bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intramolecular C2‐Kinase Domain Interactions Autoinhibit Conventional Protein Kinase
Authors: Callender Julia A , Antal Corina E , Kornev Alexandr P , Yang Yuan , Igumenova Tatyana I , Taylor Susan S , Newton Alexandra C 
Published: November 2023

The signaling output of protein kinase C (PKC) is exquisitely controlled, with its disruption resulting in pathophysiologies. Identifying the structural basis for autoinhibition is central to developing effective therapies for cancer, where PKC activity needs to be enhanced, or neurodegenerative diseases, where PKC activity should be inhibited. Here, we reinterpret a previously reported crystal structure of PKCβII and use docking and functional analysis to propose an alternative structure that is consistent with previous literature on PKC regulation. Mutagenesis of predicted contact residues establishes that the Ca2+‐sensing C2 domain interacts intramolecularly with the kinase domain and the carboxyl‐terminal tail, locking PKC in an inactive conformation. Applying a similar approach towards another conventional PKC isozyme, PKCα, confirmed C2 domain‐mediated autoinhibition as a shared mechanism among conventional PKC isozymes. Ca2+‐dependent bridging of the C2 domain to membranes provides the first step in activating PKC via conformational selection. Therefore, elucidation of the structural basis for autoinhibition of PKC unveils a unique direction for therapeutically targeting PKC activity.Support or Funding InformationThis work was supported by NIH grants GM43154 to A.C.N. and DK54441 to A.C.N. and S.S.T. C.E.A. was supported in part by the University of California, San Diego, Graduate Training Program in Cellular and Molecular Pharmacology (T32 GM007752) and the National Science Foundation Graduate Research Fellowship (DGE1144086).
The Role of Ste20‐like Kinase (SLK) in TGFbeta‐activated Kinase 1 (TAK1)‐mediated Pathways
Authors: Tseng Ping‐Hui , Liao Jia‐Wei , Chen I‐Ting 
Published: November 2023

Mitogen‐activated Protein Kinases (MAPKs) are activated in various signaling pathways, and thus, critical for different biological functions. As the member in Ste20‐related kinases, Ste20‐like kinase, SLK, has been suggested to play an important role in apoptosis and cytokinesis. Here, we investigate the interaction between SLK and TGFbeta‐activated kinase 1 (TAK1), which is a key MAP3K in innate immunity. We found that p38 activation is declined in SLK‐silencing macrophages upon LPS engagement. On the other hands, SLK overexpression is able to specifically enhance TAK1‐mediated p38 activation, but has no effect on JNK. In conclusion, we demonstrate that a novel role of SLK in TLR pathways and the mechanism for distinct activation of MAPK signaling.Support or Funding InformationMOST‐102‐2320‐B‐010‐027‐MY3
The Preparation and Screening of Several Novel Bacterial Homoserine Lactone Autoinducers
Authors: Sengstack Janine , Aquino Ashley , Schilling Kevin , Davies Jocelyn , Lehrer Joshua , Ng Cheryl , Armstrong Megan , Souza Lucas , Villaroman Joanne , Santos Riley , Mason Marcos , Brummitt Mary , Gruver Megan , Abadi Shayda , Meisenheimer Kristen , Fidopiastis Pat 
Published: November 2023

The work described here explores the synthesis of known and potentially novel autoinducing molecules. Autoinducers, are small signaling molecules bacteria use to communicate to sense population density and control gene expression. Bacterial quorum sensing is the term used to describe this communication process. Two autoinducers have already been prepared in our lab: p‐coumaroyl homoserine lactone (p‐C‐HSL) and the novel N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone. The quorum sensing activities of both of these molecules have been tested in the Vibrio fisheri bacteria through established collaborations in the Fidopiastis lab here at Cal Poly. Luminescent/growth data suggests Vibrio fisheri responds to N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone but has diminished luminescence compared to the native autoinducer, N‐(3‐oxohexanoyl) homoserine lactone. Vibrio fischeri does not respond to p‐C‐HSL. However, p‐C‐HSL is a known autoinducer in the photosynthetic bacterium Rhodopseudomonas palustris. Reactivity profiling of both p‐C‐HSL and N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone is currently in progress to generate an extensive collection of reactivity data and novel derivatives. Lastly, the synthesis of another potential autoinducer, N‐3‐oxohept‐6‐enoyl‐L‐homoserine lactone is also being prepared in our lab; all of these molecules and derivatives will be tested for quorum sensing activity in the Vibrio fischeri bacteria.Long Range Research Goals: Because the quorum sensing mechanism of Vibrio fischeri is similar to that in other quorum sensing bacteria, these results can be used to demonstrate that synthetic autoinducers can trigger either a similar or possibly inhibited quorum sensing response. Further research would involve extrapolating this result to other quorum sensing bacteria behaviors, such as the production of toxins or antibiotic resistance. A potential goal would be to create an autoinducer that ultimately shuts down bacterial communication thereby inhibiting the formation of toxins in the first place.Support or Funding Information

California Polytechnic State University, College Based Fee Fund
Tumor Suppressors Klotho and 1,25‐Dihydroxyvitamin D3 Cooperate via Synergistic Inhibition of Oncogenic Wnt/β‐Catenin Signaling
Authors: Khan Zainab , Khan Sameera , Sandoval Ruby , Whitfield G. Kerr , Haussler Mark R. , Jurutka Peter W. 
Published: November 2023

The human klotho gene encodes a protein that can generate two isoforms: a single‐pass transmembrane protein (mKlotho) or a secreted peptide (sKlotho) formed from the cleavage of the former. The two isoforms likely possess physiologically unique roles, as mKlotho is known to serve as a membrane‐bound coreceptor for FGF23, while sKlotho may function as an endocrine factor and/or as an enzyme that modifies glycans of cell surface glycoproteins. Due to its putative interactions with several intracellular signaling pathways, klotho has been proposed as an anti‐aging protein and tumor suppressor gene. Intracellular signaling may potentially involve the vitamin D and the Wnt/β‐catenin pathways. Vitamin D, a bioactive lipid and essential nutrient, is acquired via endogenous synthesis upon skin exposure to UVB‐radiation or through dietary intake. Activated 1,25‐dihydroxyvitamin D3 (1,25D) binds to and stimulates the nuclear vitamin D receptor (VDR), which acts as a central factor in bone and mineral homeostasis, as well as a potential chemopreventative agent through its ability to promote cellular differentiation, while inhibiting growth and division. In contrast, the Wnt/β‐catenin signaling pathway can drive enhanced cellular proliferation leading to numerous types of cancers, especially colorectal neoplasia. We hypothesized that sKlotho and vitamin D/VDR may function collectively to inhibit the tumor‐inducing properties of the β‐catenin pathway and that sKlotho may modulate VDR activity. In order to assess the influences of sKlotho and 1,25D on VDRE‐mediated transcription and Wnt/β‐catenin signaling, transcriptional assays and quantitative real time PCR (qPCR) were conducted in embryonic kidney (HEK293) and colon cancer (HCT116) cell lines. We also analyzed the effects of an NAD‐dependent deacetylase sirtuin‐1 (SIRT1), a potential VDR modulator that is activated by resveratrol, on the β‐catenin signaling pathway. Our results revealed an increase in the transactivation capacity of VDR in the presence of 1,25D, SIRT1, and sKlotho. Additionally, sKlotho, SIRT1 and 1,25D were shown to independently and synergistically inhibit β‐catenin activity. The data also indicated functional differences between the two isoforms of klotho, as mKlotho was shown to enhance β‐catenin activity, suggesting that the proposed anti‐aging effects of klotho are presumably directed by the secreted isoform. In conclusion, our study suggests a role for sKlotho as a tumor suppressor and further points to the potential for molecular crosstalk between vitamin D and klotho signaling to elicit optimal human health.Support or Funding InformationNational Institutes of Health Grants DK033351 to MRH and CA140285 to PWJ
Regulator of G Protein Signaling 6 (RGS6) Protects Against Neurodegeneration and Motor Dysfunction in the Unilateral 6‐hydroxydopamine (6‐OHDA) mouse model of Parkinson's Disease
Authors: Luo Zili , Ahlers Katelin E , Yang Jianqi , Alberico Stephanie , Narayanan Nandakumar S , Fisher Rory A 
Published: November 2023

PD is a devastating, and currently untreatable, neurological disease resulting from death of a subset of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). These neurons normally project to the striatum and release DA to postsynaptic targets that control motor behavior. Loss of these SNc DA neurons leads to the hallmark motor deficits of this disease: bradykinesia, rigidity and resting tremors. The reason for the greater sensitivity of SNc neurons to degeneration is unknown. We and our collaborators recently discovered that RGS6 is required for the adult survival of SNc DA neurons whose loss causes PD. RGS6 is restrictively expressed in these neurons and knockout of RGS6 in mice profoundly reduced survival of these neurons. Specifically, RGS6−/− mice exhibited an age‐dependent degeneration of SNc DA neurons, DA loss in the SNc and striatum and motor deficits. While PD is primarily a disease of aging, environmental toxins can produce selective SNc DA neuron death in humans and vertebrates and induce PD motor symptoms. While our findings demonstrate that RGS6 suppresses development of PD in mice without a provoking stimulus we wondered if it would protect against neurotoxic insult. To test this possibility, we administered saline or a submaximal dose of the neurotoxin 6‐OHDA (1 μg) by stereotaxic injection in the SNc of 1 yr old wild type (WT) and RGS6−/− mice and assessed motor behaviors after 2 wks. 6‐OHDA injection provoked loss of RGS6 DA neurons in the SNc in WT mice as well as motor deficits in both groups of mice. Automated gait analysis revealed a decrease in stride length and increased stride frequency in 6‐OHDA vs saline treated mice though RGS6−/− mice exhibited greater changes in these parameters compared to WT mice. Similarly while 6‐OHDA injection impaired accelerating rotarod performance in both groups of mice, RGS6−/− mice had a shorter latency to fall compared to WT mice. RGS6−/− mice also showed greater amphetamine‐induced net ipsilateral rotations and less contralateral paw contact following 6‐OHDA injection compared to WT mice. We also measured forebrain dopamine and its metabolites by in both the non‐injected and 6‐OHDA injected sides of the brains of WT and RGS6−/− mice. Though 6‐OHDA injection induced a significant decrease in forebrain DA content and increases in DOPAC/DA ratio in both sets of mice, the loss of DA and the increase in DOPAC/DA was higher in RGS6−/− mice compared to WT mice. These findings provide the first evidence that RGS6 plays a critical neuroprotective role in neurotoxin‐induced neurodegeneration and motor dysfunction in the most well developed mouse model of PD. These findings identify RGS6 as a potential therapeutic target for development of neuroprotective approaches in PD.Support or Funding InformationSupported by NIH CA161882, AHA 14GRNT20460208
STING is Involved in the Development of Aortic Aneurysm and Dissection
Authors: Guardado Christopher , Zhang Lin , Coselli Joseph S , Shen Ying H , LeMaire Scott A 
Published: November 2023

ObjectivesAortic aneurysm and dissection (AAD) is associated with significant morbidity and mortality. Less than 20% of AAD cases are caused by genetic defects, whereas more than 80% are classified as sporadic. Sporadic AAD results from a progressive loss of smooth muscle cells in the tunica media. However, the molecular mechanisms that lead to the development and pathology of sporadic AAD remain poorly understood. STING (stimulator of interferon genes) is involved in inflammation in response to endoplasmic reticulum stress and DNA damage. Our preliminary data indicate that STING plays a critical role in AAD development. The objective of the current study was to elucidate the molecular pathways by which the STING‐mediated innate immune response contributes to the development of AAD.Methods and ResultsEight‐week‐old Sting−/− mice and wild type mice were either challenged with a high‐fat diet for 8 weeks and an angiotensin II infusion during the last 4 weeks or remained unchallenged for the study period. Aortas from the Sting−/− and wild type mice were stained with markers for smooth muscle cells (SM22a), inflammatory cells (CD68 for macrophages, matrix metalloproteinase [MMP]‐2, and MMP‐9), fibroblasts (fibroblast‐specific protein 1 [FSP1]), and necroptosis (receptor‐interacting protein kinase 3 [RIP3] and mixed lineage kinase domain‐like protein [MLKL]). Qualitative analysis of the stained images showed that aortic challenge induced a significant decrease in the smooth muscle cell marker but increases in CD68, MMP‐2, FSP1, and RIP3 in the aortic smooth muscle cells in wild type mice. Importantly, these changes were significantly reduced in aortas from the challenged Sting−/− mice, as compared to those from challenged wild type mice.ConclusionsOur study suggests that STING may contribute to a switch in smooth muscle cell phenotype and necroptosis, leading to a loss of smooth muscle cells during AAD development.Support or Funding InformationBaylor College of Medicine and NIH grants
The Role of Nrf2 in Neuroinflammation and the Impact of Botanicals
Authors: Krepel Stacey A , Hogan Mary B , Mangum Sally , Kuhn Thomas B 
Published: November 2023

Persistent inflammatory and oxidative stress is largely responsible for the progressive loss of neuronal integrity and connectivity underlying the continuous decline of cognitive function associated with most chronic CNS disorders as well as normal aging. The transcription factor Nrf2, a master redox regulator, plays a pivotal role in the antioxidant defense of non neuronal and neuronal cells. Nrf2 remains sequestered in the cytosol of cells under basal conditions tightly bound to its repressor Keap1 and upon oxidative stress dissociates from Keap1 and translocates into the nucleus to stimulate transcription of antioxidant defense mechanisms. It is not clear how duration and extent of oxidative stress impact activation and nuclear translocation of Nrf2 in neuronal cells. Exposure of SH‐SY5Y human neuroblastoma cells to peroxide (250 μM H2O2, 1 h) considerably increased the presence of Nrf2 in the nuclear fraction indicative of translocation of Nrf2 from the cytosolic to the nuclear compartment. Immunocytochemistry against Nrf2 corroborated this finding. Exposure of SH‐SY5Y neuroblastoma cells (1 h) to the proinflammatory cytokine TNFa at concentrations ranging from 50 ng/ml to 400 ng/ml triggered the translocation of Nrf2 into the nucleus where as prolonged exposure (4 h) to TNFa (200 ng/ml) revealed significantly stronger presence of Nrf2 in the nuclear compartment. However, prolonged exposure of SH‐SY5Y cells to TNFa (24 h) at concentrations of 200 ng/ml or higher also resulted in significant cell death due to oxidative stress. Together these findings suggest that, in response to TNFa stress, Nrf2‐enhanced antioxidant defenses were insufficient. One of the many health benefits of nutrition rests on the capacity of distinct botanicals to directly act on biochemical mechanisms rather than through passive antioxidant capacities. Several botanicals including some polyphenols have the potency to stimulate Nrf2 activity and thus increase antioxidant defense mechanisms. We demonstrated that supplementation of SH‐SY5Y neuroblastoma cells with crude extracts or non polar extracts (5 μg/ml each) obtained from Alaska wild bog blueberries significantly increased neuronal viability in the prolonged presence of 200 ng/ml TNFa. Incubation of SH‐SY5Y cells with distinct blueberry extracts alone stimulated Nrf2 activation, which could at least partially explain the reported neuroprotective potency of diets rich in berry fruits. Understanding the regulation of Nrf2 through botanicals could provide vital insight for developing neuroprotective strategies applicable to an array of neurodegenerative diseases.Support or Funding InformationSupported in part by NIH grants RL56M118990, 1UL16M18991, TL4GM118992, and generous donations from the Alzheimer'r Resources of Alaska. The work is solely the responsibility of the authors and does not necessarily represent the official view of the National Institutes of Health
Peptide inhibition of crosstalk between autophagy and phagocytosis as a novel anti‐septic shock therapeutic strategy
Authors: Yang Chul‐Su 
Published: November 2023

Sepsis is a life threatening disease characterized by inflammation of the entire body, also known as systemic inflammatory response syndrome (SIRS). Upon microbial infection, p22phox‐gp91phox NADPH oxidase complexes produce Reactive Oxygen Species (ROS) critical for the elimination of invading microbes. However, excess production of ROS represents a key element in the cascade of deleterious processes in sepsis. We have recently discovered the direct crosstalk between autophagy and phagocytosis machineries by demonstrating that the Run/cysteine‐rich‐domain‐containing‐Beclin1‐interacting autophagy protein (Rubicon) interacts with p22phox upon microbial infection, facilitating the phagosomal trafficking of the p22phox‐gp91phox NADPH oxidase complex to induce a ROS burst, inflammatory cytokine production, and thereby, potent anti‐microbial activities. Remarkably, the N‐terminal eight‐amino‐acid short peptide derived from p22phox, called the N8 peptide, was sufficient for Rubicon interaction and thus, capable of robustly blocking the Rubicon‐p22phox interaction and profoundly suppressing ROS and inflammatory cytokine production. Consequently, treatment of the N8 peptide dramatically reduced the mortality of lipopolysaccharide (LPS)‐induced endotoxic sepsis and Cecal‐Ligation‐and‐Puncture (CLP)‐induced polymicrobial sepsis in mice, and Escherichia coli infection‐induced sepsis in rhesus monkeys. This study demonstrates a new anti‐sepsis therapeutic strategy by blocking crosstalk between autophagy and phagocytosis innate immunity machineries, representing a potential paradigm shift for urgently needed therapeutic intervention against this life‐threatening SIRS.Support or Funding InformationThis work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF‐2014R1A1A1006117).
Modeling the Role of Impaired Akt Kinase Signaling in the Susceptibility to Stress
Authors: Willock Christine D , Berdux Nicholas C , Franke Thomas F 
Published: November 2023

BackgroundAkt kinase plays a key role in neuronal cell function and survival. Biochemical studies on human postmortem brains indicate significant changes in Akt signaling in depression and suicide. AKT1 mutations also are a liability in psychiatric diseases such as schizophrenia. These noteworthy findings suggest an important role for intact Akt signaling in mood regulation.MethodsOur studies have examined mouse models of Akt deficiency in anxiety‐and depression‐like behaviors, and their responsiveness to antidepressants and psychostimulants. In addition to genomic Akt knockout mice for all three Akt isoforms (Akt1, Akt2 and Akt3), we employed Cre‐dependent recombination to produce Akt1 deficiency in specific brain regions and neuron populations.ResultsFollowing the social defeat regimen, Akt1–deficient mice exhibited increased susceptibility to the detrimental effects of chronic stress. Antidepressant treatment failed to ameliorate depression‐like behaviors in the mutants when compared to wild‐type controls. Mice with conditional Akt1 deficiency exhibited a spectrum of phenotypes after completing the chronic social defeat paradigm: Akt1 ablation in the frontal cortex significantly decreased resilience, while ablation in other brain areas and specific neuron populations increased resilience. Similarly, ablation of Akt1 in different brain regions produced distinct and opposing results when measuring locomotor responsiveness to cocaine.DiscussionOur results in Akt1‐mutant mice converge with biochemical and genetic findings in neuropsychiatric patients and confirm the critical requirement for intact Akt signaling in mood regulation. Based on our findings in conditional Akt1 mutant mice, we predict a significant role for frontal cortical Akt signaling in stress resilience and antidepressant response. Our experiments suggest conditional Akt1 mutant mice as a tractable genetic model to investigate brain region‐specific contributions of Akt signaling to mood regulation. These mutants aid in understanding how circuit‐specific Akt1 deficiencies may become liabilities Conditional Akt1‐mutant mice also illustrate specific contributions of Akt signaling to the function and output of distinct neuronal circuits.Support or Funding InformationThis work was supported in part by NIH grants DA032280, OD018339 and OD018340, and by American Foundation for Suicide Prevention (AFSP) award SRG‐1‐135‐11.
Sex‐ and Corticotropin‐releasing Factor Receptor 2‐dependent Actions of Urocortin 1 During Colitis
Authors: Hasdemir Burcu , Matloubian Mehrdad , Garnett Elizabeth A , Heyman Melvin B , Bhargava Aditi 
Published: November 2023

We investigated whether corticotropin‐releasing factor receptor 2 (CRF2R) and its high affinity agonist urocortin 1 (Ucn1) mediate sex‐specific signaling and immune responses using an in vivo model of inflammatory bowel disease (IBD). Male and female wild‐type (WT) and CRF2R heterozygous (CRF2R+/−) mice, immunoassays, flow cytometry, and microscopy, were used to examine sex‐specific responses. CRF2R+/− mice of both sexes were more susceptible to colitis‐induced mortality than their WT littermates. Ucn1 rescued male CRF2R+/− mice from colitis‐induced mortality, whereas it increased mortality in female CRF2R+/− mice. Ucn1 restored colon length, spleen and adrenal mass, and decreased colonic TNF‐α and IL‐1β levels to baseline levels in male CRF2+/− mice alone. Treatment with monoclonal anti‐TNF‐a ameliorated colitis‐induced inflammation in both sexes, suggesting that Ucn1 actions are upstream of TNF‐α and gender‐specific. CRF2R+/− mice of both sexes showed decreased phosphorylation of MAPK p38 and cytoprotective heat shock protein 27 (Hsp27) levels. Ucn1 restored p‐Hsp27 levels in male CRF2R+/− mice alone. Baseline expression of the chaperone protein Hsp90 was reduced in male CRF2R+/− mice to start with and did not change during colitis or after Ucn1 treatment, suggesting that CRF2R interaction with Hsp90 is critical. Expression levels and subcellular localization of CRF2R and Ucn1 in pediatric IBD patients was dysregulated and gender‐specific. To conclude, CRF2R is a key determinant of the observed sex‐specific immune and cellular signaling responses. We established that Ucn1 mediates sex‐specific responses during IBD via CRF2R, emphasizing the need for inclusion of females in preclinical studies.Support or Funding InformationNIH/NIDDK R01‐080787 to AB