Abstract

INTRODUCTION

Primary CNS lymphoma is a rare aggressive hematological malignancy. Current chemotherapy for induction phase is HD-MTX single agent or HD-MTX based combination regimen. We report a rare case whose left and right parietal lymphoma lesions in the brain responded to different induction therapy regimens during the induction phase.

CASE REPORT

A 43-year-old female presented with seizure and her brain MRI showed bilateral parietal brain lesions in January of 2020. Biopsy and work-up revealed primary CNS diffuse large B-cell lymphoma (DLBCL). The patient underwent HD-MTX therapy. Brain MRI showed clear progression of left parietal lymphoma but stable right parietal lymphoma after two cycles of HD-MTX at 8 g/m2. The treatment was switched to a rituximab 750 mg/m2 weekly and temozolomide 150 mg/m2 daily one-week-on and one-week-off regimen. After 8 weeks, her brain MRI showed nearly complete response of her left parietal lymphoma to rituximab/temozolomide but progression of her right parietal lymphoma. She was switched back to HD-MTX and completed total 8 cycles. Her right parietal lymphoma lesion showed complete response to HD-MTX. The patient is doing well and has been off the treatment over the past 10 months and is waiting for consolidation therapy with autologous stem cell transplantation that has been postponed due to the COVID pandemic.

DISCUSSION

Our case highlights the very rare heterogenous feature of primary CNS lymphoma responding to different treatment regimen. Biopsy of bilateral heterogeneous lesions may be indicated to compare the different molecular features of the lymphoma to find underlying mechanism if they respond to treatment differently. Specific treatment regimen should be selected based on the responsiveness of CNS lymphoma lesions or combination therapy is selected to cover the heterogeneous susceptibility to chemotherapy regimens.

Abstract INTRODUCTION Primary CNS lymphoma is a rare aggressive hematological malignancy. Current chemotherapy for induction phase is HD-MTX single agent or HD-MTX based combination regimen. We report a rare case whose left and right parietal lymphoma lesions in the brain responded to different induction therapy regimens during the induction phase. CASE REPORT A 43-year-old female presented with seizure and her brain MRI showed bilateral parietal brain lesions in January of 2020. Biopsy and work-up revealed primary CNS diffuse large B-cell lymphoma (DLBCL). The patient underwent HD-MTX therapy. Brain MRI showed clear progression of left parietal lymphoma but stable right parietal lymphoma after two cycles of HD-MTX at 8 g/m2. The treatment was switched to a rituximab 750 mg/m2 weekly and temozolomide 150 mg/m2 daily one-week-on and one-week-off regimen. After 8 weeks, her brain MRI showed nearly complete response of her left parietal lymphoma to rituximab/temozolomide but progression of her right parietal lymphoma. She was switched back to HD-MTX and completed total 8 cycles. Her right parietal lymphoma lesion showed complete response to HD-MTX. The patient is doing well and has been off the treatment over the past 10 months and is waiting for consolidation therapy with autologous stem cell transplantation that has been postponed due to the COVID pandemic. DISCUSSION Our case highlights the very rare heterogenous feature of primary CNS lymphoma responding to different treatment regimen. Biopsy of bilateral heterogeneous lesions may be indicated to compare the different molecular features of the lymphoma to find underlying mechanism if they respond to treatment differently. Specific treatment regimen should be selected based on the responsiveness of CNS lymphoma lesions or combination therapy is selected to cover the heterogeneous susceptibility to chemotherapy regimens.

Fatty acid and triglyceride synthesis increases greatly in response to feeding and insulin. This lipogenic induction involves coordinate transcriptional activation of various enzymes in lipogenic pathway, including fatty acid synthase and glycerol-3-phosphate acyltransferase. Here, we show that JMJD1C is a specific histone demethylase for lipogenic gene transcription in liver. In response to feeding/insulin, JMJD1C is phosphorylated at T505 by mTOR complex to allow direct interaction with USF-1 for recruitment to lipogenic promoter regions. Thus, by demethylating H3K9me2, JMJD1C alters chromatin accessibility to allow transcription. Consequently, JMJD1C promotes lipogenesis in vivo to increase hepatic and plasma triglyceride levels, showing its role in metabolic adaption for activation of the lipogenic program in response to feeding/insulin, and its contribution to development of hepatosteatosis resulting in insulin resistance.

Purpose. This study investigated the impact of the different region of interest (ROI) approaches on measurement of apparent diffusion coefficient (ADC) values in the breast firbroglandular tissue (FT). Methods. Breast MR images of 38 women diagnosed with unilateral breast cancer were studied. Percent density (PD) and ADC were measured from the contralateral normal breast. Four different ROIs were used for ADC measurement. The measured PD and ADC were correlated. Results. Among the four ROIs, the manually placed small ROI on FT gave the highest mean ADC (ADC = 1839 ± 343 [×10^-6 mm²/s]), while measurement from the whole breast gave the lowest mean ADC (ADC = 933 ± 383 [×10^-6 mm²/s]). The ADC measured from the whole breast was highly correlated with PD with r = 0.95. In slice-to-slice comparison, the central slices with more FT had higher ADC values than the peripheral slices did, presumably due to less partial volume effect from fat. Conclusions. Our results indicated that the measured ADC heavily depends on the composition of breast tissue contained in the ROI used for the ADC measurements. Women with low breast density showing lower ADC values were most likely due to the partial volume effect of fatty tissues.

Alzheimer's disease is an age-dependent progressive neurodegenerative disorder that results in impairments of memory and cognitive function. It is hypothesized that oligonol has ameliorative effects on memory impairment and reduced cognitive functions in mice with Alzheimer's disease induced by amyloid β(25-35) (Aβ(25-35)) injection. The protective effect of an oligonol against Aβ(25-35)-induced memory impairment was investigated in an in vivo Alzheimer's mouse model. The aggregation of Aβ25-35 was induced by incubation at 37°C for 3 days before injection into mice brains (5 nmol/mouse), and then oligonol was orally administered at 100 and 200 mg/kg of body weight for 2 weeks. Memory and cognition were observed in T-maze, object recognition, and Morris water maze tests. The group injected with Aβ(25-35) showed impairments in both recognition and memory. However, novel object recognition and new route awareness abilities were dose dependently improved by the oral administration of oligonol. In addition, the results of the Morris water maze test indicated that oligonol exerted protective activity against cognitive impairment induced by Aβ(25-35). Furthermore, nitric oxide formation and lipid peroxidation were significantly elevated by Aβ(25-35), whereas oligonol treatment significantly decreased nitric oxide formation and lipid peroxidation in the brain, liver, and kidneys. The present results suggest that oligonol improves Aβ(25-35)-induced memory deficit and cognition impairment.

Olfactory sensory neurons express just one out of a possible ∼ 1,000 odorant receptor genes, reflecting an exquisite mode of gene regulation. In one model, once an odorant receptor is chosen for expression, other receptor genes are suppressed by a negative feedback mechanism, ensuring a stable functional identity of the sensory neuron for the lifetime of the cell. The signal transduction mechanism subserving odorant receptor gene silencing remains obscure, however. Here, we demonstrate in the zebrafish that odorant receptor gene silencing is dependent on receptor activity. Moreover, we show that signaling through G protein βγ subunits is both necessary and sufficient to suppress the expression of odorant receptor genes and likely acts through histone methylation to maintain the silenced odorant receptor genes in transcriptionally inactive heterochromatin. These results link receptor activity with the epigenetic mechanisms responsible for ensuring the expression of one odorant receptor per olfactory sensory neuron.

The biomass equation is a critical component in genome-scale metabolic models (GEMs): it is used as the de facto objective function in flux balance analysis (FBA). This equation accounts for the quantities of all known biomass precursors that are required for cell growth based on the macromolecular and monomer compositions measured at certain conditions. However, it is often reported that the macromolecular composition of cells could change across different environmental conditions and thus the use of the same single biomass equation in FBA, under multiple conditions, is questionable. Herein, we first investigated the qualitative and quantitative variations of macromolecular compositions of three representative host organisms, Escherichia coli, Saccharomyces cerevisiae and Cricetulus griseus, across different environmental/genetic variations. While macromolecular building blocks such as RNA, protein, and lipid composition vary notably, changes in fundamental biomass monomer units such as nucleotides and amino acids are not appreciable. We also observed that flux predictions through FBA is quite sensitive to macromolecular compositions but not the monomer compositions. Based on these observations, we propose ensemble representations of biomass equation in FBA to account for the natural variation of cellular constituents. Such ensemble representations of biomass better predicted the flux through anabolic reactions as it allows for the flexibility in the biosynthetic demands of the cells. The current study clearly highlights that certain component of the biomass equation indeed vary across different conditions, and the ensemble representation of biomass equation in FBA by accounting for such natural variations could avoid inaccuracies that may arise from in silico simulations.

A detailed understanding of the paths that stem cells traverse to generate mature progeny is vital for elucidating the mechanisms governing cell fate decisions and tissue homeostasis. Adult stem cells maintain and regenerate multiple mature cell lineages in the olfactory epithelium. Here we integrate single-cell RNA sequencing and robust statistical analyses with in vivo lineage tracing to define a detailed map of the postnatal olfactory epithelium, revealing cell fate potentials and branchpoints in olfactory stem cell lineage trajectories. Olfactory stem cells produce support cells via direct fate conversion in the absence of cell division, and their multipotency at the population level reflects collective unipotent cell fate decisions by single stem cells. We further demonstrate that Wnt signaling regulates stem cell fate by promoting neuronal fate choices. This integrated approach reveals the mechanisms guiding olfactory lineage trajectories and provides a model for deconstructing similar hierarchies in other stem cell niches.

Along with early-onset cancers, multiple primary cancers (MPCs) are likely resulting from increased genetic susceptibility; however, the associated predisposition genes or prevalence of the pathogenic variants genes in MPC patients are often unknown. We screened 71 patients with MPC of the stomach, colorectal, and endometrium, sequencing 65 cancer predisposition genes. A subset of 19 patients with early-onset MPC of stomach and colorectum were further evaluated for variants in cancer related genes using both normal and tumor whole exome sequencing. Among 71 patients with MPCs, variants classified to be pathogenic were observed in 15 (21.1%) patients and affected Lynch Syndrome (LS) genes: MLH1 (n = 10), MSH6 (n = 2), PMS2 (n = 2), and MSH2 (n = 1). All carriers had tumors with high microsatellite instability and 13 of them (86.7%) were early-onset, consistent with LS. In 19 patients with early-onset MPCs, loss of function (LoF) variants in RECQL5 were more prevalent in non-LS MPC than in matched sporadic cancer patients (OR = 31.6, 2.73-1700.6, p = 0.001). Additionally, there were high-confidence LoF variants at FANCG and CASP8 in two patients accompanied by somatic loss of heterozygosity in tumor, respectively. The results suggest that genetic screening should be considered for synchronous cancers and metachronous MPCs of the LS tumor spectrum, particularly in early-onset. Susceptibility variants in non-LS genes for MPC patients may exist, but evidence for their role is more elusive than for LS patients.