CD201+ fascia progenitors choreograph injury repair

Optimal tissue recovery and organismal survival are achieved by spatiotemporal tuning of tissue inflammation, contraction and scar formation1. Here we identify a multipotent fibroblast progenitor marked by CD201 expression in the fascia, the deepest connective tissue layer of the skin. Using skin injury models in mice, single-cell transcriptomics and genetic lineage tracing, ablation and gene deletion models, we demonstrate that CD201+ progenitors control the pace of wound healing by generating multiple specialized cell types, from proinflammatory fibroblasts to myofibroblasts, in a spatiotemporally tuned sequence. We identified retinoic acid and hypoxia signalling as the entry checkpoints into proinflammatory and myofibroblast states. Modulating CD201+ progenitor differentiation impaired the spatiotemporal appearances of fibroblasts and chronically delayed wound healing. The discovery of proinflammatory and myofibroblast progenitors and their differentiation pathways provide a new roadmap to understand and clinically treat impaired wound healing.

Cdc42-Borg4-Septin7 axis regulates HSC polarity and function

Aging of hematopoietic stem cells (HSCs) is caused by the elevated activity of the small RhoGTPase Cdc42 and an apolar distribution of proteins. Mechanisms by which Cdc42 activity controls polarity of HSCs are not known. Binder of RhoGTPases proteins (Borgs) are known effector proteins of Cdc42 that are able to regulate the cytoskeletal Septin network. Here, we show that Cdc42 interacts with Borg4, which in turn interacts with Septin7 to regulate the polar distribution of Cdc42, Borg4, and Septin7 within HSCs. Genetic deletion of either Borg4 or Septin7 results in a reduced frequency of HSCs polar for Cdc42 or Borg4 or Septin7, a reduced engraftment potential and decreased lymphoid‐primed multipotent progenitor (LMPP) frequency in the bone marrow. Taken together, our data identify a Cdc42‐Borg4‐Septin7 axis essential for the maintenance of polarity within HSCs and for HSC function and provide a rationale for further investigating the role of Borgs and Septins in the regulation of compartmentalization within stem cells.

Megakaryoblastic leukemia: a study on novel role of clinically significant long non-coding RNA signatures in megakaryocyte development during treatment with phorbol ester

Acute megakaryocytic leukemia (AMKL) is one of the rarest sub-types of acute myeloid leukemia (AML). AMKL is characterized by high proliferation of megakaryoblasts and myelofibrosis of bone marrow, this disease is also associated with poor prognosis. Previous analyses have reported that the human megakaryoblastic cells can be differentiated into cells with megakaryocyte (MK)-like characteristics by phorbol 12-myristate 13-acetate (PMA). However, little is known about the mechanism responsible for regulating this differentiation process. We performed long non-coding RNA (lncRNA) profiling to investigate the differently expressed lncRNAs in megakaryocyte blast cells treated with and without PMA and examined those that may be responsible for the PMA-induced differentiation of megakaryoblasts into MKs. We found 30 out of 90 lncRNA signatures to be differentially expressed after PMA treatment of megakaryoblast cells, including the highly expressed JPX lncRNA. Further, in silico lncRNA-miRNA and miRNA-mRNA interaction analysis revealed that the JPX is likely involved in unblocking the expression of TGF-β receptor (TGF-βR) by sponging oncogenic miRNAs (miR-9-5p, miR-17-5p, and miR-106-5p) during MK differentiation. Further, we report the activation of TGF-βR-induced non-canonical ERK1/2 and PI3K/AKT pathways during PMA-induced MK differentiation and ploidy development. The present study demonstrates that TGF-βR-induced non-canonical ERK1/2 and PI3K/AKT pathways are associated with PMA-induced MK differentiation and ploidy development; in this molecular mechanism, JPX lncRNA could act as a decoy for miR-9-5p, miR-17-5p, and miR-106-5p, titrating them away from TGF-βR mRNAs. Importantly, this study reveals the activation of ERK1/2 and PI3K/AKT pathway in PMA-induced Dami cell differentiation into MK. The identified differentially expressed lncRNA signatures may facilitate further study of the detailed molecular mechanisms associated with MK development. Thus, our data provide numerous targets with therapeutic potential for the modulation of the differentiation of megakaryoblastic cells in AMKL.

Epigenetic Mechanisms: Role in Hematopoietic Stem Cell Lineage Commitment and Differentiation

Major breakthroughs in the last several decades have contributed to our knowledge of the genetic regulation in development. Although epigenetics is not a new concept, unfortunately, the role of epigenetics has not come to fruition in the past. But the field of epigenetics has exploded within the past decade. Now, growing evidences show a complex network of epigenetic regulation in development. The epigenetic makeup of a cell, tissue or individual is much more complex than their genetic complement. Epigenetic modifications are more important for normal development by maintaining the gene expression pattern in tissue- and context-specific manner. Deregulation of epigenetic mechanism can lead to altered gene expression and its function, which result in altered tissue specific function of cells and malignant transformation. Epigenetic modifications directly shape Hematopoietic Stem Cell (HSC) developmental cascades, including their maintenance of self-renewal and multilineage potential, lineage commitment, and aging. Hence, there is a growing admiration for epigenetic players and their regulatory function in haematopoiesis. Epigenetic mechanisms underlying these modifications in mammalian genome are still not completely understood. This review mainly explains 3 key epigenetics mechanisms including DNA methylation, histone modifications and non-coding RNAs inference in hematopoietic lineage commitment and differentiation.

Role of Aromatic Moiety in the Probe Property toward Picric Acid: Synthesis, Crystal Structure, Spectroscopy, Microscopy, and Computational Modeling of a Knoevenagel Condensation Product of d-Glucose

Molecular probes for picric acid (PA) in both solution and solid states are important owing to their wide usage in industry. This paper deals with the design and development of a glucosyl conjugate of pyrene (L 1 ) along with control molecular systems, possessing anthracenyl (L 2 ), naphtyl (L 3 ), and phenyl (L 4 ) moieties, via Knoevenagel condensation of 2,4-pentanedione with d-glucose. The selectivity of L 1 toward PA has been demonstrated on the basis of fluorescence and absorption spectroscopy, and the species of recognition by electrospray ionization mass spectrometry. The role of the aromatic group in the selective receptor property has been addressed among L 1 , L 2 , L 3 , and L 4 . The structural features of the {L 1 + PA} complex were established by density functional theory computations. L 1 was demonstrated to detect PA in solid state selectively over other nitroaromatic compounds (NACs). To study the utility of L 1 in film, cellulose paper strips coated with L 1 were used and demonstrated the selective detection of PA. The observed microstructural features of L 1 and its complex {L 1 + PA} differ distinctly in both atomic force microscopy and scanning electron microscopy, all in the support of the complex formation. Thus, L 1 was demonstrated as a sensitive, selective, and inexpensive probe for PA over several NACs by visual, spectral, and microscopy methods.

Wheat germ agglutinin modified magnetic iron oxide nanocomplex as a cell membrane specific receptor target material for killing breast cancer cells

Lectins are known for their specificity for carbohydrate binding. However, a few specific carbohydrate residues are over expressed in cancer cells, which may be an advantage for using a lectin that is specific to such residues. Herein, we report the strategic design of wheat germ agglutinin (WGA) and a fluorescent torch, FITC immobilized on Fe₃O₄ NPs as a cell membrane specific receptor target for breast cancer cells, viz., MCF-7 and MDA-MB-231. The resultant nanocomplexes were well characterized by using microscopy and spectroscopy. The WGA tagged nanocomplex was further loaded with the anticancer drug 5-fluorouracil (5-FU) to selectively kill the cancer cells. The loading efficiency of 5-FU is ∼356 μg mg^-1. The nanocomplex itself shows ∼90% cell viability for all the four cell lines (HEK, HeLa, MCF-7 and MDA-MB-231) studied and is therefore a suitable targeting drug delivery vehicle. However, the nanocomplex loaded with {WGA + 5-FU} shows a ∼1.5-fold decrease in cell viability in the case of specific cells (MCF-7 and MDA-MB-231) when compared to non-specific cells (HeLa and HEK). The internalization of the nanocomplex is supported by fluorescence microscopy and confocal laser scanning microscopy techniques by tracking with the fluorescent torch, FITC. The nanocomplex can be internalized ∼2 times more in the specific cells as compared to the non-specific cells. It is observed that the internalization is ∼2 fold increased when the MDA-MB-231 cells are exposed to a magnetic field for 24 h as compared to in the absence of a magnetic field. Live-dead cell assay of the 5-FU loaded nanocomplex was done by propidium iodide (PI) staining. There is an increase in the cell death by ∼2.5 fold when the cells are under a magnetic field as measured from the PI uptake. Such strategic designing of the nanocomplex can lead to the development of a better method to selectively target and kill the cancer cells by acting as a carrier to deliver a suitable drug, as a result of which the medical field can benefit.

Silica-Calix Hybrid Composite of Allyl Calix[4]arene Covalently Linked to MCM-41 Nanoparticles for Sustained Release of Doxorubicin into Cancer Cells

An inorganic-organic hybrid material, MCM-allylCalix, was synthesized by covalent modification of an MCM-41 surface with a tetra-allyl calixarene conjugate. The synthesized hybrid was characterized by ¹³C and ²⁹Si MAS-NMR, Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller surface area, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) analyses. The application of this MCM-allylCalix hybrid has been demonstrated for loading and in vitro release of doxorubicin (Dox) in phosphate-buffered saline (PBS) buffer as well as in the cancer cells, viz., MCF7, HeLa, and MDA-MB231. The Dox-loaded hybrid, MCM-allylCalix-Dox, was characterized by TEM, FT-IR, TGA, N₂ sorption, diffuse refectance spectroscopy-UV, and fluorescence microscopy to confirm the presence of the drug. The release study of the drug from MCM-allylCalix-Dox was carried out in PBS buffer at pH 5 and 7.4. The results showed ∼140% increase in the release of Dox at pH 5 compared to that at pH 7.4 in 144 h, suggesting a pH-triggered release of the drug. MCM-allylCalix-Dox releases a greater amount of Dox compared to that released from unmodified MCM-Dox. Cytotoxicity studies suggested that MCM-allylCalix-Dox exhibits anticancer activity that is dependent on the nature of the cell. The Dox-loaded hybrid shows more cytotoxicity for MCF7 compared to that for the HeLa and MDA-MB231 cells. This was further supported by ∼120% more internalization of Dox into MCF7 cells compared to that in the other two cell lines. Both fluorescence microscopy and fluorescence-activated cell sorting studies suggested concentration-dependent internalization of Dox into the MCF7 and HeLa cells. The results suggested that the inorganic-organic hybrid can be useful in sustained drug delivery into cancer cells.

Wnt Signaling: Role in Regulation of Haematopoiesis

Hematopoietic stem cells (HSCs) are a unique population of bone marrow cells which are responsible for the generation of various blood cell lineages. One of the significant characteristics of these HSCs is to self-renew, while producing differentiating cells for normal hematopoiesis. Deregulation of self-renewal and differentiation leads to the hematological malignancies. Several pathways are known to be involved in the maintenance of HSC fate among which Wnt signaling is a crucial pathway which controls development and cell fate determination. Wnt signaling also plays a major role in differentiation, self-renewal and maintenance of HSCs. Wnt ligands activate three major pathways including planar cell polarity, Wnt/β-catenin and Wnt/Ca(2+). It has been shown that Wnt/β-catenin or canonical pathway regulates cell proliferation, survival and differentiation in HSCs, deregulation of this pathway leads to hematological malignancies. Wnt non-canonical pathway regulates calcium signaling and planar cell polarity. In this review, we discuss various signaling pathways induced by Wnt ligands and their potential role in hematopoiesis.

Sequence and structural difference favors a distinct preference of Wnt3a binding with co-receptor LRP6

Wnt signaling pathway plays a key role in a wide array of development and physiological processes. Wnt proteins interact with two different co-receptors LRP5/6 and ROR 2, leading to different signal transductions in the cell. Though the Wnt family of proteins has high sequence similarity the specificity for particular co-receptor is not well understood. The choice of pathway is attributed to the binding of Wnt complex to the co-receptor. Our current study is a novel approach using homology modeling, docking, and structural alignment to unravel the structural differences between Wnt3a and Wnt5b binding to LRP6. The conservation of a protruding loop has been identified in Wnt3a protein indicating an enhanced ability of Wnt3a to bind to LRP5/6 against its counter parts. The docking studies have further substantiated the findings. This could potentially help us design and develop novel inhibitors targeting Wnt3a-LRP6 complex in specific tissues or disease states.