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Coassembly of peptide biomaterials offers a compelling avenue to broaden the spectrum of hierarchically ordered supramolecular nanoscale structures that may be relevant for biomedical and biotechnological applications. In this work coassemblies of amphiphilic and oppositely charged, anionic and cationic, ß-sheet peptides are studied, which may give rise to a diverse range of coassembled forms. Mixtures of the peptides show significantly lower critical coassembly concentration (CCC) values compared to those of the individual pure peptides. Intriguingly, the highest formation of coassembled fibrils is found to require excess of the cationic peptide whereas equimolar mixtures of the peptides exhibited the maximum folding into ß-sheet structures. Mixtures of the peptides coassembled sequentially from solutions at concentrations surpassing each peptide's intrinsic critical assembly concentration (CAC), are also found to require a higher portion of the cationic peptide to stabilize hydrogels. This study illuminates a systematic investigation of oppositely charged ß-sheet peptides over a range of concentrations, in solutions and in hydrogels. The results may be relevant to the fundamental understanding of such intricate charge-driven assembly systems and to the formulation of peptide-based nanostructures with diverse functionalities.
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Neutrophils are the first immune cells to reach inflamed sites and contribute to the pathogenesis of chronic inflammatory skin diseases. Yet, little is known about the pattern of neutrophil infiltration in inflamed skin in vivo and the mechanisms mediating their recruitment. Here, we provide insight into the dynamics of neutrophil infiltration in skin in response to acute or repeated inflammatory stress, highlighting a novel keratinocyte- and keratin 17 (K17)-dependent mechanism that regulates neutrophil recruitment to inflamed skin. We used the phorbol ester TPA and UVB, alone or in combination, to induce sterile inflammation in mouse skin. A single TPA treatment results in a neutrophil influx in the dermis that peaks at 12 h and resolves within 24 h. A subsequent TPA treatment or a UVB challenge, when applied 24 h but not 48 h later, accelerates, amplifies, and prolongs neutrophil infiltration. This transient amplification response (TAR) is mediated by local signals in inflamed skin, can be recapitulated in ex vivo culture, and involves the K17-dependent sustainment of protein kinase Cα (PKCα) activity and release of chemoattractants by stressed keratinocytes. K17 binds RACK1, a scaffold protein essential for PKCα activity. The N-terminal head domain of K17 is crucial for its association with RACK1 and regulation of PKCα activity. Analysis of RNAseq data reveals a signature consistent with TAR and PKCα activation in inflammatory skin diseases. These findings uncover a novel, keratin-dependent mechanism that amplifies neutrophil recruitment in skin under stress, with direct implications for inflammatory skin disorders.
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Queratina-17 , Queratinocitos , Infiltración Neutrófila , Neutrófilos , Proteína Quinasa C-alfa , Piel , Animales , Proteína Quinasa C-alfa/metabolismo , Queratinocitos/metabolismo , Ratones , Piel/metabolismo , Piel/patología , Queratina-17/metabolismo , Queratina-17/genética , Neutrófilos/metabolismo , Ratones Endogámicos C57BL , Humanos , Estrés Fisiológico , Rayos Ultravioleta/efectos adversos , Acetato de Tetradecanoilforbol/farmacología , Receptores de Cinasa C Activada/metabolismo , Receptores de Cinasa C Activada/genética , Femenino , Inflamación/metabolismo , Inflamación/patologíaRESUMEN
Here we present the development of nanoparticles (NPs) formulations specifically designed for targeting the antiapoptotic Bcl-2 proteins on the outer membrane of mitochondria with the drug agent ABT-737. The NPs which are self-assembled by the natural polypeptide poly gamma glutamic acid (ÏPGA) and a designed cationic and amphiphilic peptide (PFK) have been shown to target drugs toward mitochondria. In this study we systematically developed the formulation of such NPs loaded with the ABT-737 and demonstrated the cytotoxic effect of the best identified formulation on MDA-MB-231 cells. Our findings emphasize the critical role of solutions pH and the charged state of the components throughout the formulation process as well as the concentrations of the co-components and their mixing sequence, in achieving the most stable and effective cytotoxic formulation. Our study highlights the potential versatility of designed peptides in combination with biopolymers for improving drug delivery formulations and enhance their targeting abilities.
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A group of keratin intermediate filament genes, the type II KRT6A-C and type I KRT16 and KRT17, are deemed stress responsive as they are induced in keratinocytes of surface epithelia in response to environmental stressors, in skin disorders (e.g., psoriasis) and in carcinomas. Monitoring stress keratins is widely used to identify keratinocytes in an activated state. Here, we analyze single-cell transcriptomic data from healthy and diseased human skin to explore the properties of stress keratins. Relative to keratins occurring in healthy skin, stress-induced keratins are expressed at lower levels and show lesser type I-type II pairwise regulation. Stress keratins do not "replace" the keratins expressed during normal differentiation nor reflect cellular proliferation. Instead, stress keratins are consistently co-regulated with genes with roles in differentiation, inflammation, and/or activation of innate immunity at the single-cell level. These findings provide a roadmap toward explaining the broad diversity and contextual regulation of keratins.
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Neutrophils contribute to the pathogenesis of chronic inflammatory skin diseases. Little is known about the source and identity of the signals mediating their recruitment in inflamed skin. We used the phorbol ester TPA and UVB, alone or in combination, to induce sterile inflammation in mouse skin and assess whether keratinocyte-derived signals impact neutrophil recruitment. A single TPA treatment results in a neutrophil influx in the dermis that peaks at 12h and resolves within 24h. A second TPA treatment or a UVB challenge, when applied at 24h but not 48h later, accelerates, amplifies, and prolongs neutrophil infiltration. This transient amplification response (TAR) is mediated by local signals in inflamed skin, can be recapitulated in ex vivo culture, and involves the K17-dependent sustainment of protein kinase Cα (PKCα) activity and release of neutrophil chemoattractants by stressed keratinocytes. We show that K17 binds RACK1, a scaffold essential for PKCα activity. Finally, analyses of RNAseq data reveal the presence of a transcriptomic signature consistent with TAR and PKCα activation in chronic inflammatory skin diseases. These findings uncover a novel, transient, and keratin-dependent mechanism that amplifies neutrophil recruitment to the skin under stress, with direct implications for inflammatory skin disorders.
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Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease arising from impaired regeneration of the alveolar epithelium after injury. During regeneration, type 2 alveolar epithelial cells (AEC2s) assume a transitional state that upregulates multiple keratins and ultimately differentiate into AEC1s. In IPF, transitional AECs accumulate with ineffectual AEC1 differentiation. However, whether and how transitional cells cause fibrosis, whether keratins regulate transitional cell accumulation and fibrosis, and why transitional AECs and fibrosis resolve in mouse models but accumulate in IPF are unclear. Here, we show that human keratin 8 (KRT8) genetic variants were associated with IPF. Krt8-/- mice were protected from fibrosis and accumulation of the transitional state. Keratin 8 (K8) regulated the expression of macrophage chemokines and macrophage recruitment. Profibrotic macrophages and myofibroblasts promoted the accumulation of transitional AECs, establishing a K8-dependent positive feedback loop driving fibrogenesis. Finally, rare murine transitional AECs were highly senescent and basaloid and may not differentiate into AEC1s, recapitulating the aberrant basaloid state in human IPF. We conclude that transitional AECs induced and were maintained by fibrosis in a K8-dependent manner; in mice, most transitional cells and fibrosis resolved, whereas in human IPF, transitional AECs evolved into an aberrant basaloid state that persisted with progressive fibrosis.
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Fibrosis Pulmonar Idiopática , Queratina-8 , Humanos , Animales , Ratones , Queratina-8/metabolismo , Células Epiteliales Alveolares , Fibrosis Pulmonar Idiopática/metabolismo , Células Epiteliales/metabolismo , Diferenciación CelularRESUMEN
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disorder with currently no cure. Central to the cellular dysfunction associated with this fatal proteinopathy is the accumulation of unfolded/misfolded superoxide dismutase 1 (SOD1) in various subcellular locations. The molecular mechanism driving the formation of SOD1 aggregates is not fully understood but numerous studies suggest that aberrant aggregation escalates with folding instability of mutant apoSOD1. Recent advances on combining organelle-targeting therapies with the anti-aggregation capacity of chemical chaperones have successfully reduce the subcellular load of misfolded/aggregated SOD1 as well as their downstream anomalous cellular processes at low concentrations (micromolar range). Nevertheless, if such local aggregate reduction directly correlates with increased folding stability remains to be explored. To fill this gap, we synthesized and tested here the effect of 9 ER-, mitochondria- and lysosome-targeted chemical chaperones on the folding stability of truncated monomeric SOD1 (SOD1bar) mutants directed to those organelles. We found that compound ER-15 specifically increased the native state stability of ER-SOD1bar-A4V, while scaffold compound FDA-approved 4-phenylbutyric acid (PBA) decreased it. Furthermore, our results suggested that ER15 mechanism of action is distinct from that of PBA, opening new therapeutic perspectives of this novel chemical chaperone on ALS treatment.
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Esclerosis Amiotrófica Lateral , Humanos , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/química , Superóxido Dismutasa-1/metabolismo , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Pliegue de Proteína , Mutación , Chaperonas MolecularesRESUMEN
Developing Future Biologists (DFB) is an inclusive, trainee-run organization that strives to excite and engage the next generation of biologists, regardless of race, gender or socioeconomic status, in the field of developmental biology. DFB offers a week-long course consisting of active lectures, hands-on laboratory sessions, and professional development opportunities through interactions with scientists from a variety of backgrounds and careers. A major goal of DFB is to propel undergraduate students from underserved communities to pursue biomedical research opportunities and advanced degrees in science. To achieve this goal, we provide DFB participants with continuing access to a diverse network of scientists that students can utilize to secure opportunities and foster success throughout multiple stages of their research careers. Here, we describe the flourishing DFB program at the University of Michigan to encourage other institutions to create their own DFB programs.
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Biología Evolutiva , Estudiantes , HumanosRESUMEN
Engaging children in meaningful occupations is a means of improving their participation. The objective of this study is to assess differences in dimensions of meaning of occupations-challenge, value, felt time, and autonomy-between children with and without neurodevelopmental disorders and their associations with the participation of each group. Thirty children with neurodevelopmental disorders (autism spectrum disorder [ASD]/attention deficit hyperactive disorder [ADHD]) and 30 typically developing children (M age = 9.37 ± 1.41 years) reported regarding dimensions of meaning of occupations. Their parents reported regarding children's participation. Children with neurodevelopmental disorders attach different meanings to their everyday activities than their typically developing peers, with a large effect size (ηp2 = .07-.12). For children with neurodevelopmental disorders, the value and autonomy dimensions of meaning were correlated with participation. The findings expand knowledge of occupational meaning and participation among children. To optimize the participation of children, occupational therapists should facilitate autonomy and engage children in activities that they value.
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Trastorno por Déficit de Atención con Hiperactividad , Trastorno del Espectro Autista , Trastornos del Neurodesarrollo , Niño , Humanos , Padres , OcupacionesRESUMEN
Biomass-originated materials are the future's next-tier polymers. This work suggests improving mechanical and barrier properties of nature-sourced polymers using non-covalent supramolecular interactions. Polysaccharide chitosan is modified with amino acids via an esterification pathway using a systematic variation of hydrogen bond and aromatic domains (Degrees of substitution 12-49%). These controlled modifications improve stability due to non-covalent interactions, resulting in biopolymers with tailored thermal (decomposition temperature 232-275 °C), mechanical (Young's modulus 540-2667 MPa), and surface properties (roughness 4-40 nm). Chitosan and natural amino acids that are already manufactured at scale are purposely selected. The facile synthesis, controlled properties, stimuli-responsive potential, and inexhaustible origin of the raw materials provide the presented findings with the potential to become the method for the formation of high-performance biodegradable alternatives to petroleum-based polymers that can be used in packaging, food, agriculture, and medicine.
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Quitosano , Quitosano/química , Biopolímeros/química , Polímeros/química , Temperatura , AminoácidosRESUMEN
A large group of keratin genes (n=54 in the human genome) code for intermediate filament (IF)-forming proteins and show differential regulation in epithelial cells and tissues. Keratin expression can be highly informative about the type of epithelial tissue, differentiation status of constituent cells and biological context (e.g. normal versus diseased settings). The foundational principles underlying the use of keratin expression to gain insight about epithelial cells and tissues primarily originated in pioneering studies conducted in the 1980s. The recent emergence of single cell transcriptomics provides an opportunity to revisit these principles and gain new insight into epithelial biology. Re-analysis of single-cell RNAseq data collected from human and mouse skin has confirmed long-held views regarding the quantitative importance and pairwise regulation of specific keratin genes in keratinocytes of surface epithelia. Furthermore, such analyses confirm and extend the notion that changes in keratin gene expression occur gradually as progenitor keratinocytes commit to and undergo differentiation, and challenge the prevailing assumption that specific keratin combinations reflect a mitotic versus a post-mitotic differentiating state. Our findings provide a blueprint for similar analyses in other tissues, and warrant a more nuanced approach in the use of keratin genes as biomarkers in epithelia.
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Queratinocitos , Queratinas , Ratones , Animales , Humanos , Queratinas/genética , Queratinas/metabolismo , Epitelio/metabolismo , Queratinocitos/metabolismo , Células Epiteliales/metabolismo , Diferenciación Celular/genéticaRESUMEN
Polymer alternatives sourced from nature have attracted increasing attention for applications in medicine, cosmetics, agriculture, food, water purification, and more. Among them, chitosan is the most versatile due to its full biodegradability, exceptional biocompatibility, multipurpose bioactivity, and low toxicity. Although remarkable progress has been made in its synthetic modification by using C3/C6 secondary/primary hydroxy (-OH) and the C2 amino (-NH2 ) active sites, its solubility under physiological conditions remains limited and has hampered larger-scale adoption. This review summarizes different synthetic methods that increase chitosan's hydrophilicity and water solubility by using covalent modifications, namely amino acid addition, quaternary ammonium formation, phosphorylation, and carboxymethylation. We also review several applications for each type of substitution in fields such as cosmetics, medicine, agriculture, and water purification, and provide an outlook and perspective for future modifications and implementations.
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Quitosano , Quitosano/química , Solubilidad , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
Despite the significant progress made over the past decade with combination of molecular profiling data and the development of new clinical strategies, our understanding of metastasis remains elusive. Bone metastasis is a complex process and a major cause of mortality in breast and prostate cancer patients, for which there is no effective treatment to-date. The current review summarizes the routes taken by the metastatic cells and the interactions between them and the bone microenvironment. We emphasize the role of the specified niches and cues that promote cellular adhesion, colonization, prolonged dormancy, and reactivation. Understanding these mechanisms will provide better insights for future studies and treatment strategies for bone metastatic conditions.
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Neoplasias Óseas , Neoplasias de la Próstata , Neoplasias Óseas/genética , Neoplasias Óseas/secundario , Huesos/patología , Humanos , Masculino , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Microambiente TumoralRESUMEN
STUDY DESIGN: A prospective cohort study. OBJECTIVES: To examine the use of a circle-tracing task in quantifying hand functional recovery in cervical spinal cord injury patients. METHODS: Ten cervical spinal cord injury (SCI) patients and 10 healthy age-matched controls performed a circle-tracing task, using a computerized tablet at the beginning of the study and after 4 weeks. Data relative to performance accuracy as well as pen pressure throughout the performances were collected, and clinical assessment for all patients was performed at the beginning and at the end of the study. RESULTS: Significant differences were found in pen pressure profiles in the SCI patients between the initial assessment and after 4 weeks of assessment. SCI patients, when compared with controls, apply less pressure during the execution, though no significant differences were found for the other parameters. Examination of pen pressure profiles of both controls and SCI patients reveals that, in addition to the lower pressure registered, SCI patients present a more oscillating pressure profile which is direction-dependent. No significant correlations were found between clinical assessments and pen pressure, both within the initial assessment as well as after 4 weeks. CONCLUSIONS: This study emphasizes the potential of simple computerized means for quantifying upper limb functions in SCI patients. These results of this study could be helpful for both highlighting specific functional deficits in patients as well tailoring specific interventions.
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Codon usage bias has long been appreciated to influence protein production. Yet, relatively few studies have analyzed the impacts of codon usage on tissue-specific mRNA and protein expression. Here, we use codon-modified reporters to perform an organism-wide screen in Drosophila melanogaster for distinct tissue responses to codon usage bias. These reporters reveal a cliff-like decline of protein expression near the limit of rare codon usage in endogenously expressed Drosophila genes. Near the edge of this limit, however, we find the testis and brain are uniquely capable of expressing rare codon-enriched reporters. We define a new metric of tissue-specific codon usage, the tissue-apparent Codon Adaptation Index (taCAI), to reveal a conserved enrichment for rare codon usage in the endogenously expressed genes of both Drosophila and human testis. We further demonstrate a role for rare codons in an evolutionarily young testis-specific gene, RpL10Aa. Optimizing RpL10Aa codons disrupts female fertility. Our work highlights distinct responses to rarely used codons in select tissues, revealing a critical role for codon bias in tissue biology.
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Drosophila melanogaster , Drosophila , Animales , Codón/genética , Uso de Codones , Drosophila/genética , Drosophila melanogaster/genética , Femenino , Humanos , Masculino , TestículoRESUMEN
Two observational learning approaches have been shown to be successful in improving children's motor performances: one is "technique-focused", another is "goal-focused". In this study, we sought to compare the effectiveness of these two strategies, thus testing for the more efficient method of observational learning to enhance motor skills in primary school children. To this end, two experiments were designed. Experiment 1 involved a precision ball throwing task. Experiment 2 involved a standing long jump task. A total of 792 subjects (aged 6-11) participated in this study and were divided into technique-focus (Experiment 1 n = 200; Experiment 2 n = 66), goal-focus (Experiment 1 n = 195; Experiment 2 n = 68), and control groups (Experiment 1 n = 199; Experiment 2 n = 64). The experiments were divided into pretest, practice, and retention phases. During the practice phase, the technique-focus and goal-focus groups were given different visual instructions on how to perform the task. The results showed that children aged 10-11 belonging to the technique-focus group performed significantly better in the practice phase than both the goal-focus and the control group (p < 0.001), but only for the precision ball throwing task. These findings could be useful for training adaptation in the context of motor learning and skills acquisition.
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Gross and fine motor competence have a close relationship during development and are shown to correlate to some extent. However, the study of the interaction between these domains still requires further insights. In this study, we investigated the developmental changes in overall motor skills as well as the effects of gross motor training programs on fine motor skills in children (aged 6-11, n = 240). Fine motor skills were assessed before and after gross motor intervention using the Box and Block Test. The gross motor intervention was based on the Test of Gross Motor Development-3rd Edition. Results showed that gross and fine motor skills correlate across all years of primary school, both significantly improving with age. Finally, the gross motor intervention appeared to not influence fine motor skills. Our findings show that during primary school age, overall motor development is continuous, but non-linear. From age nine onward, there seems to be a major step-up in overall motor competence, of which teachers/educators should be aware of in order to design motor educational programs accordingly. While gross and fine motor domains might be functionally integrated to enhance children's motor performances, further research is needed to clarify the effect of gross motor practice on fine motor performances.
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Desarrollo Infantil , Trastornos Motores , Niño , Humanos , Destreza Motora , Instituciones AcadémicasRESUMEN
Individual organ development must be temporally coordinated with development of the rest of the organism. As a result, cell division cycles in a developing organ occur on a relatively fixed timescale. Despite this, many developing organs can regenerate cells lost to injury. How organs regenerate within the time constraints of organism development remains unclear. Here, we show that the developing Drosophila hindgut regenerates by accelerating the mitotic cell cycle. This process is achieved by decreasing G1 length and requires the JAK/STAT ligand unpaired-3. Mitotic capacity is then terminated by the steroid hormone ecdysone receptor and the Sox transcription factor Dichaete. These two factors converge on regulation of a hindgut-specific enhancer of fizzy-related, a negative regulator of mitotic cyclins. Our findings reveal how the cell-cycle machinery and cytokine signaling can be adapted to accomplish developmental organ regeneration.
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Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crecimiento & desarrollo , Fase G1 , Tracto Gastrointestinal/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Organogénesis , Regeneración , Animales , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Femenino , Tracto Gastrointestinal/lesiones , Tracto Gastrointestinal/metabolismo , Quinasas Janus/genética , Quinasas Janus/metabolismo , Masculino , Mitosis , Factores de Transcripción SOX/genética , Factores de Transcripción SOX/metabolismo , Factores de Transcripción STAT/genética , Factores de Transcripción STAT/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
How strategies are formulated during a performance is an important aspect of motor control. Knowledge of the strategy employed in a task may help subjects achieve better performances, as it would help to evidence other possible strategies that could be used as well as help perfect a certain strategy. We sought to investigate how much of a performance is conditioned by the initial state and whether behavior throughout the performance is modified within a short timescale. In other words, we focus on the process of execution and not on the outcome. To this scope we used a repeated continuous circle tracing task. Performances were decomposed into different components (i.e., execution variables) whose combination is able to numerically determine movement outcome. By identifying execution variables of speed and duration, we created an execution space and a solution manifold (i.e., combinations of execution variables yielding zero discrepancy from the desired outcome) and divided the subjects according to their initial performance in that space into speed preference, duration preference, and no-preference groups. We demonstrated that specific strategies may be identified in a continuous task, and strategies remain relatively stable throughout the performance. Moreover, as performances remained stable, the initial location in the execution space can be used to determine the subject's strategy. Finally, contrary to other studies, we demonstrated that, in a continuous task, performances were associated with reduced exploration of the execution space.
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Residual motion of upper limbs in individuals who experienced cervical spinal cord injury (CSCI) is vital to achieve functional independence. Several interventions were developed to restore shoulder range of motion (ROM) in CSCI patients. However, shoulder ROM assessment in clinical practice is commonly limited to use of a simple goniometer. Conventional goniometric measurements are operator-dependent and require significant time and effort. Therefore, innovative technology for supporting medical personnel in objectively and reliably measuring the efficacy of treatments for shoulder ROM in CSCI patients would be extremely desirable. This study evaluated the validity of a customized wireless wearable sensors (Inertial Measurement Units-IMUs) system for shoulder ROM assessment in CSCI patients in clinical setting. Eight CSCI patients and eight healthy controls performed four shoulder movements (forward flexion, abduction, and internal and external rotation) with dominant arm. Every movement was evaluated with a goniometer by different testers and with the IMU system at the same time. Validity was evaluated by comparing IMUs and goniometer measurements using Intraclass Correlation Coefficient (ICC) and Limits of Agreement (LOA). inter-tester reliability of IMUs and goniometer measurements was also investigated. Preliminary results provide essential information on the accuracy of the proposed wireless wearable sensors system in acquiring objective measurements of the shoulder movements in CSCI patients.