The lung is the primary respiratory organ in human, in which the proximal airway and the distal alveoli are responsible for air conduction and gas exchange, respectively. However, the regulation of ...proximal-distal patterning at the embryonic stage of human lung development is largely unknown. Here we investigated the early lung development of human embryos at weeks 4-8 post fertilization (Carnegie stages 12-21) using single-cell RNA sequencing, and obtained a transcriptomic atlas of 169,686 cells. We observed discernible gene expression patterns of proximal and distal epithelia at week 4, upon the initiation of lung organogenesis. Moreover, we identified novel transcriptional regulators of the patterning of proximal (e.g., THRB and EGR3) and distal (e.g., ETV1 and SOX6) epithelia. Further dissection revealed various stromal cell populations, including an early-embryonic BDNF
population, providing a proximal-distal patterning niche with spatial specificity. In addition, we elucidated the cell fate bifurcation and maturation of airway and vascular smooth muscle progenitor cells at the early stage of lung development. Together, our study expands the scope of human lung developmental biology at early embryonic stages. The discovery of intrinsic transcriptional regulators and novel niche providers deepens the understanding of epithelial proximal-distal patterning in human lung development, opening up new avenues for regenerative medicine.
Chondrocyte mechanotransduction is not well understood, but recently, it has been proposed that mechanically activated ion channels such as transient receptor potential vanilloid 4 (TRPV4), Piezo1, ...and Piezo2 are of functional importance in chondrocyte mechanotransduction. The aim of this study was to distinguish the potential contributions of TRPV4, Piezo1, and Piezo2 in transducing different intensities of repetitive mechanical stimulus in chondrocytes. To study this, TRPV4-, Piezo1-, or Piezo2-specific siRNAs were transfected into cultured primary chondrocytes to knock down (KD) TRPV4, Piezo1, or Piezo2 expression, designated TRPV4-KD, Piezo1-KD, or Piezo2-KD cells. Then we used Flexcell® Tension System to apply cyclic tensile strains (CTS) of 3% to 18% at 0.5 Hz for 8 h to the knockdown and control siRNA-treated cells. Finally, using a Ca
2+
imaging system, stretch-evoked intracellular Ca
2+
(Ca
2+
i
) influx in chondrocytes was examined to investigate the roles of TRPV4, Piezo1, and Piezo2 in Ca
2+
signaling in response to different intensities of repetitive mechanical stretch stimulation. The characteristics of Ca
2+
i
in chondrocytes evoked by stretch stimulation were stretch intensity dependent when comparing unstretched cells. In addition, stretch-evoked Ca
2+
i
changes were significantly suppressed in TRPV4-KD, Piezo1-KD, or Piezo2-KD cells compared with control siRNA-treated cells, indicating that any channel essential for Ca
2+
signaling induced by stretch stimulation in chondrocytes. Of note, they played different roles in calcium oscillation induced by different intensities of stretch stimulation. More specifically, TRPV4-mediated Ca
2+
signaling played a central role in the response of chondrocytes to physiologic levels of strain (3% and 8% of strain), while Piezo2-mediated Ca
2+
signaling played a central role in the response of chondrocytes to injurious levels of strain (18% of strain). These results provide a basis for further examination of mechanotransduction in cartilage and raise a possibility of therapeutically targeting Piezo2-mediated mechanotransduction for the treatment of cartilage disease induced by repetitive mechanical forces.
Impact statement
Chondrocytes in cartilage are constantly subjected to load-induced stimuli and regulate their metabolic activities in order to maintain cartilage homeostasis. Therefore, mechanotransduction is important in chondrocytes and is vital for their role in cartilage function. Our results indicate that chondrocytes might sense and distinguish the different intensities of repetitive mechanical stimulus by using different mechanosensitive ion channels. Specifically, TRPV4 is mainly responsible for sensing physiologic levels of repetitive CTS stimulus, while Piezo2 mainly contributes to chondrocyte sensing noxious levels of repetitive CTS loading. These results provide a basis for further examination of mechanotransduction in cartilage and raise the possibility of therapeutically targeting Piezo2-mediated mechanotransduction for the treatment of OA which is induced by injurious and repetitive mechanical stimulation.
A series of the windmill‐like fluorenoid nanogrid were synthesized by BF3·Et2O‐mediated Friedel–Crafts reaction. Two typical routes to synthesize square windmill‐like nanogrid (WG4) were developed. A ...one step synthesis using an I‐shaped building block with a yield of 18 % and by‐products of triangular nanogrid (WG3) and pentagon nanogrid (WG5) as well as multi‐step synthesis using an l‐shaped building block with a higher total yield of 53 %. Meanwhile, two isomers were separated for the triangle nanogrids (WG3), one of which has been confirmed by single‐crystal X‐ray diffraction.
Various sizes of windmill‐like nanogrids were synthesized by two bottom‐up strategies, i.e., I‐ and l‐shape building block synthetic methods. A BF3·Et2O‐mediated Friedel–Crafts reaction of TPFOH resulted in the windmill‐like nanogrids (WG3, WG4 and WG5) from the I‐shape building block synthetic method. For the synthetic method of l‐shaped building block, the cyclization process possessed higher selectivity, resulting in an excellent yield of WG4.
Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent data sets from ...whole-genome shotgun sequencing were merged and assembled together with newly obtained fosmid- and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5-fold sequence coverage of an estimated 432
Mb genome was assembled into scaffolds with an N50 size of ∼3.7
Mb; the largest scaffold was 14.5 million base pairs. With help of a high-density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes.
Oncolytic virus (OV) therapy as a cancer therapy that improves immune status makes it a favorable candidate for optimizing immunotherapy strategies. Existing studies have focused on characterizing ...the disturbance of the tumor microenvironment (TME) by OV therapy. However, the changes in systemic immunity induced by OV were largely ignored, which would prevent the further understanding and optimization of oncolytic viruses.
The HSV-2-based oncolytic virus OH2 was used to treat tumor-bearing mouse models. The peripheral blood samples were then collected for single-cell RNA sequencing (scRNA-seq). The scRNA-seq data were analyzed using Cell Ranger, Seurat, and other bioinformatics tools. Key findings were further validated by ELISA, immunohistochemistry, flow cytometry, in vivo experiments, and clinical samples.
Our data showed that OH2 therapy effectively activated systemic immunity and induced a sustained anti-tumor immune response. One major impact of OH2 on systemic immunity was to boost Ccl5 production, which correlated with clinical response. Besides, the cytotoxic ability of peripheral cytotoxic Cd8+ T cells and mature NK cells was elevated by OH2. Further analysis revealed that the interaction of monocytes with T cells and NK cells was critical for systemic immune remodeling and activation. We also found that systemic immune responses induced by OH2 could effectively reshape the microenvironment of distant tumor lesions and inhibit their progression.
This study is the first to comprehensively characterize the effects of OV therapy on systemic immunity, which not only sheds new light on the anti-tumor mechanisms of OH2, but also contributes to the establishment of companion diagnostics for OH2 treatment and the improvement of oncolytic therapy strategies.
Although the performance of organic semiconductor devices has reached the standard of commercial products after several decades of development, the stability of organic semiconducting materials ...remains a key factor that severely impedes the long-term operation of organic electronics in the practical applications. In this study, a conjugated nanopolymer based on a nanogrid was synthesized and systematically examined, and it was compared with two other types of polyfluorenes in terms of the stability, including thermal, spectral, morphological, and electroluminescent stability. These results reveal that the grid structure in PG-C8 nanopolymer not only enables higher thermal and spectral stability but also provides better morphology stability and electroluminescent stability than traditional linear polyfluorene PFO and polyfluorene PH with nongrid steric hindrance. Therefore, research into optimized nanogrid-based nanopolymers can be an effective strategy for obtaining comprehensively ultrastable materials and devices for plastic electronics.
The complete mitochondrial genome of Chinese Bombyx mandarina (ChBm) was determined. The circular genome is 15682 bp long, and contains a typical gene complement, order, and arrangement identical to ...that of Bombyx mori (B. mori) and Japanese Bombyx mandarina (JaBm) except for two additional tRNA-like structures: tRNA( Ser(TGA))-like and tRN( AIle(TAT))-like. All protein-coding sequences are initiated with a typical ATN codon except for the COI gene, which has a 4-bp TTAG putative initiator codon. Eleven of 13 protein-coding genes (PCGs) have a complete termination codon (all TAA), but the remaining two genes terminate with incomplete codons. All tRNAs have the typical clover-leaf structures of mitochondrial tRNAs, with the exception of tRNA( Ser(TGA))-like, with a four stem-and-loop structure. The length of the A+T-rich region of ChBm is 484 bp, shorter than those of JaBm (747 bp) and B. mori (494-499 bp). Phylogenetic analysis among B. mori, ChBm, JaBm, and Antheraea pernyi (Anpe) showed that B. mori is more closely related to ChBm than JaBm. The earliest divergence time estimate for B. mori-ChBm and B. mori-JaBm is about 1.08+/-0.18-1.41+/-0.24 and 1.53+/-0.20-2.01+/-0.26 Mya, respectively. ChBm and JaBm diverged around 1.11+/-0.16-1.45+/-0.21 Mya.
With the development of biomaterials, more attention is paid to the adhesion characteristics between cells and materials. It is necessary to study the adhesive force with a suitable method. Silk ...fibroin (SF) is widely investigated in biomedical application due to its novel biocompatibility and mechanical properties. In this article, the micropipette aspiration method and measurement pattern of uniform cells in round shape (UCR) was used to study the initial adhesive force of three types of cells on pure silk fibroin films (SFFs). We also compared the adhesive forces of modified SFFs with that of pure SFFs. The results of adhesive force in the initial adhesive stage were in concordance with the results of MTT assay and microscope observation, which were confirmed by the above three cell lines and four kinds of SFFs. The results indicated UCR was an efficient and quantitative measurement pattern in initial adhesion stage. This article also provides a useful method in identifying initial cell-materials interactions.
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