Open Access Publications

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Open access publications by faculty, postdocs, and graduate students in the Department of Biological Sciences

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Adseverin, an actin-binding protein, modulates hypertrophic chondrocyte differentiation and osteoarthritis progression
(Science Advances, 2023-08-04) Chan, Byron; Glogauer, Michael; Wang, Yongqiang; Wrana, Jeffrey; Chan, Kin; Beier, Frank; Bali, Supinder; Hinz, Boris; Parreno, Justin; Ashraf, Sajjad; Kandel, Rita
In osteoarthritis (OA), a disease characterized by progressive articular cartilage degradation and calcification, the articular chondrocyte phenotype changes and this correlates with actin cytoskeleton alterations suggesting that it regulates gene expression essential for proper phenotype. This study reports that OA is associated with the loss of adseverin, an actin capping and severing protein. Adseverin deletion (Adseverin−/−) in mice compromised articular chondrocyte function, by reducing F-actin and aggrecan expression and increasing apoptosis, Indian hedgehog, Runx2, MMP13, and collagen type X expression, and cell proliferation. This led to stiffer cartilage and decreased hyaline and increased calcified cartilage thickness. Together, these changes predisposed the articular cartilage to enhanced OA severity in Adseverin−/− mice who underwent surgical induction of OA. Adseverin−/− chondrocyte RNA sequencing and in vitro studies together suggests that adseverin modulates cell viability and prevents mineralization. Thus, adseverin maintains articular chondrocyte phenotype and cartilage tissue homeostasis by preventing progression to hypertrophic differentiation in vivo. Adseverin may be chondroprotective and a potential therapeutic target.
Association of Behavioral and Clinical Risk Factors With Cataract: A Two-Sample Mendelian Randomization Study
(Investigative Ophthalmology & Visual Science, 2023-07) Jiang, Chen; Melles, Ronald B.; Sangani, Poorab; Hoffmann, Thomas J.; Hysi, Pirro G.; Glymour, M. Maria; Jorgenson, Eric; Lachke, Salil A.; Choquet, Hélène
Purpose: To investigate the association of genetically determined primary open-angle glaucoma (POAG), myopic refractive error (RE), type 2 diabetes (T2D), blood pressure (BP), body mass index (BMI), cigarette smoking, and alcohol consumption with the risk of age-related cataract. Methods: To assess potential causal effects of clinical or behavioral factors on cataract risk, we conducted two-sample Mendelian randomization analyses. Genetic instruments, based on common genetic variants associated with risk factors at genome-wide significance (P < 5 × 10−8), were derived from published genome-wide association studies (GWAS). For age-related cataract, we used GWAS summary statistics from our previous GWAS conducted in the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (28,092 cataract cases and 50,487 controls; all non-Hispanic whites) or in the UK Biobank (31,852 cataract cases and 428,084 controls; all European-descent individuals). We used the inverse-variance weighted (IVW) method as our primary source of Mendelian randomization estimates and conducted common sensitivity analyses. Results: We found that genetically determined POAG and mean spherical equivalent RE were significantly associated with cataract risk (IVW model: odds ratio [OR] = 1.04; 95% confidence interval [CI], 1.01–1.08; P = 0.018; per diopter more hyperopic: OR = 0.92; 95% CI, 0.89–0.93; P = 6.51 × 10−13, respectively). In contrast, genetically determined T2D, BP, BMI, cigarette smoking, or alcohol consumption were not associated with cataract risk (P > 0.05). Conclusions: Our results provide evidence that genetic risks for POAG and myopia may be causal risk factors for age-related cataract. These results are consistent with previous observational studies reporting associations of myopia with cataract risk. This information may support population cataract risk stratification and screening strategies.
Matrix Degradability Contributes to the Development of Salivary Gland Progenitor Cells with Secretory Functions
(ACS Applied Materials and Interfaces, 2023-07-12) Metkari, Apoorva S.; Fowler, Eric W.; Witt, Robert L.; Jia, Xinqiao
Synthetic matrices that are cytocompatible, cell adhesive, and cell responsive are needed for the engineering of implantable, secretory salivary gland constructs to treat radiation induced xerostomia or dry mouth. Here, taking advantage of the bioorthogonality of the Michael-type addition reaction, hydrogels with comparable stiffness but varying degrees of degradability (100% degradable, 100DEG; 50% degradable, 50DEG; and nondegradable, 0DEG) by cell-secreted matrix metalloproteases (MMPs) were synthesized using thiolated HA (HA-SH), maleimide (MI)-conjugated integrin-binding peptide (RGD-MI), and MI-functionalized peptide cross-linkers that are protease degradable (GIW-bisMI) or nondegradable (GIQ-bisMI). Organized multicellular structures developed readily in all hydrogels from dispersed primary human salivary gland stem cells (hS/PCs). As the matrix became progressively degradable, cells proliferated more readily, and the multicellular structures became larger, less spherical, and more lobular. Immunocytochemical analysis showed positive staining for stem/progenitor cell markers CD44 and keratin 5 (K5) in all three types of cultures and positive staining for the acinar marker α-amylase under 50DEG and 100DEG conditions. Quantitatively at the mRNA level, the expression levels of key stem/progenitor markers KIT, KRT5, and ETV4/5 were significantly increased in the degradable gels as compared to the nondegradable counterparts. Western blot analyses revealed that imparting matrix degradation led to >3.8-fold increase in KIT expression by day 15. The MMP-degradable hydrogels also promoted the development of a secretary phenotype, as evidenced by the upregulation of acinar markers α-amylase (AMY), aquaporin-5 (AQP5), and sodium-potassium chloride cotransporter 1 (SLC12A2). Collectively, we show that cell-mediated matrix remodeling is necessary for the development of regenerative pro-acinar progenitor cells from hS/PCs.
A Review of IsomiRs in Colorectal Cancer
(Non-Coding RNA, 2023-06-07) Lausten, Molly A.; Boman, Bruce M.
As advancements in sequencing technology rapidly continue to develop, a new classification of microRNAs has occurred with the discovery of isomiRs, which are relatively common microRNAs with sequence variations compared to their established template microRNAs. This review article seeks to compile all known information about isomiRs in colorectal cancer (CRC), which has not, to our knowledge, been gathered previously to any great extent. A brief overview is given of the history of microRNAs, their implications in colon cancer, the canonical pathway of biogenesis and isomiR classification. This is followed by a comprehensive review of the literature that is available on microRNA isoforms in CRC. The information on isomiRs presented herein shows that isomiRs hold great promise for translation into new diagnostics and therapeutics in clinical medicine.
NhaR, LeuO, and H-NS Are Part of an Expanded Regulatory Network for Ectoine Biosynthesis Expression
(Applied and Environmental Microbiology, 2023-06-06) Boas Lichty, Katherine E. Boas; Gregory, Gwendolyn J.; Boyd, E. Fidelma
Bacteria accumulate compatible solutes to maintain cellular turgor pressure when exposed to high salinity. In the marine halophile Vibrio parahaemolyticus, the compatible solute ectoine is biosynthesized de novo, which is energetically more costly than uptake; therefore, tight regulation is required. To uncover novel regulators of the ectoine biosynthesis ectABC-asp_ect operon, a DNA affinity pulldown of proteins interacting with the ectABC-asp_ect regulatory region was performed. Mass spectrometry analysis identified, among others, 3 regulators: LeuO, NhaR, and the nucleoid associated protein H-NS. In-frame non-polar deletions were made for each gene and PectA-gfp promoter reporter assays were performed in exponential and stationary phase cells. PectA-gfp expression was significantly repressed in the ΔleuO mutant and significantly induced in the ΔnhaR mutant compared to wild type, suggesting positive and negative regulation, respectively. In the Δhns mutant, PectA-gfp showed increased expression in exponential phase cells, but no change compared to wild type in stationary phase cells. To examine whether H-NS interacts with LeuO or NhaR at the ectoine regulatory region, double deletion mutants were created. In a ΔleuO/Δhns mutant, PectA-gfp showed reduced expression, but significantly more than ΔleuO, suggesting H-NS and LeuO interact to regulate ectoine expression. However, ΔnhaR/Δhns had no additional effect compared to ΔnhaR, suggesting NhaR regulation is independent of H-NS. To examine leuO regulation further, a PleuO-gfp reporter analysis was examined that showed significantly increased expression in the ΔleuO, Δhns, and ΔleuO/Δhns mutants compared to wild type, indicating both are repressors. Growth pattern analysis of the mutants in M9G 6%NaCl showed growth defects compared to wild type, indicating that these regulators play an important physiological role in salinity stress tolerance outside of regulating ectoine biosynthesis gene expression. IMPORTANCE Ectoine is a commercially used compatible solute that acts as a biomolecule stabilizer because of its additional role as a chemical chaperone. A better understanding of how the ectoine biosynthetic pathway is regulated in natural bacterial producers can be used to increase efficient industrial production. The de novo biosynthesis of ectoine is essential for bacteria to survive osmotic stress when exogenous compatible solutes are absent. This study identified LeuO as a positive regulator and NhaR as a negative regulator of ectoine biosynthesis and showed that, similar to enteric species, LeuO is an anti-silencer of H-NS. In addition, defects in growth in high salinity among all the mutants suggest that these regulators play a broader role in the osmotic stress response beyond ectoine biosynthesis regulation.
Nonmuscle Myosin IIA Regulates the Precise Alignment of Hexagonal Eye Lens Epithelial Cells During Fiber Cell Formation and Differentiation
(Investigative Ophthalmology & Visual Science, 2023-04-18) Islam, Sadia T.; Cheng, Catherine; Parreno, Justin; Fowler, Velia M.
Purpose: Epithelial cells in the equatorial region of the ocular lens undergo a remarkable transition from randomly packed cells into precisely aligned and hexagon-shaped cells organized into meridional rows. We investigated the function of nonmuscle myosin IIA (encoded by Myh9) in regulating equatorial epithelial cell alignment to form meridional rows during secondary fiber cell morphogenesis. Methods: We used genetic knock-in mice to study a common human Myh9 mutation, E1841K, in the rod domain. The E1841K mutation disrupts bipolar filament assembly. Lens shape, clarity, and stiffness were evaluated, and Western blots were used to determine the level of normal and mutant myosins. Cryosections and lens whole mounts were stained and imaged by confocal microscopy to investigate cell shape and organization. Results: We observed no obvious changes in lens size, shape, and biomechanical properties (stiffness and resilience) between the control and nonmuscle myosin IIA–E1841K mutant mice at 2 months of age. Surprisingly, we found misalignment and disorder of fiber cells in heterozygous and homozygous mutant lenses. Further analysis revealed misshapen equatorial epithelial cells that cause disorientation of the meridional rows before fiber cell differentiation in homozygous mutant lenses. Conclusions: Our data indicate that nonmuscle myosin IIA bipolar filament assembly is required for the precise alignment of the meridional rows at the lens equator and that the organization of lens fiber cells depends on the proper patterning of meridional row epithelial cells. These data also suggest that lens fiber cell organization and a hexagonal shape are not required for normal lens size, shape transparency, or biomechanical properties.
Innate immune pathway modulator screen identifies STING pathway activation as a strategy to inhibit multiple families of arbo and respiratory viruses
(Cell Reports Medicine, 2023-05-16) Garcia, Gustavo Jr.; Irudayam, Joseph Ignatius; Jeyachandran, Arjit Vijey; Dubey, Swati; Chang, Christina; Castillo Cario, Sebastian; Price, Nate; Arumugam, Sathya; Marquez, Angelica L.; Shah, Aayushi; Fanaei, Amir; Chakravarty, Nikhil; Joshi, Shantanu; Sinha, Sanjeev; French, Samuel W.; Parcells, Mark S.; Ramaiah, Arunachalam; Arumugaswami, Vaithilingaraja
Highlights: • Screen identifies innate immune agonists blocking multiple families of RNA viruses • Dectin-1 and cGAS-STING pathway agonists exhibit broader antiviral activity • STING activator cAIMP blocks ZIKV, WNV, CHIKV, EV-D68, and SARS-CoV-2 infections • cAIMP provides protection against CHIKV-mediated chronic arthritis in mouse model Summary: RNA viruses continue to remain a threat for potential pandemics due to their rapid evolution. Potentiating host antiviral pathways to prevent or limit viral infections is a promising strategy. Thus, by testing a library of innate immune agonists targeting pathogen recognition receptors, we observe that Toll-like receptor 3 (TLR3), stimulator of interferon genes (STING), TLR8, and Dectin-1 ligands inhibit arboviruses, Chikungunya virus (CHIKV), West Nile virus, and Zika virus to varying degrees. STING agonists (cAIMP, diABZI, and 2′,3′-cGAMP) and Dectin-1 agonist scleroglucan demonstrate the most potent, broad-spectrum antiviral function. Furthermore, STING agonists inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and enterovirus-D68 (EV-D68) infection in cardiomyocytes. Transcriptome analysis reveals that cAIMP treatment rescue cells from CHIKV-induced dysregulation of cell repair, immune, and metabolic pathways. In addition, cAIMP provides protection against CHIKV in a chronic CHIKV-arthritis mouse model. Our study describes innate immune signaling circuits crucial for RNA virus replication and identifies broad-spectrum antivirals effective against multiple families of pandemic potential RNA viruses. Graphical abstract available at: https://doi.org/10.1016/j.xcrm.2023.101024
Clinicians’ Perspectives on Proactive Patient Safety Behaviors in the Perioperative Environment
(Jama Network Open, 2023-04-11) Duffy, Caoimhe; Menon, Neil; Horak, David; Bass, Geoffrey D.; Talwar, Ruchika; Lorenzi, Cara; Vo, Christina Taing; Chiang, Chienhui; Ziemba, Justin B.
Importance The perioperative environment is hazardous, but patients remain safe with a successful outcome during their care due to staff adaptability and resiliency. The behaviors that support this adaptability and resilience have yet to be defined or analyzed. One Safe Act (OSA), a tool and activity developed to capture self-reported proactive safety behaviors that staff use in their daily practice to promote individual and team-based safe patient care, may allow for improved definition and analysis of these behaviors. Objective To thematically analyze staff behaviors using OSA to understand what may serve as the basis for proactive safety in the perioperative environment. Design, Setting, and Participants This qualitative thematic analysis included a convenience sample of perioperative staff at a single-center, tertiary care academic medical center who participated in an OSA activity during a 6-month period in 2021. All perioperative staff were eligible for inclusion. A combined deductive approach, based on a human factor analysis and classification framework, as well as an inductive approach was used to develop themes and analyze the self-reported staff safety behaviors. Exposures Those selected to participate were asked to join an OSA activity, which was conducted in-person by a facilitator. Participants were to self-reflect about their OSA (proactive safety behavior) and record their experience as free text in an online survey tool. Main Outcome and Measures The primary outcome was the development and application of a set of themes to describe proactive safety behaviors in the perioperative environment. Results A total of 140 participants (33 nurses [23.6%] and 18 trainee physicians [12.9%]), which represented 21.3% of the 657 total perioperative department full-time staff, described 147 behaviors. A total of 8 non–mutually exclusive themes emerged with the following categories and frequency of behaviors: (1) routine-based adaptations (46 responses [31%]); (2) resource availability and assessment adaptations (31 responses [21%]); (3) communication and coordination adaptation (23 responses [16%]); (4) environmental ergonomics adaptation (17 responses [12%]); (5) situational awareness adaptation (12 responses [8%]); (6) personal or team readiness adaptation (8 responses [5%]); (7) education adaptation (5 responses [3%]); and (8) social awareness adaptation (5 responses [3%]). Conclusions and Relevance The OSA activity elicited and captured proactive safety behaviors performed by staff. A set of behavioral themes were identified that may serve as the basis for individual practices of resilience and adaptability that promote patient safety.
The actin bundling protein Fascin is important for proper early development in Strongylocentrotus purpuratus embryos
(microPublication Biology, 2023-03-21) Testa, Michael D.; Remsburg, Carolyn M.; Song, Jia L.
Fascin is a conserved protein that has been shown to modulate the cytoskeleton. Its role in early development remains unclear. After fertilization, embryos undergo rapid cell divisions, requiring the precise regulation of cytoskeleton to segregate chromosomes. Results indicate that Fascin is in the cell cortex, enriched in the perinuclear region of non-dividing blastomeres and on the mitotic spindle of dividing blastomeres of the early embryo. Loss-of-function of Fascin leads to a significant developmental delay or arrest, indicating that Fascin is important for proper early embryonic development.
The v8-10 variant isoform of CD44 is selectively expressed in the normal human colonic stem cell niche and frequently is overexpressed in colon carcinomas during tumor development
(Cancer Biology & Therapy, 2023-04-02) Boman, Bruce M.; Viswanathan, Vignesh; Faceya, Caroline O. B.; Fields, Jeremy Z.; Stave, James W.
CD44 protein and its variant isoforms are expressed in cancer stem cells (CSCs), and various CD44 isoforms can have different functional roles in cells. Our goal was to investigate how different CD44 isoforms contribute to the emergence of stem cell (SC) overpopulation that drives colorectal cancer (CRC) development. Specific CD44 variant isoforms are selectively expressed in normal colonic SCs and become overexpressed in CRCs during tumor development. We created a unique panel of anti-CD44 rabbit genomic antibodies to 16 specific epitopes that span the entire length of the CD44 molecule. Our panel was used to comprehensively investigate the expression of different CD44 isoforms in matched pairs (n = 10) of malignant colonic tissue and adjacent normal mucosa, using two (IHC & IF) immunostaining approaches. We found that: i) CD44v8–10 is selectively expressed in the normal human colonic SC niche; ii) CD44v8–10 is co-expressed with the SC markers ALDH1 and LGR5 in normal and malignant colon tissues; iii) colon carcinoma tissues frequently (80%) stain for CD44v8–10 while staining for CD44v6 was less frequent (40%). Given that CD44v8–10 expression is restricted to cells in the normal human colonic SC niche and CD44v8–10 expression progressively increases during CRC development, CD44v8–10 expression likely contributes to the SC overpopulation that drives the development and growth of colon cancers. Since the CD44 variant v8–10 epitope is located on CD44’s extracellular region, it offers great promise for targeted anti-CSC treatment approaches.
Dynamic bioinspired coculture model for probing ER+ breast cancer dormancy in the bone marrow niche
(Science Advances, 2023-03-08) Pradhan, Lina; Moore, DeVonte; Ovadia, Elisa M.; Swedzinski, Samantha L.; Cossette, Travis; Sikes, Robert A.; van Golen, Kenneth; Kloxin, April M.
Late recurrences of breast cancer are hypothesized to arise from disseminated tumor cells (DTCs) that reactivate after dormancy and occur most frequently with estrogen receptor–positive (ER+) breast cancer cells (BCCs) in bone marrow (BM). Interactions between the BM niche and BCCs are thought to play a pivotal role in recurrence, and relevant model systems are needed for mechanistic insights and improved treatments. We examined dormant DTCs in vivo and observed DTCs near bone lining cells and exhibiting autophagy. To study underlying cell-cell interactions, we established a well-defined, bioinspired dynamic indirect coculture model of ER+ BCCs with BM niche cells, human mesenchymal stem cells (hMSCs) and fetal osteoblasts (hFOBs). hMSCs promoted BCC growth, whereas hFOBs promoted dormancy and autophagy, regulated in part by tumor necrosis factor–α and monocyte chemoattractant protein 1 receptor signaling. This dormancy was reversible by dynamically changing the microenvironment or inhibiting autophagy, presenting further opportunities for mechanistic and targeting studies to prevent late recurrence.
Limiting Mrs2-dependent mitochondrial Mg2+ uptake induces metabolic programming in prolonged dietary stress
(Cell Reports, 2023-03-28) Madaris, Travis R.; Venkatesan, Manigandan; Maity, Soumya; Stein, Miriam C.; Vishnu, Neelanjan; Venkateswaran, Mridula K.; Davis, James G.; Ramachandran, Karthik; Uthayabalan, Sukanthathulse; Allen, Cristel; Osidele, Ayodeji; Stanley, Kristen; Bigham, Nicholas P.; Bakewell, Terry M.; Narkunan, Melanie; Le, Amy; Karanam, Varsha; Li, Kang; Mhapankar, Aum; Norton, Luke; Ross, Jean; Aslam, M. Imran; Reeves, W. Brian; Singh, Brij B.; Caplan, Jeffrey; Wilson, Justin J.; Stathopulos, Peter B.; Baur, Joseph A.; Madesh, Muniswamy
Highlights: • Mitochondrial Mg2+ channel Mrs2 rheostats MCU Ca2+ signals to maintain bioenergetic circuit • DNL precursor and cellular Mg2+ chelator citrate curbs HIF1α signal and oxidative metabolism • Lowering mMg2+ mitigates prolonged dietary-stress-induced obesity and metabolic syndrome • Mrs2 channel blocker CPACC reduces lipid accumulation and promotes browning and weight loss Summary The most abundant cellular divalent cations, Mg2+ (mM) and Ca2+ (nM-μM), antagonistically regulate divergent metabolic pathways with several orders of magnitude affinity preference, but the physiological significance of this competition remains elusive. In mice consuming a Western diet, genetic ablation of the mitochondrial Mg2+ channel Mrs2 prevents weight gain, enhances mitochondrial activity, decreases fat accumulation in the liver, and causes prominent browning of white adipose. Mrs2 deficiency restrains citrate efflux from the mitochondria, making it unavailable to support de novo lipogenesis. As citrate is an endogenous Mg2+ chelator, this may represent an adaptive response to a perceived deficit of the cation. Transcriptional profiling of liver and white adipose reveals higher expression of genes involved in glycolysis, β-oxidation, thermogenesis, and HIF-1α-targets, in Mrs2−/− mice that are further enhanced under Western-diet-associated metabolic stress. Thus, lowering mMg2+ promotes metabolism and dampens diet-induced obesity and metabolic syndrome. Graphical abstract Available at: https://doi.org/10.1016/j.celrep.2023.112155
RNA localization to the mitotic spindle is essential for early development and is regulated by kinesin-1 and dynein
(Journal of Cell Science, 2023-03-06) Remsburg, Carolyn M.; Konrad, Kalin D.; Song, Jia L.
Mitosis is a fundamental and highly regulated process that acts to faithfully segregate chromosomes into two identical daughter cells. Localization of gene transcripts involved in mitosis to the mitotic spindle might be an evolutionarily conserved mechanism to ensure that mitosis occurs in a timely manner. We identified many RNA transcripts that encode proteins involved in mitosis localized at the mitotic spindles in dividing sea urchin embryos and mammalian cells. Disruption of microtubule polymerization, kinesin-1 or dynein results in lack of spindle localization of these transcripts in the sea urchin embryo. Furthermore, results indicate that the cytoplasmic polyadenylation element (CPE) within the 3′UTR of the Aurora B transcript, a recognition sequence for CPEB, is essential for RNA localization to the mitotic spindle in the sea urchin embryo. Blocking this sequence results in arrested development during early cleavage stages, suggesting that RNA localization to the mitotic spindle might be a regulatory mechanism of cell division that is important for early development.
Lens Epithelial Explants Treated with Vitreous Humor Undergo Alterations in Chromatin Landscape with Concurrent Activation of Genes Associated with Fiber Cell Differentiation and Innate Immune Response
(Cells, 2023-02-03) Upreti, Anil; Padula, Stephanie L.; Tangeman, Jared A.; Wagner, Brad D.; O’Connell, Michael J.; Jaquish, Tycho J.; Palko, Raye K.; Mantz, Courtney J.; Anand, Deepti; Lovicu, Frank J.; Lachke, Salil A.; Robinson, Michael L.
Lens epithelial explants are comprised of lens epithelial cells cultured in vitro on their native basement membrane, the lens capsule. Biologists have used lens epithelial explants to study many different cellular processes including lens fiber cell differentiation. In these studies, fiber differentiation is typically measured by cellular elongation and the expression of a few proteins characteristically expressed by lens fiber cells in situ. Chromatin and RNA was collected from lens epithelial explants cultured in either un-supplemented media or media containing 50% bovine vitreous humor for one or five days. Chromatin for ATAC-sequencing and RNA for RNA-sequencing was prepared from explants to assess regions of accessible chromatin and to quantitatively measure gene expression, respectively. Vitreous humor increased chromatin accessibility in promoter regions of genes associated with fiber differentiation and, surprisingly, an immune response, and this was associated with increased transcript levels for these genes. In contrast, vitreous had little effect on the accessibility of the genes highly expressed in the lens epithelium despite dramatic reductions in their mRNA transcripts. An unbiased analysis of differentially accessible regions revealed an enrichment of cis-regulatory motifs for RUNX, SOX and TEAD transcription factors that may drive differential gene expression in response to vitreous.
Mucopolysaccharidoses: Cellular Consequences of Glycosaminoglycans Accumulation and Potential Targets
(International Journal of Molecular Sciences, 2022-12-28) Leal, Andrés Felipe; Benincore-Flórez, Eliana; Rintz, Estera; Herreño-Pachón, Angélica María; Celik, Betul; Ago, Yasuhiko; Alméciga-Díaz, Carlos Javier; Tomatsu, Shunji
Mucopolysaccharidoses (MPSs) constitute a heterogeneous group of lysosomal storage disorders characterized by the lysosomal accumulation of glycosaminoglycans (GAGs). Although lysosomal dysfunction is mainly affected, several cellular organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and their related process are also impaired, leading to the activation of pathophysiological cascades. While supplying missing enzymes is the mainstream for the treatment of MPS, including enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), or gene therapy (GT), the use of modulators available to restore affected organelles for recovering cell homeostasis may be a simultaneous approach. This review summarizes the current knowledge about the cellular consequences of the lysosomal GAGs accumulation and discusses the use of potential modulators that can reestablish normal cell function beyond ERT-, HSCT-, or GT-based alternatives.
Self-Assembly, Self-Folding, and Origami: Comparative Design Principles
(Biomimetics, 2022-12-27) Jungck, John R.; Brittain, Stephen; Plante, Donald; Flynn, James
Self-assembly is usually considered a parallel process while self-folding and origami are usually considered to be serial processes. We believe that these distinctions do not hold in actual experiments. Based upon our experience with 4D printing, we have developed three additional hybrid classes: (1) templated-assisted (tethered) self-assembly: e.g., when RNA is bound to viral capsomeres, the subunits are constricted in their interactions to have aspects of self-folding as well; (2) self-folding can depend upon interactions with the environment; for example, a protein synthesized on a ribosome will fold as soon as peptides enter the intracellular environment in a serial process whereas if denatured complete proteins are put into solution, parallel folding can occur simultaneously; and, (3) in turbulent environments, chaotic conditions continuously alternate processes. We have examined the 43,380 Dürer nets of dodecahedra and 43,380 Dürer nets of icosahedra and their corresponding duals: Schlegel diagrams. In order to better understand models of self-assembly of viral capsids, we have used both geometric (radius of gyration, convex hulls, angles) and topological (vertex connections, leaves, spanning trees, cutting trees, and degree distributions) perspectives to develop design principles for 4D printing experiments. Which configurations fold most rapidly? Which configurations lead to complete polyhedra most of the time? By using Hamiltonian circuits of the vertices of Dürer nets and Eulerian paths of cutting trees of polyhedra unto Schlegel diagrams, we have been able to develop a systematic sampling procedure to explore the 86,760 configurations, models of a T1 viral capsid with 60 subunits and to test alternatives with 4D printing experiments, use of MagformsTM, and origami models to demonstrate via movies the five processes described above.
NeuroD1 localizes to the presumptive ganglia and gut of the sea urchin larvae
(microPublication Biology, 2022-11-15) Konrad, Kalin D.; Song, Jia L.
NeuroD1 is a transcription factor (TF) that plays a dual role in vertebrate neurogenesis and glucose homeostasis in the pancreas. We identified a NeuroD1 antibody developed against human that cross-reacts with the sea urchin NeuroD1. NeuroD1 protein localizes to the presumptive ganglia and neurofilament structures in the ciliary band of the sea urchin larvae. In addition, we also observed NeuroD1 in the perinuclear region in the sea urchin gut which is analogous to the mammalian pancreas. These results suggest that NeuroD1 may play an evolutionarily conserved role in the invertebrate sea urchin.
Megakaryocyte membrane-wrapped nanoparticles for targeted cargo delivery to hematopoietic stem and progenitor cells
(Bioengineering and Translational Medicine, 2022-11-29) Das, Samik; Harris, Jenna C.; Winter, Erica J.; Kao, Chen-Yuan; Day, Emily S.; Papoutsakis, Eleftherios Terry
Hematopoietic stem and progenitor cells (HSPCs) are desirable targets for gene therapy but are notoriously difficult to target and transfect. Existing viral vector-based delivery methods are not effective in HSPCs due to their cytotoxicity, limited HSPC uptake and lack of target specificity (tropism). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are attractive, nontoxic carriers that can encapsulate various cargo and enable its controlled release. To engineer PLGA NP tropism for HSPCs, megakaryocyte (Mk) membranes, which possess HSPC-targeting moieties, were extracted and wrapped around PLGA NPs, producing MkNPs. In vitro, fluorophore-labeled MkNPs are internalized by HSPCs within 24 h and were selectively taken up by HSPCs versus other physiologically related cell types. Using membranes from megakaryoblastic CHRF-288 cells containing the same HSPC-targeting moieties as Mks, CHRF-wrapped NPs (CHNPs) loaded with small interfering RNA facilitated efficient RNA interference upon delivery to HSPCs in vitro. HSPC targeting was conserved in vivo, as poly(ethylene glycol)–PLGA NPs wrapped in CHRF membranes specifically targeted and were taken up by murine bone marrow HSPCs following intravenous administration. These findings suggest that MkNPs and CHNPs are effective and promising vehicles for targeted cargo delivery to HSPCs.
Stress deprivation of tendon explants or Tpm3.1 inhibition in tendon cells reduces F-actin to promote a tendinosis-like phenotype
(Molecular Biology of the Cell, 2022-12-01) Inguito, Kameron L.; Schofield, Mandy M.; Faghri, Arya D.; Bloom, Ellen T.; Heino, Marissa; West, Valerie C.; Ebron, Karl Matthew M.; Elliot, Dawn M.; Parreno, Justin
Actin is a central mediator between mechanical force and cellular phenotype. In tendons, it is speculated that mechanical stress deprivation regulates gene expression by reducing filamentous (F)-actin. However, the mechanisms regulating tenocyte F-actin remain unclear. Tropomyosins (Tpms) are master regulators of F-actin. There are more than 40 Tpm isoforms, each having the unique capability to stabilize F-actin subpopulations. We investigated F-actin polymerization in stress-deprived tendons and tested the hypothesis that stress fiber–associated Tpm(s) stabilize F-actin to regulate cellular phenotype. Stress deprivation of mouse tail tendon down-regulated tenogenic and up-regulated protease (matrix metalloproteinase-3) mRNA levels. Concomitant with mRNA modulation were increases in G/F-actin, confirming reduced F-actin by tendon stress deprivation. To investigate the molecular regulation of F-actin, we identified that tail, Achilles, and plantaris tendons express three isoforms in common: Tpm1.6, 3.1, and 4.2. Tpm3.1 associates with F-actin in native and primary tenocytes. Tpm3.1 inhibition reduces F-actin, leading to decreases in tenogenic expression, increases in chondrogenic expression, and enhancement of protease expression in mouse and human tenocytes. These expression changes by Tpm3.1 inhibition are consistent with tendinosis progression. A further understanding of F-actin regulation in musculoskeletal cells could lead to new therapeutic interventions to prevent alterations in cellular phenotype during disease progression.
Coupling Novel Probes with Molecular Localization Microscopy Reveals Cell Wall Homeostatic Mechanisms in Staphylococcus aureus
(ACS Chemical Biology, 2022-11-22) Lund, Victoria A.; Gangotra, Haneesh; Zhao, Zhen; Sutton, Joshua A. F.; Wacnik, Katarzyna; DeMeester, Kristen; Liang, Hai; Santiago, Cintia; Grimes, Catherine Leimkuhler; Jones, Simon; Foster, Simon J.
Bacterial cell wall peptidoglycan is essential for viability, and its synthesis is targeted by antibiotics, including penicillin. To determine how peptidoglycan homeostasis controls cell architecture, growth, and division, we have developed novel labeling approaches. These are compatible with super-resolution fluorescence microscopy to examine peptidoglycan synthesis, hydrolysis, and the localization of the enzymes required for its biosynthesis (penicillin binding proteins (PBPs)). Synthesis of a cephalosporin-based fluorescent probe revealed a pattern of PBPs at the septum during division, supporting a model of dispersed peptidoglycan synthesis. Metabolic and hydroxylamine-based probes respectively enabled the synthesis of glycan strands and associated reducing termini of the peptidoglycan to be mapped. Foci and arcs of reducing termini appear as a result of both synthesis of glycan strands and glucosaminidase activity of the major peptidoglycan hydrolase, SagB. Our studies provide molecular level details of how essential peptidoglycan dynamics are controlled during growth and division.

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