bluuebunny/crossref_metadata_2025 huggingface dataset:
Pilot study of career development and personal values among Biochemistry students
Authors: Lo Fai‐Hang
Published: May 2022

Career development of Biochemistry graduates from the Universities has drawn some attention to the educationists in Hong Kong these days; on the one hand, the unemployment rate among the youth was high. On the other, Biochemistry graduates might be unsure about their niche in the labour market. We conducted a pilot study focusing on the career development and personal values among students studying biochemistry: Secondary School Students (α) studying general Biochemistry; University Students studying Clinical Biochemistry (β) and Exercise Biochemistry (γ) were surveyed. The three groups of students were asked if they knew their own career preferences; α, β, and γ rated 6.64±0.77, 6.83±0.53, and 6.18±0.71, respectively. For the nature of their preferred jobs based on Holland Codes, most α (64.3%) preferred ‘investigative’. While most β (66.7%) preferred ‘conventional’ and most γ (63.6%) preferred ‘social’. The Holland Codes of α, β, and γ were found to be ‘IRC’, ‘CIR’, and ‘SR’, respectively; all groups shared ‘realistic’ as the common component, implicating their interest in conducting experiments. Considering the satisfaction of their resume, the ratings of α, β, and γ were 5.29±0.51, 4.56±0.39, and 5.18±0.53, respectively. For interview skills, their ratings were 4.43±0.76, 5.33±0.41, and 5.82±0.74, respectively. Regarding their confidence in career development, the ratings were 6.00±0.49, 4.94±0.45, and 4.73±0.64, respectively. In terms of personal values based on the Barrett Model, clusters were observed: the most popular personal values in α were wisdom (8.04%) and accountability (7.14%); adaptability (6.92%), well‐being (6.92%), and self‐discipline (6.15%) were reported in β. Whereas in γ, health (6.92%) and ease with uncertainty (5.75%) were the most popular. Taken together, about two‐third of the students knew their own career preferences, which appeared to be associated to the courses they took. The students were observed to have diverse personal values dependent on their age and the subjects they chose. Overall, the University Students with various personal values appeared to be less satisfied with and less confident in their career development. Some follow‐up measures should be tailored and implemented.
Engineered Nanoparticles as Potential Therapeutics for Acute Myeloid Leukemia
Authors: Syrovets Tatiana , Gaiser Ann‐Kathrin , Schmiech Michael , Simmet Thomas
Published: May 2022

Acute myeloid leukemia (AML) is a malignancy associated with poor prognosis. Particularly, older patients suffer greatly from the standard chemotherapy and have a 5‐year survival of only 4%. Hence, new therapeutic agents with higher specificity and lower general cytotoxicity are urgently required.

We have discovered that positively charged amino‐functionalized polystyrene nanoparticles (NP‐PS+) induce accumulation of acidic vesicular organelles with elevated pH and impaired processing of procathepsin B leading to mTOR inhibition, activation of autophagy, and induction of caspase‐dependent apoptosis in leukemia cells, but not in normal human macrophages. The antileukemic effect of NP‐PS+ was also preserved in vivo, where NP‐PS+ inhibited proliferation and induced apoptosis in leukemia xenografts grown on chick chorioallantoic membranes.

Similar to polystyrene particles, amino‐functionalized gold nanoparticles (NP‐Au+) exhibited selective cytotoxicity towards AML cell lines as well as primary patient‐derived AML cells. Thus, NP‐Au+ particles induced cell death in primary human leukemia cells and reduced their colony‐forming potential, whereas normal hematopoietic cells remained unaffected by the treatment with NP‐Au+. NP‐Au+ targeted specifically the oxidative mitochondrial respiration, which is, different to normal hematopoietic cells, the main source of energy production in AML blasts and leukemic stem cells. Different to NP‐Au+, conventional chemotherapeutics such ascytarabine act in a cell cycle‐dependent manner and target only on proliferating AML blasts but not on quiescent leukemic stem cells. In agreement with the in vitro data, NP‐Au+ exhibited antileukemic efficacy against primary human AML xenografted into mice applied either as monotherapy or as a cytarabine combination regimen in the absence of detectable adverse events.

Thus, this engineered nanomaterial that targets particularly resistant quiescent leukemic stem cells holds great promise as a novel nanotherapeutic for the treatment of acute myeloid leukemia independent of its cytogenetic profile.
Identification of Potential Cellular Responses Triggered by Stereoisomeric DNA Interstrand Crosslinks Produced by Mitomycins in MCF‐7 Cells
Authors: Rosas Melissa , Zacarias Owen , Clement Cristina C. , Cheng Shu Yuan , Champeil Elise
Published: May 2022

Mitomycin C (MC) is a DNA alkylating agent broadly used in chemotherapy. MC and Decarbamoylmitomycin C (DMC), a synthetic MC derivative which lacks the carbamoyl at the C10 position, can form interstrand crosslinks (ICLs) between the exocyclic amines of opposing deoxyguanosine moieties. These ICLs are responsible for the cytotoxicity of mitomycins towards cancer cells since they prevent replication of highly proliferating cells. MC and DMC can crosslink DNA in both 5’‐CpG and 5’‐GpC sequence contexts, and the crosslinking is diastereospecific: At 5’‐CpG, mitomycins produce trans‐ICLs whereas cis‐ICLs are found at 5’‐GpC steps. The major ICL formed by Mitomycin C in culture cells is the trans‐ICL whereas decarbamoylmitomycin C yields the stereoisomeric cis‐ICL preferentially. Our overarching goal is to synthesize oligonucleotides bearing the cisand trans isomeric crosslinks to investigate the relationship between ICL structure and cellular response. Our hypothesis is that the trans and cis‐ICLs trigger different cellular responses. There is evidence that the ICL produced by DMC triggers a p53 independent cell death and research uncovering mechanisms through which p53 independent cell death occurs is crucial to identify molecular targets to treat tumors with a mutant p53. These tumors represent at least 50% of all cancers. We present here the different synthetic routes to access cis and trans isomeric interstrand crosslinks formed by mitomycins in their reaction with DNA and preliminary label free proteomic studies to identify the stereoisomeric ICLs molecular targets. Proteomic studies were accomplished from MCF‐7 cells transfected with the purified ICLs for 24 hours. They showed several interesting proteins were differently regulated by the trans‐ and cis‐ICLs: (1) TBC1 domain family member 9 which regulates cell proliferation (increased 41% upon treatment with the trans‐ICL treatment, but decreased 50% with the cis‐ICL); (2) Core histone macro‐H2A.2, involved in DNA repair (decreased 75% upon treatment with the trans‐ICL, but increased 89% with the cis‐ICL); (3) Aurora kinase B which inhibits p21 expression and regulates cell cycle (increased 50% upon treatment with the trans‐ICL, but decreased 73% by the cis‐ICL); and (4) Membrane‐associated tyrosine‐ and threonine‐specific cdc2‐inhibitory kinase which acts a negative regulator of G2 to M transition (decreased 36% upon treatment with the trans‐ICL, but increased 5% with the cis‐ICL). In addition, Ingenuity Pathway Analysis was conducted to identify the major molecular pathways impacted by each ICL treatment. In conclusion, we now have identified both ICL molecular targets and cellular responses involved in DNA repair and cell cycle regulation in MCF7 cell lines. Further validations are needed to confirm the results.
Dietary influences on closed‐head traumatic brain injury in a pediatric rodent model
Authors: Smith Allie M. , Ray Trenton J. , Hulitt Alicia A. , Vita Sydney M. , Grayson Bernadette E. , E. Santos Christiano D. S.
Published: May 2022

Traumatic brain injury (TBI) is one of the most common causes of emergency room visits in children, and it is a leading cause of death in juveniles in the United States. Similarly, a high proportion of this population consumes diets high in saturated fats, and millions of children are overweight or obese. Therefore, the goal of the present study was to assess the relationship between diet and TBI outcomes in juvenile rats. In the current study, groups of juvenile male Long Evans rats were provided with a combination of a high fat diet (HFD) and a solution of 10% high‐fructose corn syrup or a standard chow diet. The animals were trained on the Morris water maze (MWM) for two consecutive days to test spatial learning. Rats were then subjected to either mild TBI via the Closed‐Head Injury Model of Engineered Rotational Acceleration (CHIMERA) or sham procedures. Immediately after TBI, the animals’ righting reflexes were tested. Animals were retested in the MWM either three hours or four days post‐injury. The animals were euthanized either four days or seven days post‐injury, and brain samples and blood plasma were collected for QRT‐PCR, immunohistochemistry, and triglyceride assays. Acute HFD intake did not alter the body weight of the weanling rats, but the HFD significantly elevated triglyceride levels by two weeks. Latency to the platform during the MWM training period was not affected by diet. Nor were there any differences in post‐injury time to righting and walking by diet group. However, the TBI rats’ time to righting and walking was significantly reduced compared to the sham rats, p < 0.05. The latency and distance traveled to the platform in the MWM were significantly increased by TBI three hours post‐injury. Alternately, these changes were abolished four days post‐injury. QRT‐PCR revealed that CREB1 and IL1β were increased in the hippocampus. On the other hand, IL6 was increased in the prefrontal cortex as a function of injury. CREB1, IL1β, and IL6 gene expression were significantly elevated by TBI, while CLDN5, IL6, and IL1R1 were increased in the hippocampus due to diet. Immunohistochemistry revealed an increased immunoreactivity of IBA‐1 in the cortex and corpus callosum in the TBI animals, regardless of diet. The results from this study offer evidence that both HFD and TBI influence behavior and biochemical markers in juvenile rats using the novel CHIMERA device.
Proteins of the ubiquitin system in the Shoc2 ‐ ERK1/2 signaling axis and Noonan‐like syndrome with loose anagen hair (NSLAH) RASopathy
Authors: Galperin Emilia , Wilson Patricia , Abdelmoti Lina , Norcross Rebecca , Palayam Malathy
Published: May 2022

The ERK1/2 signaling pathway is critical in organismal development and tissue morphogenesis. Deregulation of this pathway leads to congenital abnormalities with severe developmental dysmorphisms, i.e. RASopathies. The core ERK1/2 cascade relies on scaffold proteins such as Shoc2 to guide and fine‐tune its signals. Mutations in shoc2 lead to the development of the pathology termed Noonan‐like Syndrome with Loose Anagen Hair (NSLAH) RASopathy. However, the mechanisms underlying the functions of Shoc2 and its contributions to disease progression remain unclear.

We found that Shoc2 assembles an elegant multi‐component complex that incorporates several proteins of the ubiquitin system. To fine‐tune the amplitude of ERK1/2 signal transmitted via the complex, Shoc2 tethers the E3 ligase HUWE1, the (AAA+) ATPases, PSMC5 and VCP/p97, and the deubiquitinating enzyme, USP7. All of these enzymes are integral to the intricate feedback mechanism.

Our recent studies demonstrated that ERK1/2 pathway activation triggers the interaction of Shoc2 with the ubiquitin‐specific protease USP7. We identified that in the Shoc2 module, USP7 functions as a molecular “switch” that controls the E3 ligase HUWE1 and the HUWE1‐induced regulatory feedback loop. We also found that disruption of Shoc2‐USP7 binding leads to aberrant activation of the Shoc2‐ERK1/2 axis. The zebrafish vertebrate model was then used to show that Shoc2 congenital mutations affecting Shoc2 interaction with USP7 lead to aberrant Shoc2 ubiquitination and signal transmission. Thus, our studies reveal a role for USP7 in the pathogenic mechanisms underlying NSLAH extending our understanding of how ubiquitin‐specific proteases regulate intracellular signaling.

In summary, our studies are the first to demonstrate that the Shoc2 scaffold employs multi‐protein enzymatic machinery to govern the amplitude of Shoc2‐ERK1/2 signals. We also uncover novel molecular mechanisms underlying the pathogenesis of Noonan‐like syndrome with loose anagen hair. Overall, these studies significantly advance our understanding of the mechanisms by which non‐enzymatic scaffolds regulate the specificity and dynamics of the ERK1/2 signaling networks.
Discerning a Potential Link between MEMO1’s Role in Vascular, Bone, and Craniofacial Development
Authors: Wuebker Samantha , Van Otterloo Eric
Published: May 2022

Embryonic development of craniofacial structures requires the tight integration of multiple tissues and cell‐types. For example, the intersection of neural crest derived mesenchyme with mesoderm derived endothelium (i.e., vasculature) is necessary for craniofacial bone development and mineralization. Despite craniofacial anomalies being the 2nd leading congenital anomaly worldwide, our understanding of how these tissues interact is limited.

Through a forward genetic screen, we previously identified a novel role for the protein encoded by the gene mediator of ERBB2‐driven cell motility 1 (Memo1) in craniofacial development. Global loss of Memo1 resulted in a range of defects, including hypo‐mineralization of the craniofacial skeleton, fully penetrant cleft secondary palate, coupled with widespread vascular abnormalities. Interestingly, while neural crest cell specific deletion of Memo1 recapitulated some aspects of global loss of Memo1, several defects were less apparent—suggesting MEMO1 functions in tissues outside the neural crest during craniofacial development. Further, molecular profiling of craniofacial elements in global Memo1mutants identified significantly altered Vegfa expression, coupled with disrupted vascular development, relative to controls. Based on these observations, along with Memo1’s semi‐ubiquitous expression during development, we hypothesized that MEMO1 functions within the endothelial derived vasculature and this function is necessary for proper craniofacial development.

To test this hypothesis, we have generated a Memo1 endothelial specific mouse knock‐out model. Similar to Memo1 global knock‐outs, and in contrast to Memo1 neural crest knock‐outs and controls, Memo1 endothelial knock‐outs develop vascular hemorrhaging and edema with variable penetrance. Vascular defects are accompanied by gross alterations to craniofacial shape. We are currently utilizing µCT, cell sorting coupled with gene expression profiling, and ex vivo ‘sprouting’ assays to quantify the impact endothelial loss of Memo1 has on craniofacial bone development and mineralization, MEMO1’s molecular role in craniofacial endothelial cells, and MEMO1’s functional role in endothelial cells, respectively.

Overall, in addition to MEMO1’s neural crest cell specific role, our findings extend MEMO1’s function into an additional cell‐type, endothelial cells, during craniofacial development. These data illuminate the molecular pathology for how disrupted neural crest or endothelial cells may lead to human craniofacial disorders.
Embryonic Over‐Expression Of RAGE In Mouse Lung Modulates Thyroid Transcription Factor (TTF)‐1 And Surfactant Expression
Authors: Clarke Derek , Curtis Katrina , Anica Kruyer , Homer Kyle , Grajeda Samuel , Jensen Tyler , Black Joe , Beckett Nathan , Arroyo Juan A. , Reynolds Paul
Published: May 2022

Receptors for advanced glycation end‐products (RAGE) are multi‐ligand cell surface receptors of the immunoglobin superfamily prominently expressed by lung epithelium. Previous experiments demonstrate that over‐expression of RAGE by murine alveolar epithelium throughout embryonic development causes neonatal lethality coincident with significant lung hypoplasia. In the current study, we evaluated the expression of TTF‐1, a homeodomain‐containing transcription factor critical for branching morphogeneis, in mice that differentially expressed RAGE. We also contexualized TTF‐1 expression with the abundance of FoxA2, a winged double helix DNA binding protein that influences respiratory epithelial cell differentiation, and surfactant proteins. Conditional RAGE over‐expression was induced in mice throughout gestation (embryonic day (E)0‐18.5) as well as during the critical saccular period (E15.5‐18.5) of development and analyses were conducted on E18.5 lung tissue. Histology revealed marked loss of lung tissue beginning in the canalicular stage of lung development and continuing throughout the saccular period. We discovered consistently decreased expression for both TTF‐1 and FoxA2 in lungs from TG mice compared to age‐matched controls. We also clarified diminished surfactant protein abundance in TG mice, suggesting possible hindered differentiation and/or proliferation of alveolar epithelial cells under the genetic control of these two critical transcription factors. These results demonstrate that RAGE must be specifically regulated during lung formation and that perturbation of epithelial cell differentiation culminating in respiratory distress and perinatal lethality may coincide with elevated RAGE expression in the lung parenchyma.
Ligands Binding Peptidoglycan‐Associated Lipoprotein as Biomarkers for Sepsis
Authors: Pilo Isabelle , Michel Lea , Torelli Andrew , French Jared , Hicks Katherine , Lawrence Kayla , Ariola Ashton , Woods Conner , Rhodes Anais
Published: May 2022

Peptidoglycan‐Associated Lipoprotein (Pal) is an outer membrane protein conserved among Gram‐negative bacteria. Pal protein binds to peptidoglycan and several outer membrane and periplasmic proteins as part of the Pal‐Tol complex, a system of interacting proteins that link together the outer membrane, the peptidoglycan layer, and the inner membrane. The Pal‐Tol complex is important for maintaining the integrity of the cell envelope and plays a role in the invagination process during cell division. We proposed to identify small molecules that could disrupt the Pal‐TolB interaction and/or Pal‐peptidoglycan binding, as the two binding sites are thought to overlap. As part of a summer research program, funded by the NSF, our team of researchers used the computational program Dock6 to dock a variety of small molecules from the ZINC database in different rigid and flexible conformations. The small molecules that docked the most favorably were linear polycyclic structures that had alcohol and amine groups, such as FMN, capastat, leucal, and ceftriaxone. We also describe our ongoing efforts to develop a binding assay to test the effect of these small molecules on Pal‐TolB and Pal‐peptidoglycan binding. Due to Pal’s role in cell division and cell envelope integrity, we propose that small molecules that disrupt interactions to Pal’s binding partners could serve as potential antibiotics.
HMGB1 is necessary for the Receptors for Advanced Glycation End‐products (RAGE) inhibition of DNA Double Strand Breaks in trophoblast cells
Authors: Kiehl Joe , Curtis Katrina , Clarke Derek , Reynolds Paul R. , Arroyo Juan A.
Published: May 2022

Trophoblasts are critical for a successful pregnancy and they mediate important steps such as implantation and delivery. Increased trophoblast DNA double strand breaks (DNA‐DSBs) is implicated in complicated pregnancies. Our laboratory showed a role for increased nuclear placental receptor for advanced glycation end‐products (nRAGE) in DNA‐DSB repair in trophoblasts. HMGB1 protein (nHMGB1) is a nuclear protein that acts as a chromatin‐binding factor involved the regulation of gene transcription that when released extracellularly, is involved in RAGE mediated inflammatory responses. We tested the hypothesis that nHMGB1 correlated with nRAGE availability during DNA‐DSB in trophoblasts. DSBs were induced in human trophoblasts with cigarette smoke extract (CSE). Assessment of HMBG1, Beclin1 (involved in phagocytosis) and Caspase 3 (pro‐apoptotic) were done by immunoblotting. Immunoprecipitation was used to quantify a RAGE and MNR11 complex. Invasion was measured in trophoblast cells in the presence or absence of an HMGB1 inhibitor (Glycyrrhizin; GLY). Decreased trophoblast nHMGB1 (1.8‐fold; p<0.02) was present during DNA‐DSB and this reduction was reversed (4.5‐fold; p<0.02) with GLY treatment. DNA‐DSBs induced a MRN11‐nRAGE complex (1.4‐fold; p<0.03) in trophoblasts and the complex was decreased (2.5‐fold; p<0.05) by GLY co‐treatment. CSE increased Beclin1 (1.9‐fold; p<0.02) and decreased Caspase 3 (2.2‐fold; p<0.02); however, GLY co‐treatment significantly decreased Beclin1 (9.0‐fold p<0.02) while increasing Caspase 3 (1.2‐fold; p<0.04). Compromised trophoblast invasion was improved (7.0‐fold; p<0.02) with GLY treatment. We conclude that CSE causes DNA‐DSBs in trophoblasts and HMGB1 plausibly regulates nRAGE availability at DNA‐DSBs. We further conclude that Beclin1 and Caspase 3 are regulated by HMGB1 inhibition and that HMGB1 targeting could be a factor in regulating trophoblast invasion during DNA‐DSBs. These studies provide a critical initial step in dissecting tobacco‐mediated placental deficiency.
High‐Density Lipoprotein is Independently Associated with Muscle Mitochondrial Function in Healthy Humans
Authors: Giacona John M. , Petric Ursa B. , Saldanha Suzanne , Smith Scott A. , Rohatgi Anand , Vongpatanasin Wanpen
Published: May 2022

High‐density lipoprotein cholesterol (HDL‐C) is well known to play an important anti‐atherogenic role via reverse cholesterol transport. Increasing number of studies in mice have also suggested a protective role of HDL in preserving muscle mitochondrial function via ApoA1‐induced enhancement of cellular respiration of glucose. However, data in humans are lacking. We therefore hypothesize that HDL levels and/or function are correlated with muscle mitochondrial function in humans. Accordingly, we conducted a cross‐sectional study to determine the relationship between levels and function of HDL and skeletal muscle mitochondrial function in 31 healthy adults without diabetes mellitus or cardiovascular disease. To estimate muscle mitochondrial function, we measured the oxygen recovery time constant (Tau) during supra‐systolic cuff‐occlusions following 2 minutes of rhythmic handgrip exercise at 30% maximal voluntary contraction in the forearm muscle, using near infrared spectroscopy (NIRS). To assess cholesterol efflux capacity (CEC), we used J774 macrophages, radiolabeled cholesterol, and ApoB‐depleted plasma to calculate cholesterol efflux normalized to a pooled sample. Of the 31 subjects, 13 (42%) were female, mean age was 40 +/‐ 16, mean BMI was 23.9 +/‐ 3.4 kg/m^2, and the mean total serum cholesterol was 198.4 +/‐ 43.1 mg/dL. We found a significant inverse correlation between HDL‐C levels and Tau, with a correlation coefficient (r) of ‐0.51 (p < 0.01, Figure. 1a). As expected, a positive correlation is observed between BMI and Tau (r= 0.50, p < 0.01, Figure 1c). In contrast, no significant correlation between fasting triglyceride, plasma glucose, insulin levels or HDL efflux function with Tau were found (all p‐values > 0.05). In conclusion, our study identifies a novel association between circulating HDL levels with muscle mitochondrial function. However, the CEC of our sample was not significantly correlated with Tau, therefore future investigations with larger studies or more measures of HDL function and composition may elucidate these findings. The association of HDL‐C and muscle mitochondrial function may explain increased prevalence of physical inactivity among populations with low HDL‐C, such as those with metabolic syndrome. Additionally, future studies are needed to determine if strategies to improve HDL‐C levels will result in improved muscle mitochondrial function and exercise capacity.
Brave New E‐World: Medical Students’ Preferences for and Usage of Electronic Learning Resources during Two Different Phases of Their Education
Authors: Hortsch Michael , Finn Erin , Ayres Fred , Goldberg Stephen
Published: May 2022

E‐learning strategies have become an essential part of biomedical education. However, why and how students select hardware tools and software formats during their education has not been sufficiently analyzed and documented. Yet, these aspects should be taken into account when designing or offering new e‐learning modalities to learners. Two medical school classes at a major US medical school were surveyed about their use of e‐learning resources during their first year of medical school or their preparation for their first licensing examination (USMLE® Step 1), respectively. Their responses were analyzed for patterns and significant changes. Students’ answers from both classes indicated that computers and computer tablets were considered the most important hardware devices to support students’ learning. During the first year, students often preferred resources that were tailored to the specific courses in their curriculum. In contrast, some preferences changed when students prepared for the USMLE® Step 1, with students shifting almost exclusively to a solitary learning mode using commercial e‐learning resources. Across all phases of medical school education queried, peer advice was the major determinant influencing e‐learning resource selection, with faculty only playing a minor role during the first year of medical school. Videos were the most popular e‐learning modality, and students cited efficient acquisition of knowledge and preparation for examinations as major reasons for e‐learning tool utilization. These data suggest that the selection of e‐learning resources is task‐oriented, with students choosing specific resources based on the challenges they are facing. These factors need to be considered when offering or developing e‐learning resources for medical and other students during different phases of their training.
Inhibition of SGK1 ameliorates ventriculomegaly in a genetic rat model via regulation of TRPV4 in the choroid plexus
Authors: Hochstetler Alexandra E. , Smith Hillary , Reed Makenna , Hulme Louise , Perrotti Nicola , D'Antona Lucia , Schenone Silvia , Musumeci Francesca , Blazer‐Yost Bonnie
Published: May 2022

Hydrocephalus is a clinical manifestation of cerebrospinal fluid (CSF) accumulation, leading to ventriculomegaly and increased intracranial pressure. Diuretics and other pharmacotherapies have failed to treat hydrocephalus in the human population; therefore, treatment options remain exclusively surgical. The need to develop pharmacotherapies for the treatment of hydrocephalus remains an unmet clinical need and paramount to this need is the study of brain fluid regulation. Previous studies in our laboratory identified the transient receptor potential vanilloid 4 (TRPV4) channel as a potential regulatory hub protein in the choroid plexus responsible, in part, for the regulation of CSF production. Antagonists of the TRPV4 channel were shown to ameliorate hydrocephalus in a genetic rat model. The current studies highlight a novel drug target: serum‐ and glucocorticoid‐induced kinase 1 (SGK1) in the choroid plexus. A specific small molecular weight, membrane permeant inhibitor of SGK1, SI113, has shown promising results in cancer and metabolic research in recent years. In other tissues, SGK1 has been shown to phosphorylate and activate TRPV4 at the membrane, indicating SGK1 as an important upstream regulatory kinase. SI113 blocked TRPV4‐mediated transepithelial ion flux and barrier conductance increases in a cell culture model of human choroid plexus epithelia (HIBCPP line), and ameliorated ventriculomegaly in the genetic rat model. In hydrocephalic animals, there is an increased apical membrane signal in the choroid plexus epithelial cells via immunofluorescent localization of p‐SGK1 and TRPV4, but not of pan‐SGK1. This is not accompanied by a significant increase in either protein or transcript abundance as measured by western blotting or qPCR, respectively. The change in localization is, however, attenuated by treatment with SI113. Animals treated with SI113 show no change in amounts of TRPV4 or total SGK1, but do show significantly reduced levels of p‐SGK1. Thus, phosphorylation of SGK1 appears to be crucial for the activation of TRPV4 which is, in turn, a channel protein that is activated during the development of hydrocephalus. Like Trpv4‐/‐mice, Sgk1‐/‐mice do not show overt phenotypes, indicating pharmacological antagonism of the kinase would have minimal off‐target effects. Overall, these data provide a strong preclinical basis for the use of SGK1 inhibitors in the treatment of hydrocephalus.
Where is the primate transverse tarsal joint? Chopart vs. Lisfranc
Authors: Greiner Thomas M.
Published: May 2022

The concept of the transverse tarsal joint is typically associated with accommodative twists of the foot, and with a midfoot flexion known as the midtarsal break. The specific joints associated for these motions are often assumed, but are rarely validated. The two most common candidates are “Chopart’s Joint,” which separates the cuboid and navicular from the calcaneus and talus, and “Lisfranc’s Joint,” formed by a combination of all the tarsometatarsal joints. Both of these joints were initially identified as sites for surgical amputations and were not based on any presumed function. This study investigates the utility of these composite joints as sites of foot motion for humans and for some non‐human primates.

Data were drawn from 3D kinematic evaluations of the cadaveric feet of 12 humans, 11 chimpanzees, and 11 baboons. Data were collected in response to an anterior‐posterior and medial‐lateral driving motion of the leg over the foot. Data were derived from rigid cluster tracking of individual foot bones during an anterior‐posterior motion of the leg, typically associated with dorsiflexion‐plantarflexion, and a medial‐lateral leg motion, associated with inversion‐eversion and/or supination‐pronation. Data were analyzed using the Functional Alignment procedure to derive the orientation of axes of rotation for the involved joints.

Results show that the axis orientation of Chopart’s Joint is not a good compromise between the very different motions of the talonavicular and calcaneocuboid joints in any primate. This observation applies to results drawn from both anterior‐posterior and medial‐lateral driving motions. The rotational axis of Lisfranc’s Joint in the different primates is also quite divergent from the individual tarsometatarsal joint axes when responding to the anterior‐posterior driving action, but the axis is more parallel to those of the tarsometatarsal joints during the medial‐lateral driving action. However, it should be noted that the joint axes of the individual tarsometatarsal joints are almost identical, while the Lisfranc’s Joint axis stands apart.

These results show that the individual joint actions are more complicated than their composite forms expressed as Chopart’s or Lisfranc’s joints. The concept of single “transverse tarsal” joint may not be functionally justified, within the human animal or as a basis for comparison of humans and non‐human primates. Researchers should reassess how well these traditional joint concepts apply to their specific questions of foot biomechanics.

The author conveys his respect and gratitude to the persons whose remains are associated with this project.
Delineating the role of gldcin nephron patterning during kidney development
Authors: Weaver Nicole , Wingert Rebecca
Published: May 2022

Glycine is a simple amino acid that is vital to the proper functioning of the body, but its roles during ontogeny are not well understood. Glycine levels are precisely regulated through the glycine cleavage system (GCS), a complex molecular machine that produces one‐carbon units for later metabolism and folate production. Elevated glycine levels due to congenital mutations in GCS components, such as glycine dehydrogenase (gldc), cause devastating human birth defects and the rare disease nonketotic hyperglycinemia (NKH). NKH patients suffer from pleiotropic symptoms including seizures, apnea, lethargy, severe mental retardation, and early death; therefore, it is imperative to elucidate the downstream pathological mechanisms of glycine accumulation, which are to date largely unknown. Our lab, and others, have recently reported gldcdeficiency and glycine addition cause developmental changes in various tissues. Here, we interrogate the role of gldcin renal ontogeny. Whole mount in situ hybridization (WISH) revealed that gldc transcripts were highly expressed in multiple tissues, including the central nervous system and embryonic kidney, recapitulating both mouse and human expression studies. We found that formation of nephron cell populations in the kidney was disrupted in gldcdeficient and glycine treated embryos, where the distal early (DE) segment was increased at the expense of the distal late (DL) segment. These alterations led us to hypothesize that gldc is essential for distal segment patterning, a process that is regulated by interplay between the Iroquois (irx) transcription factors and transcription factor AP‐2a (tfap2a). To test this hypothesis, we have begun to analyze the spatiotemporal expression domains of irx3b and irx1a, which are conserved regulators of intermediate and distal segment development. Using WISH, we found that gldcdeficient and glycine treated animals exhibited an increase in the expression domain of irx1a, coinciding with the changes in DE specific solute transporter gene expression patterns. Taken together, these studies indicate that gldc has essential roles in regulating segment pattern during distal nephron development.
Chemogenetic activation of glutamatergic preBötzinger Complex neurons increases breathing in mice
Authors: Parzei Natalka , Scarpellini Carolina , Montandon Gaspard
Published: May 2022

Objective

Respiratory rhythm is generated by complex neural circuits in the medulla. At the core of these circuits is the preBötzinger Complex (preBötC), a collection of cells generating respiratory rhythm in the ventral part of the medulla. In addition to its role in generating respiratory rhythm, the preBötC also plays a significant role in opioid‐induced respiratory depression. The preBötC is made up of a heterogenous group of neurons, with a large portion being glutamatergic and expressing µ‐opioid receptors. A marker for these glutamatergic neurons is vesicular glutamate transporter 2 (vGLUT2). Here we propose that targeting vGLUT2‐expressing preBötC neurons using chemogenetics can stimulate respiratory rhythm and potentially alleviate opioid‐induced respiratory depression.

Hypothesis

Activation of vGLUT2 preBötC neurons stimulates breathing and alleviates respiratory depression by fentanyl in mice.

Methods

Using a cre‐lox recombination approach, we expressed the excitatory hM3Dq (a modified version of the excitatory M3 muscarinic receptor) into vGLUT2 preBötC neurons. To this aim, we injected into the preBötC recombinant adeno‐associated virus transcriptionally activated by Cre‐recombinase containing hM3Dq and mCherry DNA flanked by lox sites in vglut2‐IRES‐Cre male mice (Jackson Labs). Four weeks after adeno‐associated virus, mice were anesthetized with isoflurane and respiratory activity was measured through electrodes implanted into the diaphragm and the genioglossus muscle. Mice were given consecutive intramuscular injections of saline and the hM3Dq ligand, clozapine‐N‐oxide (CNO; 0.5 and 1 mg/kg), while respiratory responses were monitored. Brains were collected for histological analysis with expression of hM3Dq determined by expression of mCherry.

Results

Injection of 0.5mg/kg CNO elicited a 24.55% increase in respiratory rate 8 minutes following CNO injection. Injection of 1mg/kg CNO destabilized breathing within 6‐25 minutes following injection. Histology confirmed expression of mCherry in the region of the preBötC. Further studies will determine whether stimulation of vGLUT2 preBötC neurons can prevent or reverse respiratory rate depression elicited by fentanyl.

Conclusions

Our preliminary data showed that stimulation of glutamatergic preBötC neurons can increase respiratory rate in anesthetized conditions. Further studies will determine whether stimulation of glutamatergic preBötC cells also increases respiratory rate in freely‐behaving mice and whether the glutamatergic preBötC neurons are viable targets for the development of preventive drug therapies for respiratory depression during opioid overdose.
Sex‐Dependent Changes in Vascular Function in Adult Rats Following Prenatal Exposure to Methamphetamine
Authors: Chavva Hasitha , Belcher Adam M. , Brazeau Daniel A. , Rorabaugh Boyd R.
Published: May 2022

Background

Prenatal exposure to central nervous system stimulants such as cocaine, nicotine, and caffeine alters cardiovascular function in adult offspring. Methamphetamine use during pregnancy is associated with negative consequences in the offspring. However, most studies of methamphetamine use during pregnancy have focused on behavioral and neurological outcomes. Relatively little is known regarding the impact of prenatal methamphetamine exposure on the adult cardiovascular system. This study examined the hypothesis that methamphetamine use during pregnancy alters contractile function of the vasculature in the adult offspring. We also investigated the role of perivascular adipose tissue (PVAT) in methamphetamine‐induced changes in vascular function.

Methods

Pregnant female rats received daily injections of saline or methamphetamine (5 mg/kg) throughout gestation. Agonist‐induced contraction and relaxation responses were measured in aortas of 5 month old offspring in the presence and absence of perivascular adipose tissue.

Results

Prenatal methamphetamine significantly attenuated acetylcholine‐induced relaxation in male (but not female) aortas when PVAT remained intact. However, prenatal methamphetamine had no impact on acetylcholine‐induced relaxation when PVAT was removed. Nitroprusside‐induced relaxation was unaffected by prenatal methamphetamine. Prenatal exposure to methamphetamine had no impact on acetylcholine‐induced relaxation in third order mesenteric arteries of male or female offspring regardless of the presence of PVAT. Angiotensin II‐induced contractile responses were significantly potentiated in male (but not female) aortas regardless of the presence of PVAT. This effect was abolished by L‐Nitro arginine methyl ester (L‐NAME). Contractile responses to phenylephrine and serotonin were unaffected in both male and female aortas. Basal blood pressure in adult male and female offspring was also unaffected by prenatal exposure to methamphetamine.

Conclusions

Prenatal exposure to methamphetamine sex‐dependently alters PVAT function in the aorta. Methamphetamine also enhances angiotensin II‐induced contraction through a mechanism that involves suppression of nitric oxide signaling. These data provide evidence that methamphetamine use during pregnancy induces sex‐dependent changes in the vasculature that may increase the risk of cardiovascular disease in adult offspring.
Probing the Activity of Mitragyna Speciosa (Kratom) Alkaloids at Serotonin G Protein‐Coupled Receptors
Authors: Chen Yiming , McCurdy Christopher , Mottinelli Marco , Canal Clinton
Published: May 2022

The nation’s persistent opioid epidemic requires innovative treatment interventions. Mitragyna speciosa, or kratom, is an alkaloid‐containing tropical plant that has emerged as a potential opioid substitute therapy in recent decades. There are, however, no FDA‐approved uses for kratom, and scientists are actively engaged to elucidate the potential therapeutic benefits and harmful effects of kratom. Studies of kratom alkaloids have mainly focused on their opioid receptor activity, but emerging data show kratom has physiologically‐relevant activity at other biological targets. We recently reported that two kratom alkaloids prevalent in leaves of the kratom plant, speciogynine and paynantheine, bind to serotonin (5‐HT) 5‐HT1ARs and 5‐HT2BRs with affinities (Ki) less ≤100 nM and that their 9‐O‐desmethyl metabolites are efficacious agonists at 5‐HT1ARs (León et al., 2021 PMID: 34467758). We are undertaking studies to evaluate the pharmacology of the most prevalent alkaloids found in kratom leaves at each of the genetically‐encoded 5‐HT G protein‐coupled receptors (GPCRs). To further elucidate 5‐HTR G‐protein transduction pathways modulated by kratom alkaloids, we are utilizing the TRUPATH biosensor platform. By evaluating the potency and efficacy of kratom alkaloids to modulate the activity of unique G alpha subtypes linked to 5‐HTRs, we will provide fundamental 5‐HTR pharmacological characteristics of kratom alkaloids. The 5‐HT2BR is a crucial target for drug safety profiling since activation of this receptor can lead to cardiac valvulopathy. In addition, we are testing kratom alkaloids with an appreciable 5‐HT2BR affinity for their potential mitogenic activity in HEK cells utilizing [3H]thymidine incorporation. This research will provide crucial information about kratom’s pharmacological profile, independent of opioid receptors, that may contribute to its physiological effects.
The role of satellite cell derived TRIM28 in mechanical loading‐induced and injury‐induced myogenesis
Authors: Lin Kuan‐Hung , Lemens Jake , Torbey Melissa , Steinert Nathaniel , Hornberger Troy
Published: May 2022

Using a global phosphoproteomics‐based approach, we discovered that mechanical loading leads to a very robust increase in the phosphorylation of the S473 residue on TRIM28. Immunohistochemical analysis also revealed that the increase in TRIM28(S473) phosphorylation predominantly occurs within the myonuclei and satellite cells. The alteration in satellite cells was particularly intriguing because satellite cells function as muscle stem cells that can become activated in response to stimuli such as mechanical loading and injury. Once activated, satellite cells can undergo myogenesis which leads to the myonuclear accretion or the generation of new myofibers. Of note, many studies have reported that satellite cells are necessary for the mechanical loading‐induced growth of pre‐existing myofibers, as well as the formation of new myofibers that occur in response to injury. Furthermore, it has been reported that phosphorylation of the S473 residue on TRIM28 can unleash the transcriptional activity of MyoD and Mef2 (two key transcription factors that drive satellite cell‐mediated myogenesis). Inspired by these points, we generated satellite cell specific and tamoxifen‐inducible TRIM28 knockout mice and then used these mice to discover that satellite cell derived TRIM28 is not only required for the normal myonuclear accretion that occurs in response to mechanical loading, but also the regeneration of myofibers following an injury. Furthermore, in vitro analyses revealed that the knockdown of TRIM28 leads to a fusion defect in primary myoblast. Taken together, these findings unravel a novel role of satellite cell‐derived TRIM28 in mechanical loading‐induced and injury induced myogenesis.
Connecting the Dots: Students’ Mental Organization and Storage of Biochemistry Visual Literacy Skills
Authors: Terrell Cassidy R. , Aguirre Lopez Abner , Bobick Natalie A. , Erickson Amanda , Fondie Cole R. , Lawrence Andrea E. , Prat‐Resina Xavier
Published: May 2022

Undergraduate molecular life science curricula rely on a variety of abstract visual representations to convey information. Intentional development of undergraduate students’ visual literacy skills has the potential to increase conceptual understanding while also decreasing cognitive load. There is little existing research that assesses how students interpret and store biochemical information and representations in their long‐term memory. Moreover, the number of validated instruments for measuring visual literacy is limited. Studies performed with undergraduate chemistry students measured students’ structural knowledge, or schema, of topics by asking them to rank the relatedness of words/phrases. Our study aims to develop a valid assessment tool that measures participants' schema of biochemistry visual literacy skills by asking them to rank the relatedness of biochemical representations instead of words/phrases. We created four surveys to evaluate vertical and horizontal translation visual literacy skills. With the use of Pathfinder, we analyzed the schema of undergraduate students with variable knowledge in biochemistry at four universities against an expert referentnetwork. Preliminary results also assess if pedagogical strategies and course instructional modalities impact student’s schema. The characterization of representational schema held by students and experts could aid the development of curricular materials for optimal learning and retention of information in the molecular life sciences.
Sex Differences in Estimates of Cardiac Autonomic Function Using Time Domain based Method of Heart Rate Variability: Effects of Oral Capsaicin
Authors: Zaleski Kendall S. , Gyampo Abena , Lora Brian , Tomasi Tawn , Lynch Meaghan , Giuriato Gaia , Basso Emma , Finegan Emma , Schickler Jack , Venturelli Massimo , Ives Stephen J.
Published: May 2022

Heart rate variability (HRV) estimates autonomic nervous system (ANS) influence on the heart and is sex‐specific. Sensory afferents exhibit sex‐specificity; although, there is a paucity of data on the potential effects of Capsaicin, an agonist for transient receptor potential vanilloid channel‐1 (TRPV1), on cardiac ANS activity and if the effect is sex‐dependent. Given the predictive nature of HRV on risk of developing hypertension, understanding the sex differences in factors governing HRV is paramount.

PURPOSE

Therefore, this study sought to determine the sex‐specificity in the effect of capsaicin on cardiac autonomic function estimated through HRV. It was hypothesized that females would have lower HRV than the age‐matched males and that capsaicin could attenuate these sex differences.

METHODS

HRV was measured in 38 young males (M: n=25) and females (F: n=13), in a blinded crossover design, after acute ingestion of placebo or capsaicin capsules. Resting measurements of HR, RR interval, root mean square of successive differences (RMSSD), natural log‐transformed RMSSD (LnRMSSD), standard deviation of n‐n intervals (SDNN), number of pairs of successive n‐n intervals that differ by more than 50 msec (NN50), and percent NN50 to total n‐n intervals (PNN50) were obtained using standard techniques.

RESULTS

Under placebo, males had significantly lower minimum HR (M: 49±9.7 vs. F: 58±16 beats/min, p=0.038, d=‐0.738) and significantly higher NN50 (M: 141±118 vs. F: 33±23, p=0.003, d=‐0.129) than females. There was a main effect of sex on HR (M: 59±9.3 vs. F: 65±12 beats/min, p=0.036, η2=0.098), minimum HR (M: 47±8.3 vs. F: 56±12 beats/min, p=0.014, η2=0.124), and NN50 (M: 177±143 vs. F: 29±17, p<0.001, η2=0.249). There was a significant interaction of sex and treatment (p=0.02, η2=0.027) for RMSSD, where males increased (Placebo: 78±55 vs. Capsaicin: 91±64 ms), and females decreased (Placebo: 105±83 vs. Capsaicin 76±43 ms).

CONCLUSION

This study recapitulates previously documented sex differences in HR and HRV. Acute ingestion of capsaicin increased RMSSD in men, but decreased RMSSD in women, suggesting a sexual dimorphism in parasympathetic response, perhaps due to differences in TRPV1‐sensitive afferents or sensitivity. The physiological ramifications of these findings, specifically in the regulation of blood pressure and ultimately cardiovascular disease risk remain to be explored, especially in the transition to menopause in women.