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The precise contribution of the cadherin-[beta]-catenin synapse adhesion complex in the functional and structural changes associated with the pre- and postsynaptic terminals remains unclear. Here we report a requirement for endogenous [beta]-catenin in regulating synaptic strength and dendritic spine morphology in cultured hippocampal pyramidal neurons. Ablating [beta]-catenin after the initiation of synaptogenesis in the postsynaptic neuron reduces the amplitude of spontaneous excitatory synaptic responses without a concurrent change in their frequency and synapse density. The normal glutamatergic synaptic response is maintained by post-synaptic [beta]-catenin in a cadherin-dependent manner and requires the C-terminal PDZ-binding motif of [beta]-catenin but not the link to the actin cytoskeleton. In addition, ablating [beta]-catenin in post-synaptic neurons accompanies a block of bidirectional quantal scaling of glutamatergic responses induced by chronic activity manipulation. In older cultures at a time when neurons have abundant dendritic spines, neurons ablated for [beta]-catenin show thin, elongated spines and reduced proportion of mushroom spines without a change in spine density. Collectively, these findings suggest that the cadherin-[beta]-catenin complex is an integral component of synaptic strength regulation and plays a basic role in coupling synapse function and spine morphology. [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors | spine morphology | synapse adhesion proteins | quantal scaling

A simple method was developed for access to molecules that contain both ketone and N-H aziridine functionalities. The compounds have undergone highly selective reduction and carbonyl addition reactions, thus making them versatile precursors to complex amines.

Efforts towards the synthesis and functionalization of aziridines, involved in nitrogen transfer reactions, are highlighted. The electrochemical aziridination of olefins, the acid-catalyzed ring opening of aziridines and the development of transition metal mediated nitrogen allylation, arylation and alkenylation of unprotected aziridines are investigated.

The optogenetic manipulation of light-activated ion-channels/pumps (i.e., opsins) can reversibly activate or suppress neuronal activity with precise temporal control. Therefore, optogenetic techniques hold great potential to establish causal relationships between specific neuronal circuits and their function in freely moving animals. Due to the critical role of the hippocampal CA1 region in memory function, we explored the possibility of targeting an inhibitory opsin, ArchT, to CA1 pyramidal neurons in mice. We established a transgenic mouse line in which tetracycline trans-activator induces ArchT expression. By crossing this line with a CaMKIIα-tTA transgenic line, the delivery of light via an implanted optrode inhibits the activity of excitatory CA1 neurons. We found that light delivery to the hippocampus inhibited the recall of a contextual fear memory. Our results demonstrate that this optogenetic mouse line can be used to investigate the neuronal circuits underlying behavior. [ABSTRACT FROM AUTHOR]

Three new diterpene alkaloids - the hypotaurocyamines, (-)-agelasidines E and F ( 5, 6), and an adeninium salt, agelasine N ( 9) - were isolated from the Caribbean sponge Agelas citrina along with six known natural products: agelasines B-E ( 7, 10- 12), 2-oxo-agelasine B ( 8), and (-)-agelasidine C ( 3). The chemical structures of 5, 6, and 9 were elucidated by NMR spectroscopy and mass spectrometry. This represents the first report of natural products from the sponge A. citrina. Unified assignment of the absolute configurations of the new compounds and known compounds was achieved by chemical correlation, quantitative measurements of molar rotations, and comparative analysis by van't Hoff's principle of optical superposition. (-)-Agelasidine C ( 3) exhibited potent antifungal and modest cytotoxic activity against human chronic lymphocytic leukemia (CLL) cells. [ABSTRACT FROM AUTHOR]

Mindin (spondin-2) is an extracellular matrix protein of unknown structure that is required for efficient T-cell priming by dendritic cells. Additionally, mindin functions as a pattern recognition molecule for initiating innate immune responses. These dual functions are mediated by interactions with integrins and microbial pathogens, respectively. Mindin comprises an N-terminal F-spondin (FS) domain and C-terminal thrombospondin type 1 repeat (TSR). We determined the structure of the FS domain at 1.8-Å resolution. The structure revealed an eight-stranded antiparallel β-sandwich motif resembling that of membrane-targeting C2 domains, including a bound calcium ion. We demonstrated that the FS domain mediates integrin binding and identified the binding site by mutagenesis. The mindin FS domain therefore represents a new integrin ligand. We further showed that mindin recognizes lipopolysaccharide (LPS) through its TSR domain, and obtained evidence that C-mannosylation of the TSR influences LPS binding. Through these dual interactions, the FS and TSR domains of mindin promote activation of both adaptive and innate immune responses. [ABSTRACT FROM AUTHOR]

Background: The switching/sucrose non-fermentable (SWI/SNF) Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A (SMARCA) member 2 and member 4 (SMARCA2/4) are paralogs and act as the key enzymatic subunits in the SWI/SNF complex for chromatin remodeling. However, the role of SMARCA2/4 in DNA damage response remains unclear., Methods: Laser microirradiation assays were performed to examine the key domains of SMARCA2/4 for the relocation of the SWI/SNF complex to DNA lesions. To examine the key factors that mediate the recruitment of SMARCA2/4, the relocation of SMARCA2/4 to DNA lesions was examined in HeLa cells treated with inhibitors of Ataxia-telangiectasia-mutated (ATM), Ataxia telangiectasia and Rad3-related protein (ATR), CREB-binding protein (CBP) and its homologue p300 (p300/CBP), or Poly (ADP-ribose) polymerase (PARP) 1/2 as well as in H2AX-deficient HeLa cells. Moreover, by concomitantly suppressing SMARCA2/4 with the small molecule inhibitor FHD286 or Compound 14, the function of SMARCA2/4 in Radiation sensitive 51 (RAD51) foci formation and homologous recombination repair was examined. Finally, using a colony formation assay, the synergistic effect of PARP inhibitors and SMARCA2/4 inhibitors on the suppression of tumor cell growth was examined., Results: We show that SMARCA2/4 relocate to DNA lesions in response to DNA damage, which requires their ATPase activities. Moreover, these ATPase activities are also required for the relocation of other subunits in the SWI/SNF complex to DNA lesions. Interestingly, the relocation of SMARCA2/4 is independent of γH2AX, ATM, ATR, p300/CBP, or PARP1/2, indicating that it may directly recognize DNA lesions as a DNA damage sensor. Lacking SMARCA2/4 prolongs the retention of γH2AX, Ring Finger Protein 8 (RNF8) and Breast cancer susceptibility gene 1 (BRCA1) at DNA lesions and impairs RAD51-dependent homologous recombination repair. Furthermore, the treatment of an SMARCA2/4 inhibitor sensitizes tumor cells to PARP inhibitor treatment., Conclusions: This study reveals SMARCA2/4 as a DNA damage repair factor for double-strand break repair., Competing Interests: The authors declare no conflict of interest. Duo Wu is from the SynRx Therapeutics., (© 2024 The Author(s). Published by IMR Press.)

Epilepsy is a neurological disorder defined by the presence of seizure activity, manifest both behaviorally and as abnormal activity in neuronal networks. An established model to study the disorder in rodents is the systemic injection of kainic acid, an excitatory neurotoxin that at low doses quickly induces behavioral and electrophysiological seizures. Although the CA3 region of the hippocampus has been suggested to be crucial for kainic acid-induced seizure, because of its strong expression of kainate glutamate receptors and its high degree of recurrent connectivity, the precise role of excitatory transmission in CA3 in the generation of seizure and the accompanying increase in neuronal oscillations remains largely untested. Here we use transgenic mice in which CA3 pyramidal cell synaptic transmission can be inducibly silenced in the adult to demonstrate CA3 excitatory output is required for both the generation of epileptiform oscillatory activity and the progression of behavioral seizures.

Background: Continued assessment of casualty complications, such as infections, enables the development of evidence-based guidelines to mitigate excess morbidity and mortality. We examine the Joint Theater Trauma Registry (JTTR) for infections and potential risk factors, such as transfusions, among Iraq and Afghanistan trauma patients., Methods: JTTR entries from deployment-related injuries with completed records between March 19, 2003, and April 13, 2009, were evaluated using International Classification of Diseases-9 codes for infections defined by anatomic/clinical syndromes and/or type of infecting organisms. Risk factors included mechanisms of injury, patient demographics, Injury Severity Score (ISS), and transfusion, including massive transfusions (≥ 10 units of packed red blood cells)., Results: We reviewed 16,742 patients entries (15,021 from Operation Iraqi Freedom (9,883 battle injuries [BI]) and 1,721 from Operation Enduring Freedom (1,090 BI). A total of 96.6% were men and 77.6% were Army personnel. The majority of BI were due to explosive devices (36.3%). There were 921 patients (5.5%) who had one or more infection codes with only 111 (0.6%) recorded deaths (16 with infections). Infections were commonly gram-negative bacteria (47.6%) involving skin/wound infections (26.7%), and lung infections (14.6%). Risk factors or associations that were most notable in univariate and multivariate analysis were calendar year of trauma, ISS, and pattern of injury., Conclusion: The 5.5% infection rate is consistent with previous military and civilian trauma literature; however, with the limitations of the JTTR, the infection rate is likely an underrepresentation due to inadequate level V and long-term infectious complications data. Combat operational trauma is primarily associated with gram-negative bacteria typically involving infections of wounds or other skin structures and lung infections such as pneumonia. They are commonly linked with higher ISS and injuries to the head, neck, and face.

This protocol describes a method for making and culturing rat hippocampal organotypic slices on membrane inserts. Supplementary videos are included to demonstrate visually the different steps of the procedure. Cultured hippocampal slices has been increasingly used as a model for synaptic studies of the brain as they allow examination of mid to long term manipulations in a preparation where the gross cytoarchitecture of the hippocampus is preserved. Combining techniques such as molecular biology, electrophysiology and immunohistochemistry to study physiological or pathological processes can easily be applied to organotypic slices. The technique described here can be used to make organotypic slices from other parts of the brain, other rodent species and from a range of ages. This protocol can be completed in 3 h.