Pinning Down Viral Proteins: A New Prototype for Virus–Host Cell Interaction

Pin 1 is an enzyme that specifically catalyzes the cis–trans isomerization of phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif in its substrate proteins. Recent studies demonstrate that stability of several viral proteins is regulated by phosphorylation-dependent prolyl-isomerization by a host factor Pin1. Pin1 is now positioned as an important modulator of the molecular crosstalk between virus and host cells and could be a unique target for anti-virus therapy. This new type of post-translational modification by Pin1 might be involved in the regulation of other viral proteins

The Prolyl Isomerase Pin1 in Breast Development and Cancer

The prolyl isomerase Pin1 specifically isomerizes certain phosphorylated Ser/Thr-Pro bonds and thereby regulates various cellular processes. Pin1 is a target of several oncogenic pathways and is overexpressed in human breast cancer. Its overexpression can lead to upregulation of cyclin D1 and transformation of breast epithelial cells in collaboration with the oncogenic pathways. In contrast, inhibition of Pin1 can suppress the transformation of breast epithelial cells. In addition, Pin1 knockout in mice prevents massive proliferation of breast epithelial cells during pregnancy. Pin1 plays a pivotal role in breast development and may be a promising new anticancer target

Vaccination with Human Induced Pluripotent Stem Cells Creates an Antigen-Specific Immune Response Against HIV-1 gp160

Induced pluripotent stem cells (iPSCs) are artificially derived from somatic cells that have been transduced with defined reprogramming factors. A previous report has indicated the possibility of using iPSCs as an immune stimulator to generate antigen-specific immunity. In our current study, we have investigated whether human iPSCs (hiPSCs) have the ability to enhance specific immune response against a human immunodeficiency virus type 1 (HIV-1) antigen in a xenogenic mouse model. Our results show that BALB/c mice immunized with hiPSCs transduced with an adenoviral vector encoding HIV-1 gp160 exhibited prominent antigen-specific cellular immune responses. We further found that pre-treatment of hiPSCs with ionizing radiation promotes the secretion of pro-inflammatory cytokines such as interleukin-1 alpha (IL-1α), IL-12, and IL-18. These cytokines might promote the activation of antigen-presenting cells and the effective induction of cellular immunity. Our present findings thus demonstrate that a hiPSCs-based vaccine has the potential to generate cellular immunity against viral antigens such as HIV-1 gp160 in a xenogenic condition

Induced cancer stem-like cells as a model for biological screening and discovery of agents targeting phenotypic traits of cancer stem cell

Cancer stem cells (CSCs) retain the capacity to propagate themselves through self-renewal and to produce heterogeneous lineages of cancer cells constituting the tumor. Novel drugs that target CSCs can potentially eliminate the tumor initiating cell population therefore resulting in complete cure of the cancer. We recently established a CSC-like model using induced pluripotent stem cell (iPSC) technology to reprogram and partially differentiate human mammary epithelial MCF-10A cells. Using the induced CSC-like (iCSCL) model, we developed a phenotypic drug assay system to identify agents that inhibit the stemness and self-renewal properties of CSCs. The selectivity of the agents was assessed using three distinct assays characterized by cell viability, cellular stemness and tumor sphere formation. Using this approach, we found that withaferin A (WA), an Ayurvedic medicine constituent, was a potent inhibitor of CSC stemness leading to cellular senescence primarily via the induction of p21Cip1 expression. Moreover, WA exhibited strong anti-tumorigenic activity against the iCSCL. These results indicate that our iCSCL model provides an innovative high throughput platform for a simple, easy, and cost-effective method to search for novel CSC-targeting drugs. Furthermore, our current study identified WA as a putative drug candidate for abrogating the stemness and tumor initiating ability of CSCs

A structural constraint for functional interaction between N-terminal and C-terminal domains in simian immunodeficiency virus capsid proteins

<p>Abstract</p> <p>Background</p> <p>The Gag capsid (CA) is one of the most conserved proteins in highly-diversified human and simian immunodeficiency viruses (HIV and SIV). Understanding the limitations imposed on amino acid sequences in CA could provide valuable information for vaccine immunogen design or anti-HIV drug development. Here, by comparing two pathogenic SIV strains, SIVmac239 and SIVsmE543-3, we found critical amino acid residues for functional interaction between the N-terminal and the C-terminal domains in CA.</p> <p>Results</p> <p>We first examined the impact of Gag residue 205, aspartate (Gag205D) in SIVmac239 and glutamate (Gag205E) in SIVsmE543-3, on viral replication; due to this difference, Gag_206-216(IINEEAADWDL) epitope-specific cytotoxic T lymphocytes (CTLs) were previously shown to respond to SIVmac239 but not SIVsmE543-3 infection. A mutant SIVmac239, SIVmac239Gag205E, whose Gag205D is replaced with Gag205E showed lower replicative ability. Interestingly, however, SIVmac239Gag205E passaged in macaque T cell culture often resulted in selection of an additional mutation at Gag residue 340, a change from SIVmac239 valine (Gag340V) to SIVsmE543-3 methionine (Gag340M), with recovery of viral fitness. Structural modeling analysis suggested possible intermolecular interaction between the Gag205 residue in the N-terminal domain and Gag340 in the C-terminal in CA hexamers. The Gag205D-to-Gag205E substitution in SIVmac239 resulted in loss of in vitro core stability, which was recovered by additional Gag340V-to-Gag340M substitution. Finally, selection of Gag205E plus Gag340M mutations, but not Gag205E alone was observed in a chronically SIVmac239-infected rhesus macaque eliciting Gag_206-216-specific CTL responses.</p> <p>Conclusions</p> <p>These results present in vitro and in vivo evidence implicating the interaction between Gag residues 205 in CA NTD and 340 in CA CTD in SIV replication. Thus, this study indicates a structural constraint for functional interaction between SIV CA NTD and CTD, providing insight into immunogen design to limit viral escape options.</p

Microfluidic Device for Simple Diagnosis of Plant Growth Condition by Detecting miRNAs from Filtered Plant Extracts

植物の生育状態を野外で早期診断できる装置を開発〜ストレスに応答して生じるmiRNAを葉から検出〜.京都大学プレスリリース. 2024-04-04.Plants are exposed to a variety of environmental stress, and starvation of inorganic phosphorus can be a major constraint in crop production. In plants, in response to phosphate deficiency in soil, miR399, a type of microRNA (miRNA), is up-regulated. By detecting miR399, the early diagnosis of phosphorus deficiency stress in plants can be accomplished. However, general miRNA detection methods require complicated experimental manipulations. Therefore, simple and rapid miRNA detection methods are required for early plant nutritional diagnosis. For the simple detection of miR399, microfluidic technology is suitable for point-of-care applications because of its ability to detect target molecules in small amounts in a short time and with simple manipulation. In this study, we developed a microfluidic device to detect miRNAs from filtered plant extracts for the easy diagnosis of plant growth conditions. To fabricate the microfluidic device, verification of the amine-terminated glass as the basis of the device and the DNA probe immobilization method on the glass was conducted. In this device, the target miRNAs were detected by fluorescence of sandwich hybridization in a microfluidic channel. For plant stress diagnostics using a microfluidic device, we developed a protocol for miRNA detection by validating the sample preparation buffer, filtering, and signal amplification. Using this system, endogenous sly-miR399 in tomatoes, which is expressed in response to phosphorus deficiency, was detected before the appearance of stress symptoms. This early diagnosis system of plant growth conditions has a potential to improve food production and sustainability through cultivation management

Recapitulation of hepatitis B virus–host interactions in liver organoids from human induced pluripotent stem cells

Therapies against hepatitis B virus (HBV) have improved in recent decades; however, the development of individualized treatments has been limited by the lack of individualized infection models. In this study, we used human induced pluripotent stem cell (hiPSC) to generate a functional liver organoid (LO) that inherited the genetic background of the donor, and evaluated its application in modeling HBV infection and exploring virus–host interactions. To establish a functional hiPSC-LO, we cultured hiPSC-derived endodermal, mesenchymal, and endothelial cells with a chemically defined medium in a three-dimensional microwell culture system. Based on cell-cell interactions, these cells could organize themselves and gradually differentiate into a functional organoid, which exhibited stronger hepatic functions than hiPSC derived hepatic like cell (HLC). Moreover, the functional LO demonstrated more susceptibility to HBV infection than hiPSC-HLC, and could maintain HBV propagation and produce infectious virus for a prolonged duration. Furthermore, we found that virus infection could cause hepatic dysfunction of hiPSC-LOs, with down-regulation of hepatic gene expression, induced release of early acute liver failure markers, and altered hepatic ultrastructure. Therefore, our study demonstrated that HBV infection in hiPSC-LOs could recapitulate virus life cycle and virus induced hepatic dysfunction, suggesting that hiPSC-LOs may provide a promising individualized infection model for the development of individualized treatment for hepatitis