilia A is an inherited bleeding disorder characterized by deficiency of the coagulation protein factor VIII. Development of clotting factor concentrates has resulted in an excellent prognosis for this historically fatal disease. However, neutralizing antidrug antibodies to factor concentrates can develop, complicating management and worsening the prognosis, and thus creating an unmet need for novel therapies. One such agent is emicizumab, a bispecific monoclonal antibody which mimics the function of factor VIII. Collectively across the HAVEN clinical trial program, the rate of antidrug antibodies with neutralizing potential was 0.75%. Since its licensure, there have been no further reports of such antibodies, despite its use in thousands of patients. In this report, we describe a patient with severe hemophilia A with inhibitors who developed a neutralizing antidrug antibody to emicizumab, for whom we performed extensive testing in the special coagulation laboratory.