Structure of the FKBP12-rapamycin complex interacting with the binding domain of human FRAP

Rapamycin, a potent immunosuppressive agent, binds two proteins: the FK506-binding protein (FKBP12) and the FKBP-rapamycin-associated protein (FRAP). A crystal structure of the ternary complex of human FKBP12, rapamycin, and the FKBP12-rapamycin-binding (FRB) domain of human FRAP at a resolution of 2.7 angstroms revealed the two proteins bound together as a result of the ability of rapamycin to occupy two different hydrophobic binding pockets simultaneously. The structure shows extensive interactions between rapamycin and both proteins, but fewer interactions between the proteins. The structure of the FRB domain of FRAP clarifies both rapamycin-independent and -dependent effects observed for mutants of FRAP and its homologs in the family of proteins related to the ataxia-telangiectasia mutant gene product, and it illustrates how a small cell-permeable molecule can mediate protein dimerization.

Haplotype variation and linkage disequilibrium in 313 human genes

Variation within genes has important implications for all biological traits. We identified 3899 single nucleotide polymorphisms (SNPs) that were present within 313 genes from 82 unrelated individuals of diverse ancestry, and we organized the SNPs into 4304 different haplotypes. Each gene had several variable SNPs and haplotypes that were present in all populations, as well as a number that were population-specific. Pairs of SNPs exhibited variability in the degree of linkage disequilibrium that was a function of their location within a gene, distance from each other, population distribution, and population frequency. Haplotypes generally had more information content (heterozygosity) than did individual SNPs. Our analysis of the pattern of variation strongly supports the recent expansion of the human population.

Obesity and C-reactive protein in various populations: a systematic review and meta-analysis

Obesity has been associated with elevated levels of C-reactive protein (CRP), a marker of inflammation and predictor of cardiovascular risk. The objective of this systematic review and meta-analysis was to estimate the associations between obesity and CRP according to sex, ethnicity and age. MEDLINE and EMBASE databases were searched through October 2011. Data from 51 cross-sectional studies that used body mass index (BMI), waist circumference (WC) or waist-to-hip ratio (WHR) as measure of obesity were independently extracted by two reviewers and aggregated using random-effects models. The Pearson correlation (r) for BMI and ln(CRP) was 0.36 (95% confidence interval [CI], 0.30-0.42) in adults and 0.37 (CI, 0.31-0.43) in children. In adults, r for BMI and ln(CRP) was greater in women than men by 0.24 (CI, 0.09-0.37), and greater in North Americans/Europeans than Asians by 0.15 (CI, 0-0.28), on average. In North American/European children, the sex difference in r for BMI and ln(CRP) was 0.01 (CI, -0.08 to 0.06). Although limited to anthropometric measures, we found similar results when WC and WHR were used in the analyses. Obesity is associated with elevated levels of CRP and the association is stronger in women and North Americans/Europeans. The sex difference only emerges in adulthood.

Organic/inorganic hybrid composites from cubic silsesquioxanes

A new class of epoxy nanocomposites with completely defined organic/inorganic phases was prepared by reacting octakis(glycidyldimethylsiloxy)octasilsesquioxane [(glydicylMe(2)SiOSiO(1.5))(8)] (OG) with diaminodiphenylmethane (DDM) at various compositional ratios. The effects of reaction curing conditions on nanostructural organization and mechanical properties were explored. A commercial epoxy resin based on the diglycidyl ether of bisphenol A (DGEBA) was used as a reference material throughout these studies. FTIR was used to follow the curing process and to demonstrate that the silsesquioxane structure is preserved during processing. OG/DDM composites possess comparable tensile moduli (E) and fracture toughness (K(IC)) to, and better thermal stabilities than, DGEBA/DDM cured under similar conditions. Dynamic mechanical analysis and model reaction studies suggest that the maximum cross-link density is obtained at N = 0.5 (NH(2):epoxy groups = 0.5) whereas the mechanical properties are maximized at N = 1.0. Digestion of the inorganic core with HF followed by GPC analysis of the resulting organic tether fragments when combined with the model reaction studies confirms that, at N = 0.5, each organic tether connects four cubes, while, at N = 1.0, linear tethers connecting two cubes dominate the network structure. Thus, well-defined nanocomposites with controlled variation of the organic tether architecture can be made and their properties assessed.

MyoD converts primary dermal fibroblasts, chondroblasts, smooth muscle, and retinal pigmented epithelial cells into striated mononucleated myoblasts and multinucleated myotubes

Shortly after their birth, postmitotic mononucleated myoblasts in myotomes, limb buds, and conventional muscle cultures elongate and assemble a cohort of myofibrillar proteins into definitively striated myofibrils. MyoD induces a number of immortalized and/or transformed nonmuscle cells to express desmin and several myofibrillar proteins and to fuse into myosacs. We now report that MyoD converts normal dermal fibroblasts, chondroblasts, gizzard smooth muscle, and pigmented retinal epithelial cells into elongated postmitotic mononucleated striated myoblasts. The sarcomeric localization of antibodies to desmin, alpha-actinin, titin, troponin-I, alpha-actin, myosin heavy chain, and myomesin in these converted myoblasts are indistinguishable from in vivo and in vitro normal myoblasts. Converted myoblasts fuse into typical anisodiametric multinucleated myotubes that often contract spontaneously. Conversion and subsequent expression of the skeletal myogenic program are autonomous events, occurring in four nonmuscle microenvironments consisting of different combinations of foreign extracellular matrix molecules. Early events associated with conversion by MyoD involve (i) withdrawal from the cell cycle, (ii) down-regulation of the subverted cell's ongoing differentiation program, and (iii) initiation of desmin synthesis in presumptive myoblasts and dramatic redistribution of microtubules and desmin intermediate filaments in postmitotic myoblasts.

Quantal puffs of intracellular Ca2+ evoked by inositol trisphosphate in Xenopus oocytes

1. Ca2+ liberation induced in Xenopus oocytes by a poorly metabolized derivative of inositol 1,4,5-trisphosphate (3-deoxy-3-fluoro-D-myo-inositol 1,4,5-trisphosphate; 3-F-InsP3) was visualized using a video-rate confocal microscope to image fluorescence signals reported by the indicator dye calcium green-1. 2. Low (10-30 nM) intracellular concentrations of 3-F-InsP3 evoked Ca2+ release as localized transient 'puffs'. Progressively higher concentrations (30-60 nM) gave rise to abortive Ca2+ waves triggered by puffs, and then (> 60 nM) to a sustained elevation of Ca2+ followed by the appearance of propagating Ca2+ waves. At concentrations up to that giving waves, the frequency of puffs increased as about the third power of [InsP3], whereas their amplitudes increased only slightly. 3. The rise of cytosolic Ca2+ during a puff began abruptly, and peaked within about 50 ms. The peak free Ca2+ level was about 180 nM, and the total amount of Ca2+ liberated was several attomoles (10(-18) mol), too much to be accounted for by opening of a single InsP3-gated channel. The subsequent decline of Ca2+ occurred over a few hundred milliseconds, determined largely by diffusion of Ca2+ away from the release site, rather than by resequestration. Lateral spread of Ca2+ was restricted to a few micrometres, consistent with an effective diffusion coefficient for Ca2+ ions of about 27 microns2 s-1. 4. The peak amplitudes of puffs recorded at a given site were distributed in a roughly Gaussian manner, and a small proportion of sites consistently gave puffs much larger than the main population. Intervals between successive puffs at a single site were exponentially distributed, except for a progressive fall-off in puffs seen at intervals shorter than about 10 s. Thus, triggering of puffs appeared to be stochastically determined after recovery from a refractory period. 5. There was little correlation between the occurrence of puffs at sites more than a few micrometres apart, indicating that puff sites can function autonomously, but closely (ca 2 microns) adjacent sites showed highly correlated behaviour. 6. Puffs arose from sites-present at a density of about 1 per 30 microns2 in the animal hemisphere, located within a narrow band about 5-7 microns below the plasma membrane. 7. We conclude that Ca2+ puffs represent a 'quantal' unit of InsP3-evoked Ca2+ liberation, which may arise because local regenerative feedback by cytosolic Ca2+ ions causes the concerted opening of several closely clustered InsP3 receptor channels.

EGFR mutation subtypes and response to immune checkpoint blockade treatment in non-small-cell lung cancer

BACKGROUND

Although EGFR mutant tumors exhibit low response rates to immune checkpoint blockade overall, some EGFR mutant tumors do respond to these therapies; however, there is a lack of understanding of the characteristics of EGFR mutant lung tumors responsive to immune checkpoint blockade.

PATIENTS AND METHODS

We retrospectively analyzed de-identified clinical and molecular data on 171 cases of EGFR mutant lung tumors treated with immune checkpoint inhibitors from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, University of California Los Angeles, and Dana Farber Cancer Institute. A separate cohort of 383 EGFR mutant lung cancer cases with sequencing data available from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, and The Cancer Genome Atlas was compiled to assess the relationship between tumor mutation burden and specific EGFR alterations.

RESULTS

Compared with 212 EGFR wild-type lung cancers, outcomes with programmed cell death 1 or programmed death-ligand 1 (PD-(L)1) blockade were worse in patients with lung tumors harboring alterations in exon 19 of EGFR (EGFRΔ19) but similar for EGFRL858R lung tumors. EGFRT790M status and PD-L1 expression did not impact response or survival outcomes to immune checkpoint blockade. PD-L1 expression was similar across EGFR alleles. Lung tumors with EGFRΔ19 alterations harbored a lower tumor mutation burden compared with EGFRL858R lung tumors despite similar smoking history.

CONCLUSIONS

EGFR mutant tumors have generally low response to immune checkpoint inhibitors, but outcomes vary by allele. Understanding the heterogeneity of EGFR mutant tumors may be informative for establishing the benefits and uses of PD-(L)1 therapies for patients with this disease.

Assessment of Tocilizumab (Anti-Interleukin-6 Receptor Monoclonal) as a Potential Treatment for Chronic Antibody-Mediated Rejection and Transplant Glomerulopathy in HLA-Sensitized Renal Allograft Recipients

Extending the functional integrity of renal allografts is the primary goal of transplant medicine. The development of donor-specific antibodies (DSAs) posttransplantation leads to chronic active antibody-mediated rejection (cAMR) and transplant glomerulopathy (TG), resulting in the majority of graft losses that occur in the United States. This reduces the quality and length of life for patients and increases cost. There are no approved treatments for cAMR. Evidence suggests the proinflammatory cytokine interleukin 6 (IL-6) may play an important role in DSA generation and cAMR. We identified 36 renal transplant patients with cAMR plus DSAs and TG who failed standard of care treatment with IVIg plus rituximab with or without plasma exchange. Patients were offered rescue therapy with the anti-IL-6 receptor monoclonal tocilizumab with monthly infusions and monitored for DSAs and long-term outcomes. Tocilizumab-treated patients demonstrated graft survival and patient survival rates of 80% and 91% at 6 years, respectively. Significant reductions in DSAs and stabilization of renal function were seen at 2 years. No significant adverse events or severe adverse events were seen. Tocilizumab provides good long-term outcomes for patients with cAMR and TG, especially compared with historical published treatments. Inhibition of the IL-6-IL-6 receptor pathway may represent a novel approach to stabilize allograft function and extend patient lives.

Elementary events of InsP3-induced Ca2+ liberation in Xenopus oocytes: hot spots, puffs and blips

Liberation of sequestered Ca2+ ions in Xenopus oocytes by the second messenger inositol 1,4,5-trisphosphate (InP3) occurs from functionally discrete sites, which are spaced at intervals of several microns and probably represent clusterings of InsP3 receptor/channels (InsP3R) in the endoplasmic reticulum. As well as requiring InsP3, opening of release channels is regulated by dual positive and negative feedback by cytosolic Ca2+, leading to regenerative Ca2+ transients. Because the sensitivity of this process is determined by [InsP3], the ability of Ca2+ ions diffusing from one location to activate increasingly distant InsP3R is enhanced by increasing [InsP3]. Together with the spatial distribution of receptors, this results in generation of a hierarchy of Ca2+ release events, which may involve individual InsP3R (Ca2+ 'blips'), concerted activation of several receptors within a single release site (Ca2+ 'puffs'), and recruitment of successive sites by Ca2+ diffusing over micron distances to produce propagating Ca2+ waves. Thus, Ca2+ signalling in the oocyte is organized as at least two sizes of elemental 'building blocks'; highly localized Ca2+ transients that arise autonomously and stochastically from discrete sites at low [InsP3], but which become coordinated at higher [InsP3] to produce global Ca2+ responses.

Learning upregulates brain-derived neurotrophic factor messenger ribonucleic acid: a mechanism to facilitate encoding and circuit maintenance?

Brain-derived neurotrophic factor (BDNF) promotes neuron survival, enhances sprouting, protects neurons against insult, and may be involved in several aspects of learning and memory. In this study, rats trained to locate a submerged platform in a water maze had elevated levels of BDNF messenger ribonucleic acid (mRNA) in the hippocampus (p < .05), a structure associated with spatial memory. BDNF mRNA expression increased after 3 and 6 days but not after 1 day of training in the water maze. A yoked control group that swam without the platform present, to control for physical activity, showed a trend for elevated BDNF mRNA at an intermediate level between the learning and sedentary groups. Other cortical and subcortical areas did not show a significant increase in BDNF mRNA after learning or activity (p > .05). These findings suggest that learning can impact BDNF mRNA expression localized to the brain areas involved in the processing of spatial information. Furthermore, behaviors such as physical activity and learning may help maintain and protect neurons at risk in aging and neurodegenerative disease via increased BDNF expression.

Purification and characterization of a fibrinolytic enzyme produced from Bacillus sp. strain CK 11-4 screened from Chungkook-Jang

Bacillus sp. strain CK 11-4, which produces a strongly fibrinolytic enzyme, was screened from Chungkook-Jang, a traditional Korean fermented-soybean sauce. The fibrinolytic enzyme (CK) was purified from supernatant of Bacillus sp. strain CK 11-4 culture broth and showed thermophilic, hydrophilic, and strong fibrinolytic activity. The optimum temperature and pH were 70 degrees C and 10.5, respectively, and the molecular weight was 28,200 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first 14 amino acids of the N-terminal sequence of CK are Ala-Gin-Thr-Val-Pro-Tyr-Gly-Ile-Pro-Leu-Ile-Lys-Ala-Asp. This sequence is identical to that of subtilisin Carlsberg and different from that of nattokinase, but CK showed a level of fibrinolytic activity that was about eight times higher than that of subtilisin Carlsberg. The amidolytic activity of CK increased about twofold at the initial state of the reaction when CK enzyme was added to a mixture of plasminogen and substrate (H-D-Val-Leu-Lys-pNA). A similar result was also obtained from fibrin plate analysis.

Deep venous thrombosis: detection by using indirect CT venography. The Pulmonary Angiography-Indirect CT Venography Cooperative Group

PURPOSE

To assess the clinical benefits of performing indirect computed tomographic (CT) venography after pulmonary CT angiography to detect deep venous thrombosis (DVT) in patients suspected of having a pulmonary embolism.

MATERIALS AND METHODS

The authors prospectively enrolled 541 consecutive patients who underwent pulmonary CT angiography for suspected pulmonary embolism at seven institutions. Using a protocol that optimizes venous enhancement without additional contrast material injection, the authors obtained contiguous images from the pelvis to the popliteal fossa. Ultrasonography (US) also was performed in 116 patients.

RESULTS

DVT was found at indirect CT venography in 45 (8%), and pulmonary embolism was found at pulmonary CT angiography in 91 (17%) of 541 patients. Among the 45 patients with DVT, DVT occurred in 16 patients who had no pulmonary embolism at pulmonary CT angiography, which increased the diagnosis of thromboembolic disease by 18%. Among 116 patients who underwent US and indirect CT venography, 15 had DVT at US, and in all 15, DVT also was seen at indirect CT venography. In four additional cases, DVT was seen at only indirect CT venography.

CONCLUSION

Among patients suspected to have pulmonary embolism, a substantial number had DVT in the absence of pulmonary embolism. Combined pulmonary CT angiography-indirect CT venography can depict these cases with accuracy comparable to that of US and thus could have a significant effect on patient care.

Ethanol-induced neuronal apoptosis in vivo requires BAX in the developing mouse brain

A single episode of ethanol intoxication triggers widespread apoptotic neurodegeneration in the infant rat or mouse brain. The cell death process occurs over a 6-16 h period following ethanol administration, is accompanied by a robust display of caspase-3 enzyme activation, and meets ultrastructural criteria for apoptosis. Two apoptotic pathways (intrinsic and extrinsic) have been described, either of which may culminate in the activation of caspase-3. The intrinsic pathway is regulated by Bax and Bcl-XL and involves Bax-induced mitochondrial dysfunction and release of cytochrome c as antecedent events leading to caspase-3 activation. Activation of caspase-8 is a key event preceding caspase-3 activation in the extrinsic pathway. In the present study, following ethanol administration to infant mice, we found no change in activated caspase-8, which suggests that the extrinsic pathway is not involved in ethanol-induced apoptosis. We also found that ethanol triggers robust caspase-3 activation and apoptotic neurodegeneration in C57BL/6 wildtype mice, but induces neither phenomenon in homozygous Bax-deficient mice. Therefore, it appears that ethanol-induced neuroapoptosis is an intrinsic pathway-mediated phenomenon involving Bax-induced disruption of mitochondrial membranes and cytochrome c release as early events leading to caspase-3 activation.

Differential protein stability and clinical responses of EML4-ALK fusion variants to various ALK inhibitors in advanced ALK-rearranged non-small cell lung cancer

Background

Anaplastic lymphoma kinase (ALK) inhibition using crizotinib has become the standard of care in advanced ALK-rearranged non-small cell lung cancer (NSCLC), but the treatment outcomes and duration of response vary widely. Echinoderm microtubule-associated protein-like 4 (EML4)-ALK is the most common translocation, and the fusion variants show different sensitivity to crizotinib in vitro. However, there are only limited data on the specific EML4-ALK variants and clinical responses of patients to various ALK inhibitors.

Patients and methods

By multiplex reverse-transcriptase PCR, which detects 12 variants of known EML4-ALK rearrangements, we retrospectively determined ALK fusion variants in 54 advanced ALK rearrangement-positive NSCLCs. We subdivided the patients into two groups (variants 1/2/others and variants 3a/b) by protein stability and evaluated correlations of the variant status with clinical responses to crizotinib, alectinib, or ceritinib. Moreover, we established the EML4-ALK variant-expressing system and analyzed patterns of sensitivity of the variants to ALK inhibitors.

Results

Of the 54 tumors analyzed, EML4-ALK variants 3a/b (44.4%) was the most common type, followed by variants 1 (33.3%) and 2 (11.1%). The 2-year progression-free survival (PFS) rate was 76.0% [95% confidence interval (CI) 56.8-100] in group EML4-ALK variants 1/2/others versus 26.4% (95% CI 10.5-66.6) in group variants 3a/b (P = 0.034) among crizotinib-treated patients. Meanwhile, the 2-year PFS rate was 69.0% (95% CI 49.9-95.4) in group variants 1/2/others versus 32.7% (95% CI 15.6-68.4) in group variants 3a/b (P = 0.108) among all crizotinib-, alectinib-, and ceritinib-treated patients. Variant 3a- or 5a-harboring cells were resistant to ALK inhibitors with >10-fold higher half maximal inhibitory concentration in vitro.

Conclusion

Our findings show that group EML4-ALK variants 3a/b may be a major source of ALK inhibitor resistance in the clinic. The variant-specific genotype of the EML4-ALK fusion allows for more precise stratification of patients with advanced NSCLC.

Clinical Characteristics and Treatment of Immune-Related Adverse Events of Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have been changing the paradigm of cancer treatment. However, immune-related adverse effects (irAEs) have also increased with the exponential increase in the use of ICIs. ICIs can break up the immunologic homeostasis and reduce T-cell tolerance. Therefore, inhibition of immune checkpoint can lead to the activation of autoreactive T-cells, resulting in various irAEs similar to autoimmune diseases. Gastrointestinal toxicity, endocrine toxicity, and dermatologic toxicity are common side effects. Neurotoxicity, cardiotoxicity, and pulmonary toxicity are relatively rare but can be fatal. ICI-related gastrointestinal toxicity, dermatologic toxicity, and hypophysitis are more common with anti- CTLA-4 agents. ICI-related pulmonary toxicity, thyroid dysfunction, and myasthenia gravis are more common with PD-1/PD-L1 inhibitors. Treatment with systemic steroids is the principal strategy against irAEs. The use of immune-modulatory agents should be considered in case of no response to the steroid therapy. Treatment under the supervision of multidisciplinary specialists is also essential, because the symptoms and treatments of irAEs could involve many organs. Thus, this review focuses on the mechanism, clinical presentation, incidence, and treatment of various irAEs.

Comparison of endoscopic ultrasonography and conventional endoscopy for prediction of depth of tumor invasion in early gastric cancer

BACKGROUND AND STUDY AIMS

This study aimed to compare the diagnostic accuracy of endoscopic ultrasonography (EUS) with that of conventional endoscopy for staging depth of invasion (T staging) in early gastric cancer.

PATIENTS AND METHODS

A total of 955 patients with suspected early gastric cancer were prospectively registered. EUS staging was carried out prospectively by a single endoscopist using either miniprobe or radial EUS depending on the endoscopic appearance of the tumor. Conventional endoscopy staging was performed retrospectively by consensus between two endoscopists who were blinded to the EUS staging. Conventional endoscopy staging was conducted on the basis of endoscopic features such as surface nodularity and fold convergence. Patients underwent either surgical (n = 586) or endoscopic resection (n = 369) with curative intent. The staging accuracy of each test was compared with the pathological staging of the resected specimen.

RESULTS

The presence of a T1m tumor was histologically confirmed in 644 cases (67.4 %) and that of a T1sm tumor in 311 cases (32.6 %). The overall accuracy of EUS staging was 67.4 % (644 / 955) and that of conventional endoscopy staging was 73.7 % (704 / 955) ( P < 0.001). The accuracy of miniprobe EUS was significantly higher than that of radial EUS (79.5 % vs. 59.6 %, P < 0.001), but did not differ significantly from that of conventional endoscopy (79.0 %).

CONCLUSIONS

EUS does not substantially impact on pretreatment T staging of patients with early gastric cancer compared with conventional endoscopy. Therefore, EUS may not be necessary routinely, and conventional endoscopy may be sufficient for determining the optimal therapeutic strategy, especially in relation to endoscopic resection for early gastric cancer.

DNA elimination in Tetrahymena: a developmental process involving extensive breakage and rejoining of DNA at defined sites

Elimination of specific DNA sequences occurs during macronuclear development in the ciliate Tetrahymena thermophila. Recombinant DNA clones containing a segment of micronuclear (germinal) DNA involved in elimination and the corresponding segment of macronuclear (somatic) DNA produced after elimination were isolated. Detailed comparisons of the cloned DNAs, as well as the genomic DNAs, by hybridization indicated that DNA elimination is accompanied by specific DNA rearrangements. In this 9.5 kb region three defined DNA segments are deleted and the remaining sequences are linked together as one contiguous piece in the macronucleus. Specific DNA rearrangement of this kind occurs widely in the genome. Analysis of 20 randomly selected DNA clones suggests that there are more than 5000 such rearrangement sites in the genome. Thus specific breakage and rejoining of DNA occurs extensively during development, and might play an essential role in nuclear differentiation.

Reperfusion differentially induces caspase-3 activation in ischemic core and penumbra after stroke in immature brain

BACKGROUND AND PURPOSE

Different strategies for neuroprotection of neonatal stroke may be required because the developing brain responds differently to hypoxia-ischemia than the mature brain. This study was designed to determine the role of caspase-dependent injury in the pathophysiology of pure focal cerebral ischemia in the immature brain.

METHODS

Postnatal day 7 rats were subjected to permanent or transient middle cerebral artery (MCA) occlusion. Diffusion-weighted MRI was used during occlusion to noninvasively map the evolving ischemic core. The time course of caspase-3 activation in ischemic brain tissue was determined with the use of an Asp-Glu-Val-Asp-aminomethylcoumarin cleavage assay. The anatomy of caspase-3 activation in the ischemic core and penumbra was mapped immunohistochemically with an anti-activated caspase-3 antibody in coronal sections that matched the imaging planes on diffusion-weighted MRI.

RESULTS

A marked increase in caspase-3 activity occurred within 24 hours of reperfusion after transient MCA occlusion. In contrast, caspase-3 activity remained significantly lower within 24 hours of permanent MCA occlusion. Cells with activated caspase-3 were prominent in the penumbra beginning at 3 hours after reperfusion, while a more delayed but marked caspase-3 activation was observed in the ischemic core by 24 hours after reperfusion.

CONCLUSIONS

In the neonate, caspase-3 activation is likely to contribute substantially to cell death not only in the penumbra but also in the core after ischemia with reperfusion. Furthermore, persistent perfusion deficits result in less caspase-3 activation and appear to favor caspase-independent injury.

A dormant TIL phenotype defines non-small cell lung carcinomas sensitive to immune checkpoint blockers

The biological determinants of sensitivity and resistance to immune checkpoint blockers are not completely understood. To elucidate the role of intratumoral T-cells and their association with the tumor genomic landscape, we perform paired whole exome DNA sequencing and multiplexed quantitative immunofluorescence (QIF) in pre-treatment samples from non-small cell lung carcinoma (NSCLC) patients treated with PD-1 axis blockers. QIF is used to simultaneously measure the level of CD3+ tumor infiltrating lymphocytes (TILs), in situ T-cell proliferation (Ki-67 in CD3) and effector capacity (Granzyme-B in CD3). Elevated mutational load, candidate class-I neoantigens or intratumoral CD3 signal are significantly associated with favorable response to therapy. Additionally, a "dormant" TIL signature is associated with survival benefit in patients treated with immune checkpoint blockers characterized by elevated TILs with low activation and proliferation. We further demonstrate that dormant TILs can be reinvigorated upon PD-1 blockade in a patient-derived xenograft model.

Molecular mechanism of decreased glutathione content in human immunodeficiency virus type 1 Tat-transgenic mice

Human immunodeficiency virus (HIV) progressively depletes GSH content in humans. Although the accumulated evidence suggests a role of decreased GSH in the pathogenesis of HIV, significant controversy remains concerning the mechanism of GSH depletion, especially in regard to envisioning appropriate therapeutic strategies to help compensate for such decreased antioxidant capacity. Tat, a transactivator encoded by HIV, is sufficient to cause GSH depletion in vitro and is implicated in AIDS-associated Kaposi's sarcoma and B cell lymphoma. In this study, we report a decrease in GSH biosynthesis with Tat, using HIV-1 Tat transgenic (Tat+) mice. A significant decline in the total intracellular GSH content in liver and erythrocytes of Tat+ mice was accompanied by decreased gamma-glutamylcysteine synthetase regulatory subunit mRNA and protein content, which resulted in an increased sensitivity of gamma-glutamylcysteine synthetase to feedback inhibition by GSH. Further study revealed a significant reduction in the activity of GSH synthetase in liver of Tat+ mice, which was linearly associated with their GSH content. Therefore, Tat appears to decrease GSH in vivo, at least partially, through modulation of GSH biosynthetic enzymes.