Biology subjects

Rendleman, J.

Publications and source records attributed to Rendleman, J..

6 recordsLinked to original sources

bioRxiv2025

CDK4/6 inhibition induces a DNA damage-independent senescence-associated secretory phenotype driven by delayed activation of NF-κB

Cellular senescence consists of regulated cell phenotypes associated with permanent exit from the cell cycle in response to stressors such as genomic instability. The consequences of senescence go beyond individual cells due to the senescence associated secretory phenotype (SASP), which can induce inflammation in neighboring cells. Some cancers respond to CDK4/6 inhibitors (CDK4/6i)--a family of targeted therapies that inhibit proliferation--with a senescence-like phenotype in the absence of DNA damage. We asked how the SASP and the transcriptional regulatory profile triggered by CDK4/6i-driven arrest compares to the canonical NF-{kappa}B-regulated SASP triggered by DNA damage. We profiled the temporal dynamics of transcriptional regulation in response to the CDK4/6i, palbociclib, and the DNA damaging agent, doxorubicin. We found that, although upregulation of NF-{kappa}B driven-SASP genes is shared across both drugs, it is delayed in CDK4/6i. This coincides with slower enhancer activation and epigenetic changes. Interestingly, ATM/ATR inhibition does not affect CDK4/6i-induced NF-{kappa}B nuclear localization, pointing to an alternative mechanism driving NF-{kappa}B activity in the absence of DNA damage. Inhibiting NF-{kappa}B suppresses the expression of shared SASP genes without reversing stable arrest. This points to SASP manipulation as a potential therapeutic strategy, and resolves an ongoing controversy about the nature of cell cycle arrest-driven SASP.

cancer biology↗

bioRxiv2022

Complex changes in serum protein levels upon recovery from SARS-CoV2 infection

The COVID-19 pandemic, triggered by severe acute respiratory syndrome coronavirus 2, has affected millions of people worldwide. Much research has been dedicated to our understanding of COVID-19 disease heterogeneity and severity, but less is known about recovery associated changes. To address this gap in knowledge, we quantified the proteome from serum samples from 29 COVID-19 convalescents and 29 age-, race-, and sex-matched healthy controls. Samples were acquired within the first months of the pandemic. Many proteins from pathways known to change during acute COVID-19 illness, such as from the complement cascade, coagulation system, inflammation and adaptive immune system, had returned to levels seen in healthy controls. In comparison, we identified 22 and 15 proteins with significantly elevated and lowered levels, respectively, amongst COVID-19 convalescents compared to healthy controls. Some of the changes were similar to those observed for the acute phase of the disease, i.e. elevated levels of proteins from hemolysis, the adaptive immune systems, and inflammation. In contrast, some alterations opposed those in the acute phase, e.g. elevated levels of CETP and APOA1 which function in lipid/cholesterol metabolism, and decreased levels of proteins from the complement cascade (e.g. C1R, C1S, and VWF), the coagulation system (e.g. THBS1 and VWF), and the regulation of the actin cytoskeleton (e.g. PFN1 and CFL1) amongst COVID-19 convalescents. We speculate that some of these shifts might originate from a transient decrease in platelet counts upon recovery from the disease. Finally, we observed race-specific changes, e.g. with respect to immunoglobulins and proteins related to cholesterol metabolism.

immunology↗

bioRxiv2022

Proteomic signatures of the serological response to flu vaccination in a large human cohort study

The serological response to the influenza virus vaccine is highly heterogeneous for reasons that are not entirely clear. While the impact of demographic factors such as age, body mass index (BMI), sex, prior vaccination and titer levels are known to impact seroconversion, they only explain a fraction of the response. To identify signatures of the vaccine response, we quantified 273 proteins from serum samples of 160 flu vaccine recipients (2019-2020 season). We found that levels of proteins functioning in cholesterol transport were positively associated with seroconversion, likely linking to the known impact of BMI. When adjusting seroconversion for the demographic factors, we identified additional, unexpected signatures: proteins regulating actin cytoskeleton dynamics were significantly elevated in participants with high adjusted seroconversion. Viral strain specific analysis showed that this trend was largely driven by the H3N2 strain. Further, we identified complex associations between adjusted seroconversion and other factors: levels of proteins of the complement system associated positively with adjusted seroconversion in younger participants, while they were associated negatively in the older population. We observed the opposite trends for proteins of high density lipoprotein remodeling, transcription, and hemostasis. In sum, careful integrative modeling can extract new signatures of seroconversion from highly variable data that suggest links between the humoral response as well as immune cell communication and migration.

immunology↗

bioRxiv2022

Molecular signatures of proteostasis control in motor neurons with different sensitivity to Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a fatal adult neurodegenerative disease characterized by proteostasis dysregulation, resulting in progressive loss of spinal and upper motor neurons. A subset of cranial motor neurons resistant to ALS-stress survive until late stages of the disease. To investigate these differences, we exploited a unique platform of induced cranial and spinal motor neurons (iCrMNs and iSpMNs, respectively). Exposing both cell types to proteotoxic stress, we quantified transcriptome and proteome changes over 36 hours for a core set of >8,200 genes. While mRNA and protein changes under stress were congruent for many genes, cell-type specific differences manifested at either the RNA or protein level, but less at both. At the protein level, iCrMNs and iSpMNs differed significantly with respect to abundance of many membrane proteins, including synaptic proteins, solute carriers, adhesion molecules, and signaling molecules suggesting that the superior stress survival of iCrMNs involve diverse pathways supporting neuronal function. Other differences included genes involved in ribosome biogenesis and subunits of the core proteasome. We investigated the role of proteasomal degradation in more detail. Our data showed that although stress reduces proteasome activity in both neuronal types, iCrMNs had significantly more abundant and active 26S proteasome than iSpMNs, which indicate a higher capacity for the degradation of ubiquitinated proteins. We identified a new regulator of this better performance, i.e. the nuclear proteasome activator Ublcp1, whose inhibition sensitized iCrMNs, but not iSpMNs, to stress and abolished their higher survival rates. The results suggest that the two neuronal cell types regulate and use the degradation machinery differently under normal and stress conditions. Overall, this work demonstrates the value of unbiased system-wide analyses in generating hypotheses on differential proteostasis regulation in cranial and spinal motor neurons.

systems biology↗

bioRxiv2021

Regulatory start-stop elements in 5' untranslated regions pervasively modulate translation

Sequence elements within the 5 untranslated region (UTR) of eukaryotic genes, e.g. upstream open reading frames (uORFs), control translation of eukaryotic genes. We describe an element consisting of a start codon immediately followed by a stop codon which is distinct from uORFs in the lack of an elongation step. Start-stops have been described for specific cases, but their widespread impact has been overlooked. Start-stop elements occur in the 5UTR of 1, 417 human genes and are more often occupied with a ribosome than canonical uORFs or control sequences. Start-stops efficiently halt ribosomes without evidence for accelerated RNA turnover, therefore acting as a barrier for the scanning of the small ribosomal subunit and repressing downstream translation. Our results suggest a model by which the ribosome undergoes repeated cycles of termination and partial ribosomal recycling, during which the large subunit detaches, but the 40S subunit with the Met-tRNAiMet remains associated with the mRNA to be rejoined by the 60S subunit. Start-stop elements occur in many transcription factors and signaling genes, and affect cellular fate via different routes. We investigate the start-stop element in several genes, i.e. MORF4L1, SLC39A1, and PSPC1, and in more detail in ATF4.

systems biology↗

bioRxiv2018

Quantifying multi-layered expression regulation in response to stress of the endoplasmic reticulum

The mammalian response to endoplasmic reticulum (ER) stress dynamically affects all layers of gene expression regulation. We quantified transcript and protein abundance along with footprints of ribosomes and non-ribosomal proteins for thousands of genes in cervical cancer cells responding to treatment with tunicamycin or hydrogen peroxide over an eight hour time course. We identify shared and stress-specific significant regulatory events at the transcriptional and post-transcriptional level and at different phases of the experiment. ER stress regulators increase transcription and translation at different times supporting an adaptive response. ER stress also induces translation of genes from serine biosynthesis and one-carbon metabolism indicating a shift in energy production. Discordant regulation of DNA repair genes suggests transcriptional priming in which delayed translation fine-tunes the early change in the transcriptome. Finally, case studies on stress-dependent alternative splicing and protein-mRNA binding demonstrate the ability of this resource to generate hypotheses for new regulatory mechanisms.

systems biology↗