Fiber Cells Research Articles

The significance of growth shells in development of symmetry, transparency, and refraction of the human lens.

Human visual function depends on the biological lens, a biconvex optical element formed by coordinated, synchronous generation of growth shells produced from ordered cells at the lens equator, the distal edge of the epithelium. Growth shells are comprised of straight (St) and S-shaped (SSh) lens fibers organized in highly symmetric, sinusoidal pattern which optimizes both the refractile, transparent structure and the unique microcirculation that regulates hydration and nutrition over the lifetime of an individual. The fiber cells are characterized by diversity in composition and age. All fiber cells remain interconnected in their growth shells throughout the life of the adult lens. As an optical element, cellular differentiation is constrained by the physical properties of light and its special development accounts for its characteristic symmetry, gradient of refractive index (GRIN), short range transparent order (SRO), and functional longevity. The complex sinusoidal structure is the basis for the lens microcirculation required for the establishment and maintenance of image formation.

Cytological Diagnosis of Malignant Pleural Effusion Caused by Metastatic Squamous Cell Carcinoma: A Series of Four Cases

The majority of malignant pleural effusions are caused by adenocarcinomas, with the most common primary sites being the lung and breast in men and women, respectively. Metastatic squamous cell carcinoma in serous effusions is rare, accounting for less than 3% of all malignant effusions. The most common primary site of origin for metastatic squamous cell carcinoma involving serous effusions is the lung, followed by the head and neck, oesophagus, and cervix. Well-differentiated squamous cell carcinoma in pleural effusion, characterised by keratinised cells with hyperchromatic nuclei, tadpole cells, and fiber cells, is exceedingly rare. Poorly differentiated squamous cell carcinomas often present a diagnostic challenge and can be mistaken for poorly differentiated adenocarcinoma, malignant mesothelioma, or reactive mesothelial hyperplasia. Immunohistochemistry is often required for a definitive diagnosis. Making an accurate diagnosis is crucial for providing optimal treatment to the patient. In this series, four cases (56 years old male,69 years old male, 60 years old female and 81 years old male) of malignant pleural effusion caused by metastatic squamous cell carcinoma arising from the lung, oropharynx, cervix, and oesophagus were examined. While one of the cases involved a well-differentiated squamous cell carcinoma with characteristic cellular morphology that allowed for a straightforward diagnosis, the other three cases were poorly differentiated squamous cell carcinomas that required cell block preparation and immunohistochemistry for confirmation.

Identification of new antioxidant drugs in a human in vitro model of ageing‐associated cataract

Aims/Purpose: Cataracts are a significant cause of global blindness, impacting millions (10.8 million patients), and their prevalence is expected to increase over the coming decades as our populations age. Oxidative stress disrupts ROS (reactive oxygen species) balance in lens fibre cells, leading to lens protein degradation and accumulation, developing age‐related cataracts. The lens has protective mechanisms, including high GSH levels and antioxidant enzymes like catalase, safeguarding lens health. While surgery is currently the only effective treatment, non‐invasive drug‐based approaches show potential by reducing risks and complications. With its potent antioxidant activity, resveratrol may protect lens cells and slow cataract development. However, the limited ability of resveratrol to penetrate lens tissue restricts its direct effects. Therefore, designing new molecules to improve ADME (absorption, distribution, metabolism and excretion) properties is required.Methods: In this study, we used an in vitro model of cataracts by inducing oxidative stress and cell death by adding hydrogen peroxide (H2O2) and luperox to lens epithelial cells to evaluate the protective effects of new molecules against oxidative stress and compared them with resveratrol. Our study assessed the cell viability, intracellular ROS level, mitochondrial function, catalase activity and GSH/GSSH level.Results: These compounds preserved cell viability, reduced ROS levels, maintained mitochondrial function and enhanced catalase activity and GSH levels in lens epithelial cells exposed to H2O2. The novel drugs, CAB‐C1 and CAB‐C2, demonstrated beneficial effects on cellular health.Conclusions: Developing drugs for cataract treatment enables early intervention, particularly for individuals with mild or moderate cataracts who may not require surgery yet. Such advancements might improve patients' quality of life and have implications for ocular science and age‐related eye diseases.

Leveraging transcriptomics-based approaches to enhance genomic prediction: integrating SNPs and gene networks for cotton fibre quality improvement.

Cultivated cotton plants are the world's largest source of natural fibre, where yield and quality are key traits for this renewable and biodegradable commodity. The Gossypium hirsutum cotton genome contains ~80K protein-coding genes, making precision breeding of complex traits a challenge. This study tested approaches to improving the genomic prediction (GP) accuracy of valuable cotton fibre traits to help accelerate precision breeding. With a biology-informed basis, a novel approach was tested for improving GP for key cotton fibre traits with transcriptomics of key time points during fibre development, namely, fibre cells undergoing primary, transition, and secondary wall development. Three test approaches included weighting of SNPs in DE genes overall, in target DE gene lists informed by gene annotation, and in a novel approach of gene co-expression network (GCN) clusters created with partial correlation and information theory (PCIT) as the prior information in GP models. The GCN clusters were nucleated with known genes for fibre biomechanics, i.e., fasciclin-like arabinogalactan proteins, and cluster size effects were evaluated. The most promising improvements in GP accuracy were achieved by using GCN clusters for cotton fibre elongation by 4.6%, and strength by 4.7%, where cluster sizes of two and three neighbours proved most effective. Furthermore, the improvements in GP were due to only a small number of SNPs, in the order of 30 per trait using the GCN cluster approach. Non-trait-specific biological time points, and genes, were found to have neutral effects, or even reduced GP accuracy for certain traits. As the GCN clusters were generated based on known genes for fibre biomechanics, additional candidate genes were identified for fibre elongation and strength. These results demonstrate that GCN clusters make a specific and unique contribution in improving the GP of cotton fibre traits. The findings also indicate that there is room for incorporating biology-based GCNs into GP models of genomic selection pipelines for cotton breeding to help improve precision breeding of target traits. The PCIT-GCN cluster approach may also hold potential application in other crops and trees for enhancing breeding of complex traits.

Integrated single-cell multiomics uncovers foundational regulatory mechanisms of lens development and pathology.

Ocular lens development entails epithelial to fiber cell differentiation, defects in which cause congenital cataracts. We report the first single-cell multiomic atlas of lens development, leveraging snRNA-seq, snATAC-seq and CUT&RUN-seq to discover previously unreported mechanisms of cell fate determination and cataract-linked regulatory networks. A comprehensive profile of cis- and trans-regulatory interactions, including for the cataract-linked transcription factor MAF, is established across a temporal trajectory of fiber cell differentiation. Furthermore, we identify an epigenetic paradigm of cellular differentiation, defined by progressive loss of the H3K27 methylation writer Polycomb repressive complex 2 (PRC2). PRC2 localizes to heterochromatin domains across master-regulator transcription factor gene bodies, suggesting it safeguards epithelial cell fate. Moreover, we demonstrate that FGF hyper-stimulation in vivo leads to MAF network activation and the emergence of novel lens cell states. Collectively, these data depict a comprehensive portrait of lens fiber cell differentiation, while defining regulatory effectors of cell identity and cataract formation.

3D visualization of cellular and molecular distributions in human crystalline lenses at different ages.

The human lens is a highly organized tissue, and it is constructed of delicate inner architectures that ensure its transparency. However, the pattern of cell distribution in the intact lens has rarely been observed or traced in a three-dimensional (3D) perspective. Here, we modified and compared three different kinds of tissue transparency methods to investigate the cellular and molecular changes in the human lens at different ages from a 3D perspective. First, we analyzed the general 3D parameters of cleared human lenses from 6 months to 72 years of age and found that the equator proportion remained constant with age (23.05% ± 0.36). Next, we visualized the cellular distribution patterns in the anterior capsule and equator, as well as the distribution of cortical fiber cells. Interestingly, we observed the accumulation of equatorial epithelium in adolescents and the asymmetrical denucleation of cortical fiber cells in the elderly. Zonula occludens-1 and tropomyosin receptor kinase A were also identified in the pre-equatorial germinative zone, and its presence decreased when comparing lenses of a 17-year-old to those of a 49-year-old. We present a 3D cellular and molecular reconstruction of the human lens, illustrating the observed alterations in human lens epithelial cells across different ages.

A cotton APS REDUCTASE represses root hair elongation via sulfur assimilation and hydrogen peroxide‐mediated cell wall damage

AbstractSulfur is a critical element for plant growth and development, and it is assimilated through a pathway called the sulfur assimilation pathway. APS REDUCTASE (APR) is a key rate‐limiting enzyme in this pathway, and it plays a vital role in regulating sulfur flow and plant development. However, the exact role and mechanism of APR in cotton fiber and root hair development are still not fully understood. This study used in vitro cultured ovules grown on a sulfur‐deficient medium to explore the role of sulfur in fiber development. Genetic approaches such as virus‐induced gene silencing (VIGS) was used to determine the role of target genes. In vitro assays revealed the role of sulfur in fiber development and identified GhAPR2 as a key candidate gene. The GhAPR2 negatively regulates fiber cell initiation and Arabidopsis root hair elongation. Further studies demonstrated that overexpression of GhAPR2 increased the contents of sulfite and GSH to enhance sulfur assimilation in Arabidopsis, leading to abnormal accumulation of ROS in root hair. This down‐regulates the transcription of proline‐rich cell wall protein‐coding genes such as AtEXTs and AtPRPs, reducing the content of hydroxyproline in the cell wall, disrupting the development of the root hair cell wall, and inhibiting root hair elongation. This study elucidated the functional pathway of APR2 in the regulation of root hair development. APR2 first affects sulfur assimilation, which affects the content of reactive oxygen species (ROS), and finally affects the content of hydroxyproline‐rich glycoprotein, which in turn affects the development of root hair. This model also contributes to the understanding of the role of sulfur in fiber development, as well as cell differentiation and development.

Soemmerring's rings developed in‐vivo can present internal transparent areas

Purpose: To test whether any part of Soemmerring's rings developed, in‐vivo, in adults could be transparent and how this transparency relates to morphological factors.Methods: Sixteen Soemmerring's rings were extracted from donor eye globes. After frontal imaging, they were thickly sectioned sagittally in order to analyse the degrees of transparency of the cross‐section both at the periphery and center. All samples were also histologically analysed using alpha smooth muscle actin, Vimentin, wheat germ agglutinin and DAPI in order to correlate transparency to certain morphological factors.Results: When viewed frontally within the dark field, all Soemmerring's ring samples were apparently opaque. However, after sectioning, 20 of the 30 samples were more transparent in the center than at the periphery. Of the morphological factors that we analysed, only lens fibre organization at the bow region and an increased area of mature lens fibre cells had a significant relation to the degree of transparency at the center of cross‐sections.Conclusions: Soemmerring's rings can maintain the ability to produce organized and transparent areas of lens cells.

Self‐Micropatterned Wood Hydrophone for Underwater Detection

AbstractA hydrophone is a core component of sonar and plays a significant role in underwater detection. High sensitivity and wide‐frequency responsiveness are crucial parameters for underwater mechanosensors. This study introduces an innovative wood‐based hydrophone for precise detection of water wave spectra and a wide range of underwater sounds. The wood hydrophone consists of a conductive wood electrode with deposited polypyrrole (PPy) microbranches (polypyrrole wood (PW)) and a cellulosic micropatterned anti‐swelling hydrogel (MPASH) serving as the dielectric layer. As pressure increases within the range of 6.4 Pa to 1.2 kPa, the densely distributed PPy microbranches within the wood fiber cell lumina contact with more tips of the self‐wrinkled micropatterns of MPASH. This interaction results in a four‐order‐of‐magnitude increase in capacitance, leading to an unprecedented sensitivity of 1153 kPa−1 toward microstresses. Due to the presence of multisized configurations in both PW and MPASH, the sensitivity of the wood hydrophone decreases gradually (268 kPa−1 up to 37 kPa). The receiving sensitivity of the wood hydrophone for acoustic waves is greater than ‐174 dB within the frequency range of 250–2300 Hz. This work presents a promising avenue for the development of underwater detection devices utilizing graded wood channels and micropatterned cellulosic hydrogels.

Human Cx50 Isoleucine177 prevents heterotypic docking and formation of functional gap junction channels with Cx43.

The human lens is an avascular organ, and its transparency is dependent on gap junction (GJ)-mediated microcirculation. Lens GJs are composed of three connexins with Cx46 and Cx50 being expressed in lens fiber cells and Cx43 and Cx50 in the epithelial cells. Impairment of GJ communication by either Cx46 or Cx50 mutations has been shown to be one of the main molecular mechanisms of congenital cataracts in mutant carrier families. The docking compatibility and formation of functional heterotypic GJs for human lens connexins have not been studied. Previous study on rodent lens connexins revealed that Cx46 can form functional heterotypic GJs with Cx50 and Cx43, but Cx50 cannot form heterotypic GJ with Cx43 due to its second extracellular (EL2) domain. To study human lens connexin docking and formation of functional heterotypic GJs, we developed a genetically engineered HEK293 cell line with endogenously expressed Cx43 and Cx45 ablated. The human lens connexins showed docking compatibility identical to those found in the rodent connexins. To reveal the structural mechanisms of the docking incompatibility between Cx50 and Cx43, we designed eight variants based on the differences between the EL2 of Cx50 and Cx46. We found that Cx50I177L is sufficient to establish heterotypic docking with Cx43 with some interesting gating properties. Our structure models indicate this residue is important for interdomain interactions within a single connexin, Cx50 I177L showed an increased interdomain interaction which might alter the docking interface structure to be compatible with Cx43.NEW & NOTEWORTHY The human lens is an avascular organ, and its transparency is partially dependent on gap junction (GJ) network composed of Cx46, Cx50, and Cx43. We found that human Cx46 can dock and form functional heterotypic GJs with Cx50 and Cx43, but Cx50 is unable to form functional heterotypic GJs with Cx43. Through mutagenesis and patch-clamp study of several designed variants, we found that Cx50 I177L was sufficient to form functional heterotypic GJs with Cx43.

RHOAL57V drives the development of diffuse gastric cancer through IGF1R-PAK1-YAP1 signaling.

Cancer-associated mutations in the guanosine triphosphatase (GTPase) RHOA are found at different locations from the mutational hotspots in the structurally and biochemically related RAS. Tyr42-to-Cys (Y42C) and Leu57-to-Val (L57V) substitutions are the two most prevalent RHOA mutations in diffuse gastric cancer (DGC). RHOAY42C exhibits a gain-of-function phenotype and is an oncogenic driver in DGC. Here, we determined how RHOAL57V promotes DGC growth. In mouse gastric organoids with deletion of Cdh1, which encodes the cell adhesion protein E-cadherin, the expression of RHOAL57V, but not of wild-type RHOA, induced an abnormal morphology similar to that of patient-derived DGC organoids. RHOAL57V also exhibited a gain-of-function phenotype and promoted F-actin stress fiber formation and cell migration. RHOAL57V retained interaction with effectors but exhibited impaired RHOA-intrinsic and GAP-catalyzed GTP hydrolysis, which favored formation of the active GTP-bound state. Introduction of missense mutations at KRAS residues analogous to Tyr42 and Leu57 in RHOA did not activate KRAS oncogenic potential, indicating distinct functional effects in otherwise highly related GTPases. Both RHOA mutants stimulated the transcriptional co-activator YAP1 through actin dynamics to promote DGC progression; however, RHOAL57V additionally did so by activating the kinases IGF1R and PAK1, distinct from the FAK-mediated mechanism induced by RHOAY42C. Our results reveal that RHOAL57V and RHOAY42C drive the development of DGC through distinct biochemical and signaling mechanisms.

Chemical properties, crystallinity, and fiber biometry of Jabon (Anthocephalus cadamba) wood for pulp raw material: the effect of age and position

Abstract Jabon (Anthocephalus cadamba) is a promising plant species with straight, visually pleasing trunks that can be harvested at a young age as a resource for pulp and paper production due to the rapid growth rate possessed. Therefore, this study aims to investigate the chemical composition and fiber biometry of 3, 6, and 9-year-old Jabon wood, determining their suitability as a pulp and paper raw material. Samples were collected from both stem and branch sections and analyzed according to the Tappi standard. Fiber cell maceration was conducted to enable the precise measurement of fiber dimensions and derivatives. The results showed high cellulose, holocellulose, and lignin content in Jabon wood, with low to moderate levels of extractives and ash. Additionally, the crystallinity index (CrI) increased with age, particularly from 3 to 9 years old. The branch of the plant, with Grade II fiber derivative quality, had lower CrI compared to the stem, while the inner stem showed a lesser value than the outer part. In conclusion, 3-year-old Jabon wood is a potential raw material for pulp and paper production.

Modeling Cataract Surgery in Mice.

Cataract surgery (CS) is an effective treatment for cataracts, a major cause of visual disability worldwide. However, CS leads to ocular inflammation, and in the long term, it can result in posterior capsular opacification (PCO) and/or lens dislocation driven by the post-surgical overgrowth of lens epithelial cells (LECs) and their conversion to myofibroblasts and/or aberrant fiber cells. However, the molecular mechanisms by which CS results in inflammation and PCO are still obscure because most in vitro models do not recapitulate the wound healing response of LECs seen in vivo, while traditional animal models of cataract surgery, such as rabbits, do not allow the genetic manipulation of gene expression to test mechanisms. Recently, our laboratory and others have successfully used genetically modified mice to study the molecular mechanisms that drive the induction of proinflammatory signaling and LEC epithelial to mesenchymal transition, leading to new insight into PCO pathogenesis. Here, we report the established protocol for modeling cataract surgery in mice, which allows for robust transcriptional profiling of the response of LECs to lens fiber cell removal via RNAseq, the evaluation of protein expression by semi-quantitative immunofluorescence, and the use of modern mouse genetics tools to test the function of genes that are hypothesized to participate in the pathogenesis of acute sequelae like inflammation as well as the later conversion of LECs to myofibroblasts and/or aberrant lens fiber cells.

Self-organizing behaviors of cardiovascular cells on synthetic nanofiber scaffolds.

In tissues and organs, the extracellular matrix (ECM) helps maintain inter- and intracellular architectures that sustain the structure-function relationships defining physiological homeostasis. Combining fiber scaffolds and cells to form engineered tissues is a means of replicating these relationships. Engineered tissues' fiber scaffolds are designed to mimic the topology and chemical composition of the ECM network. Here, we asked how cells found in the heart compare in their propensity to align their cytoskeleton and self-organize in response to topological cues in fibrous scaffolds. We studied cardiomyocytes, valvular interstitial cells, and vascular endothelial cells as they adapted their inter- and intracellular architectures to the extracellular space. We used focused rotary jet spinning to manufacture aligned fibrous scaffolds to mimic the length scale and three-dimensional (3D) nature of the native ECM in the muscular, valvular, and vascular tissues of the heart. The representative cardiovascular cell types were seeded onto fiber scaffolds and infiltrated the fibrous network. We measured different cell types' propensity for cytoskeletal alignment in response to fiber scaffolds with differing levels of anisotropy. The results indicated that valvular interstitial cells on moderately anisotropic substrates have a higher propensity for cytoskeletal alignment than cardiomyocytes and vascular endothelial cells. However, all cell types displayed similar levels of alignment on more extreme (isotropic and highly anisotropic) fiber scaffold organizations. These data suggest that in the hierarchy of signals that dictate the spatiotemporal organization of a tissue, geometric cues within the ECM and cellular networks may homogenize behaviors across cell populations and demographics.

Evaluation of Optical Characteristic of Animal Fat using Au Nanoparticle in Bamboo-derived Nanocellulose Paper Substrate: A Comparative Study

Detection of animal fat content is necessary to prevent inappropriate product composition labelling measures such as substituting beef with pork or adding lard to other fat-processed products. In this paper, a detection method of animal fat utilizing paper-based biosensors using nano cellulose paper substrate is proposed. The nanocellulose paper substrate was fabricated using bamboo fibre and parenchyma cells. The nanocellulose paper substrate was further decorated with Au nanoparticles to improve the detection’s sensitivity. It demonstrated the measurement of optical properties using UV-vis spectroscopy for several animal fats. It also presented a colorimetric detection using a light source, photodetector, and imaging analysis. It was shown the difference in the color space intensity value before and after the addition of lard samples on AuNP-modified nanocellulose paper. It was reported that the difference in grayscale intensity value of AuNP-modified nanocellulose paper with a reducing agent volume of 3 mL and 4 mL were 37.369 and 55.686, respectively. This demonstrated that the larger the volume of reducing agent added during synthesis, the smaller the size of the nanoparticles and increasing the sensitivity of the sensor. The proposed paper-based biosensor offered a simple fabrication, biodegradable, and can be implemented in a colorimetric imaging system.

Solute imbibition in paper strip: Pore-scale insights into the concentration-dependent permeability

Capillary wicking in a thicker gel blot microfluidics paper has been investigated through a combination of an analytical framework, experiments, and numerical simulations. The primary objectives of this work are to investigate the concentration-dependent wicking process inside thicker microfluidic paper and to estimate the concentration-dependent permeability using both theoretical models and experimental data. An additional goal is to estimate the parameters for saturation-dependent flow modeling in thicker microfluidic paper. To comprehend the wicking phenomenon on thicker gel blot paper, a series of experiments employing aqueous food dye solutions at varying concentrations has been conducted. In order to calculate the temporal wicking length analytically, the Brinkman-extended Darcy equation is implemented. By modifying the permeability expression for a simple rectangular unidirectional fiber cell and pure liquid, the expression of effective permeability for the analytical framework has also been introduced. The concentrations of the food dye solutions appear to have a substantial influence on the wicking phenomenon. Effective permeability and wicking length have been found to follow a decreasing pattern at lower concentrations while both increase at higher values. Intriguingly, employing a microfluidics paper with a relatively greater thickness facilitates the visualization of the fluid front. This phenomenon is identified by the formation of an acute angle at intermediate time instants, while the fluid front angle assumes an angle nearly ∼90° during smaller and higher time instants. In order to evaluate the saturation-dependent capillary pressure and permeability, the empirical correlation of concentration-dependent Brooks and Corey parameters is additionally determined experimentally. These parameters are subsequently employed in numerical simulations to illustrate the saturation-dependent flow field using Richards’ equation. Furthermore, numerical simulations based on these estimated model parameters have been conducted, and it turns out that the saturation field has an excellent agreement with the experimental results. The results of the current study can be used to design low-cost paper-based diagnostic devices for usage in healthcare and environmental applications.

Predicting the effect of microstructural variations in porous sound absorbers on their sound absorption performance using the perturbation method

Noise reduction is one of the most important issues in various industries. Quantifying the variation in acoustic properties is an essential task to improve the quality of products. Porous sound-absorbing materials are commonly applied to reduce noise. Variations in the microstructure of porous materials have a significant impact on variations of sound absorption coefficient. Experimental methods have been used to predict manufacturing variability of sound-absorbing porous materials. However, they take a lot of time and cost. In this study, a perturbation method is applied to predict variations of sound absorption coefficient of sound-absorbing porous materials combined with the homogenization method based on an asymptotic expansion. Properties of microstructure of a sound-absorbing porous material, such as fiber diameter and cell size, are assumed to follow normal distribution and identify the expectation and variance from the observation of microscopic images obtained by scanning electron microscope. Calculated variability of sound absorption coefficient is compared with measured variability and they agree well in the frequency range of interest.

Variations in the Vascular Bundle and Fiber Structure during the Stem Development of Rattan (Calamus caesius Blume)

Calamus caesius is one of the most well-known commercial climbing palm species across the world. A comprehensive understanding of the growth-dependent variation in microstructure and polymer distribution can provide fundamental information to guide its end-use applications. In this study, we investigated the age-wise characteristics of rattan stems and the ultrastructure of fibers using electron microscopy, light microscopy, and FTIR. The results showed that the frequency of vascular bundles with a diameter of 0.55∼0.62 mm in C. caesius was 3.49∼3.97 pieces/mm2. The diameter and length of the metaxylem vessel were 0.32∼0.34 mm and 2.86∼3.00 mm, respectively. Cellulose, lignin, xylan, and HCA are mainly concentrated in the fiber sheath of vascular bundles. The distribution of major polymers in positions other than the top was relatively stable. The tissue proportion of parenchyma, xylem, and phloem did not differ significantly at different positions. The proportion of fibers from 22.27%∼25.33% showed significant differences. The fiber length was 1.43∼1.76 mm, and the diameter was 10.78∼12.63 μm. During the growth process of the rattan stem, the secondary wall of fiber cells continued to accumulate inward towards the cell cavity from 2 to 6 layers. The unique fiber properties and stable vascular bundle composition of C. caesius may have potential in fields such as composite materials or renewable energy.

GhMYB30-GhMUR3 affects fiber elongation and secondary wall thickening in cotton.

Xyloglucan, an important hemicellulose, plays a crucial role in maintaining cell wall structure and cell elongation. However, the effects of xyloglucan on cotton fiber development are not well understood. GhMUR3 encodes a xyloglucan galactosyltransferase that is essential for xyloglucan synthesis and is highly expressed during fiber elongation. In this study, we report that GhMUR3 participates in cotton fiber development under the regulation of GhMYB30. Overexpression GhMUR3 affects the fiber elongation and cell wall thickening. Transcriptome showed that the expression of genes involved in secondary cell wall synthesis was prematurely activated in OE-MUR3 lines. In addition, GhMYB30 was identified as a key regulator of GhMUR3 by Y1H, Dual-Luc, and electrophoretic mobility shift assay (EMSA) assays. GhMYB30 directly bound the GhMUR3 promoter and activated GhMUR3 expression. Furthermore, DAP-seq of GhMYB30 was performed to identify its target genes in the whole genome. The results showed that many target genes were associated with fiber development, including cell wall synthesis-related genes, BR-related genes, reactive oxygen species pathway genes, and VLCFA synthesis genes. It was demonstrated that GhMYB30 may regulate fiber development through multiple pathways. Additionally, GhMYB46 was confirmed to be a target gene of GhMYB30 by EMSA, and GhMYB46 was significantly increased in GhMYB30-silenced lines, indicating that GhMYB30 inhibited GhMYB46 expression. Overall, these results revealed that GhMUR3 under the regulation of GhMYB30 and plays an essential role in cotton fiber elongation and secondary wall thickening. Additionally, GhMYB30 plays an important role in the regulation of fiber development and regulates fiber secondary wall synthesis by inhibiting the expression of GhMYB46.

Acetylenic tricyclic bis-(cyano enone) interacts with Cys 374 of actin, a residue necessary for stress fiber formation and cell migration

The migratory and invasive potential of tumour cells relies on the actin cytoskeleton. We previously demonstrated that the tricyclic compound, TBE-31, inhibits actin polymerization and here we further examine the precise interaction between TBE-31 and actin. We demonstrate that iodoacetamide, a cysteine (Cys) alkylating agent, interferes with the ability of TBE-31 to interact with actin. In addition, in silico analysis identified Cys 217, Cys 272, Cys 285 and Cys 374 as potential binding sites for TBE-31. Using mass spectrometry analysis, we determined that TBE-31 associates with actin with a stoichiometric ratio of 1:1. We mutated the identified cysteines of actin to alanine and performed a pull-down analysis with a biotin labeled TBE-31 and demonstrated that by mutating Cys 374 to alanine the association between TBE-31 and actin was significantly reduced, suggesting that TBE-31 binds to Cys 374. A characterization of the NIH3T3 cells overexpressing eGFP-actin-C374A showed reduced stress fiber formation, suggesting Cys 374 is necessary for efficient incorporation into filamentous actin. Furthermore, migration of eGFP-Actin-WT expressing cells were observed to be inhibited by TBE-31, however fewer eGFP-Actin-C374A expressing cells were observed to migrate compared to the cells expressing eGFP-Actin-WT in the presence or absence of TBE-31. Taken together, our results suggest that TBE-31 binds to Cys 374 of actin to inhibit actin stress fiber formation and may potentially be a mechanism through which TBE-31 inhibits cell migration.