Leukemias expressing the constitutively activated tyrosine kinases (TKs) BCR-ABL1 and FLT3/ITD activate signaling pathways that increase genomic instability through generation of reactive oxygen species (ROS), DNA double-strand breaks (DSBs) and error-prone repair. The non-homologous end-joining (NHEJ) pathway is a major pathway for DSB repair and is highly aberrant in TK-activated-leukemias; an alternative form of NHEJ (ALT-NHEJ) predominates, evidenced by increased expression of DNA ligase IIIα (LIG3) and poly (ADP-ribose) polymerase (PARP1), increased frequency of large genomic deletions, and repair using DNA sequence microhomologies. This study, for the first time, demonstrates that the TK target c-MYC plays a role in transcriptional activation and subsequent expression of LIG3 and PARP1 and contributes to the increased error-prone repair observed in TK-activated leukemias. c-MYC negatively regulates microRNAs miR-150 and miR-22 which demonstrate an inverse correlation with LIG3 and PARP1 expression in primary and cultured leukemia cells and chronic myelogenous leukemia (CML) human patient samples. Notably, inhibition of c-MYC and overexpression of miR-150 and -22 decreases ALT-NHEJ activity. Thus, BCR-ABL1 or FLT3/ITD induces c-MYC expression leads to genomic instability via augmented expression of ALT-NHEJ repair factors that generate repair errors.

MicroRNAs (miRs) play major roles in normal hematopoietic differentiation and hematopoietic malignancies. In this work, we report that miR-27a, and its coordinately expressed cluster (miR-23a∼miR-27a∼miR-24-2), was down-regulated in acute leukemia cell lines and primary samples compared to hematopoietic stem-progenitor cells (HSPCs). Decreased miR-23a cluster expression in some acute leukemia cell lines was mediated by c-MYC. Replacement of miR-27a in acute leukemia cell lines inhibited cell growth due, at least in part, to increased cellular apoptosis. We identified a member of the anti-apoptotic 14-3-3 family of proteins, which support cell survival by interacting with and negatively regulating pro-apoptotic proteins such as Bax and Bad, as a target of miR-27a. Specifically, miR-27a regulated 14-3-3θ at both the mRNA and protein levels. These data indicate that miR-27a contributes a tumor suppressor-like activity in acute leukemia cells via regulation of apoptosis, and that miR-27a and 14-3-3θ may be potential therapeutic targets.

Timely removal of dying or pathogenic cells by phagocytes is essential to maintaining host homeostasis. Phagocytes execute the clearance process with high fidelity while sparing healthy neighboring cells, and this process is at least partially regulated by the balance of "eat-me" and "don't-eat-me" signals expressed on the surface of host cells. Upon contact, eat-me signals activate "prophagocytic" receptors expressed on the phagocyte membrane and signal to promote phagocytosis. Conversely, don't-eat-me signals engage "anti-phagocytic" receptors to suppress phagocytosis. We review the current knowledge of don't-eat-me signaling in normal physiology and disease contexts where aberrant don't-eat-me signaling contributes to pathology.

Background Aging is often associated with behavioral impairments, but some people age more gracefully than others. Why? One factor that may play a role is individual differences in the distinctiveness of neural representations. Previous research has found that neural activation patterns in visual cortex in response to different visual stimuli are often more similar (i.e., less distinctive) in older vs. young participants, a phenomenon referred to as age-related neural dedifferentiation. Furthermore, older people whose neural representations are less distinctive tend to perform worse on a wide range of behavioral tasks. The Michigan Neural Distinctiveness (MiND) project aims to investigate the scope of neural dedifferentiation (e.g., does it also occur in auditory, motor, and somatosensory cortex?), one potential cause (age-related reductions in the inhibitory neurotransmitter gamma-aminobutyric acid (GABA)), and the behavioral consequences of neural dedifferentiation. This protocol paper describes the study rationale and methods being used in complete detail, but not the results (data collection is currently underway). Methods The MiND project consists of two studies: the main study and a drug study. In the main study, we are recruiting 60 young and 100 older adults to perform behavioral tasks that measure sensory and cognitive function. They also participate in functional MRI (fMRI), MR spectroscopy, and diffusion weighted imaging sessions, providing data on neural distinctiveness and GABA concentrations. In the drug study, we are recruiting 25 young and 25 older adults to compare neural distinctiveness, measured with fMRI, after participants take a placebo or a benzodiazepine (lorazepam) that should increase GABA activity. Discussion By collecting multimodal imaging measures along with extensive behavioral measures from the same subjects, we are linking individual differences in neurochemistry, neural representation, and behavioral performance, rather than focusing solely on group differences between young and old participants. Our findings have the potential to inform new interventions for age-related declines. Trial registration This study was retrospectively registered with the ISRCTN registry on March 4, 2019. The registration number is ISRCTN17266136 .

Purpose: Treatment failure from drug resistance is the primary reason for relapse in acute lymphoblastic leukemia (ALL). Improving outcomes by targeting mechanisms of drug resistance is a potential solution.Patients and Methods: We report results investigating the epigenetic modulators decitabine and vorinostat with vincristine, dexamethasone, mitoxantrone, and PEG-asparaginase for pediatric patients with relapsed or refractory B-cell ALL (B-ALL). Twentythree patients, median age 12 years (range, 1-21) were treated in this trial.Results: The most common grade 3-4 toxicities included hypokalemia (65%), anemia (78%), febrile neutropenia (57%), hypophosphatemia (43%), leukopenia (61%), hyperbilirubinemia (39%), thrombocytopenia (87%), neutropenia (91%), and hypocalcemia (39%). Three subjects experienced dose-limiting toxicities, which included cholestasis, steatosis, and hyperbilirubinemia (n ¼ 1); seizure, somnolence, and delirium (n ¼ 1); and pneumonitis, hypoxia, and hyperbilirubinemia (n ¼ 1). Infectious complications were common with 17 of 23 (74%) subjects experiencing grade ≥3 infections including invasive fungal infections in 35% (8/23). Nine subjects (39%) achieved a complete response (CR þ CR without platelet recovery þ CR without neutrophil recovery) and five had stable disease (22%). Nine (39%) subjects were not evaluable for response, primarily due to treatment-related toxicities. Correlative pharmacodynamics demonstrated potent in vivo modulation of epigenetic marks, and modulation of biologic pathways associated with functional antileukemic effects.Conclusions: Despite encouraging response rates and pharmacodynamics, the combination of decitabine and vorinostat on this intensive chemotherapy backbone was determined not feasible in B-ALL due to the high incidence of significant infectious toxicities. This study is registered at http://www. clinicaltrials.gov as NCT01483690.

Objectives: To use a standardized tool for a multicenter assessment of antibiotic appropriateness in ICUs and identify local antibiotic stewardship improvement opportunities. Design: Pilot point prevalence conducted on October 5, 2016; point prevalence survey conducted on March 1, 2017. Setting: ICUs in 12 U.S. acute care hospitals with median bed size 563. Patients: Receiving antibiotics on participating units on March 1, 2017. Interventions: The Centers for Disease Control and Prevention tool for the Assessment of Appropriateness of Inpatient Antibiotics was made actionable by an expert antibiotic stewardship panel and implemented across hospitals. Data were collected by antibiotic stewardship program personnel at each hospital, deidentified and submitted in aggregate for benchmarking. hospital personnel identified most salient reasons for inappropriate use by category and agent. Measurements and Main Results: Forty-seven ICUs participated. Most hospitals (83%) identified as teaching with median licensed ICU beds of 70. On March 1, 2017, 362 (54%) of 667 ICU patients were on antibiotics (range, 8–81 patients); of these, 112 (31%) were identified as inappropriate and administered greater than 72 hours among all 12 hospitals (range, 9–82%). Prophylactic antibiotic regimens and PICU patients demonstrated a statistically significant risk ratio of 1.76 and 1.90 for inappropriate treatment, respectively. Reasons for inappropriate use included unnecessarily broad spectrum (29%), no infection or nonbacterial syndrome (22%), and duration longer than necessary (21%). Of patients on inappropriate antibiotic therapy in surgical ICUs, a statistically significant risk ratio of 2.59 was calculated for noninfectious or nonbacterial reasons for inappropriate therapy. Conclusions: In this multicenter point prevalence study, 31% of ICU antibiotic regimens were inappropriate; prophylactic regimens were often inappropriate across different ICU types, particularly in surgical ICUs. Engaging intensivists in antibiotic stewardship program efforts is crucial to sustain the efficacy of antibiotics and quality of infectious diseases care in critical care settings. This study underscores the value of standardized assessment tools and benchmarking to be shared with local leaders for targeted antibiotic stewardship program interventions.

1 Background: Aging is often associated with behavioral impairments, but some people age more 2 gracefully than others. Why? One factor that may play a role is individual differences in the 3 distinctiveness of neural representations. Previous research has found that neural activation 4 patterns in visual cortex in response to different visual stimuli are often more similar (i.e., less 5 distinctive) in older vs. young participants, a phenomenon referred to as age-related neural 6 dedifferentiation. Furthermore, older people whose neural representations are less distinctive 7 tend to perform worse on a wide range of behavioral tasks. The Michigan Neural Distinctiveness 8 (MiND) project aims to investigate the scope of neural dedifferentiation (e.g., does it also occur 9 in auditory, motor, and somatosensory cortex?), one potential cause (age-related reductions in 10 the inhibitory neurotransmitter gamma-aminobutyric acid (GABA)), and the behavioral 11 consequences of neural dedifferentiation. This protocol paper describes the study rationale and 12 methods being used in complete detail, but not the results (data collection is currently underway). 13Methods/Design: The MiND project consists of two studies: the main study and a drug study. In 14 the main study, we are recruiting 60 young and 100 older adults to perform behavioral tasks that 15 measure sensory and cognitive function. They also participate in functional MRI (fMRI), MR 16 spectroscopy (MRS), and diffusion weighted imaging (DWI) sessions, providing data on neural 17 distinctiveness and GABA concentrations. In the drug study, we are recruiting 25 young and 25 18 older adults to compare neural distinctiveness, measured with fMRI, after participants take (1) a 19 benzodiazepine (lorazepam) that should increase GABA activity or (2) a placebo. 20 Discussion: By collecting multimodal imaging measures (fMRI, MRS, DWI) along with 21 extensive behavioral measures from the same subjects, we are linking individual differences in 22 neurochemistry, neural representation, and behavioral performance, rather than focusing solely 23 3 on group differences between young and old participants. Our findings have the potential to 24 inform new interventions for age-related declines. 25 Background 29Normal aging is associated with pervasive declines in cognitive, motor, and sensory 30 function, even in the absence of significant disease. Further, both the number of older adults and 31 the proportion of older adults in the population are growing at alarming rates. Consequently, tens 32 of millions of healthy people are already experiencing age-related behavioral impairments, and 33 that number is only going to grow. Nevertheless, there are substantial individual differences in 34 age-related behavioral impairments. Some otherwise healthy people experience significant age-35 related declines, while others do not. What distinguishes those who age gracefully from those 36 who experience significant impairments? The answer to that question could transform efforts to 37 reduce, o...

Aging is associated with widespread alterations in cerebral white matter (WM). Most prior studies of age differences in WM have used diffusion tensor imaging (DTI), but typical DTI metrics (e.g., fractional anisotropy; FA) can reflect multiple neurobiological features, making interpretation challenging. Here, we used fixel-based analysis (FBA) to investigate age-related WM differences observed using DTI in a sample of 45 older and 25 younger healthy adults. Age-related FA differences were widespread but were strongly associated with differences in multi-fiber complexity (CX), suggesting that they reflected differences in crossing fibers in addition to structural differences in individual fiber segments. FBA also revealed a frontolimbic locus of age-related effects and provided insights into distinct microstructural changes underlying them. Specifically, age differences in fiber density were prominent in fornix, bilateral anterior internal capsule, forceps minor, body of the corpus callosum, and corticospinal tract, while age differences in fiber cross section were largest in cingulum bundle and forceps minor. These results provide novel insights into specific structural differences underlying major WM differences associated with aging.