Advanced Generation Therapeutics: Biomimetic Nanodelivery System for Tumor Immunotherapy

Tumor immunotherapy is a safe and effective strategy for precision medicine. However, immunotherapy for most cancer cases still ends in failure, with the root causes of the immunosuppressive and extraordinary heterogeneity of the solid tumors microenvironment. The emerging biomimetic nanodelivery system provides a promising tactic to improve the immunotherapy effect while reducing the adverse reactions on nontarget cells. Herein, we summarize the relationship between tumor occurrence and tumor immune microenvironment, mechanism of tumor immune escape, immunotherapy classification (including adoptive cellular therapy, cytokines, cancer vaccines, and immune checkpoint inhibitors) and recommend target cells for immunotherapy first, and then emphatically introduce the recent advances and applications of the latest biomimetic nanodelivery systems (e.g., immune cells, erythrocytes, tumor cells, platelets, bacteria) in tumor immunotherapy. Meanwhile, we separately summarize the application of tumor vaccines. Finally, the predictable challenges and perspectives in a forward exploration of biomimetic nanodelivery systems for tumor immunotherapy are also discussed.

SARS-CoV-2 replicates in the human testis with slow kinetics and has no major deleterious effects ex vivo

IMPORTANCE

SARS-CoV-2 is a new virus responsible for the Covid-19 pandemic. Although SARS-CoV-2 primarily affects the lungs, other organs are infected. Alterations of testosteronemia and spermatozoa motility in infected men have raised questions about testicular infection, along with high level in the testis of ACE2, the main receptor used by SARS-CoV-2 to enter host cells. Using an organotypic culture of human testis, we found that SARS-CoV-2 replicated with slow kinetics in the testis. The virus first targeted testosterone-producing Leydig cells and then germ-cell nursing Sertoli cells. After a peak followed by the upregulation of antiviral effectors, viral replication in the testis decreased and did not induce any major damage to the tissue. Altogether, our data show that SARS-CoV-2 replicates in the human testis to a limited extent and suggest that testicular damages in infected patients are more likely to result from systemic infection and inflammation than from viral replication in the testis.

Utilizing the codon adaptation index to evaluate the susceptibility to HIV-1 and SARS-CoV-2 related coronaviruses in possible target cells in humans

Comprehensive identification of possible target cells for viruses is crucial for understanding the pathological mechanism of virosis. The susceptibility of cells to viruses depends on many factors. Besides the existence of receptors at the cell surface, effective expression of viral genes is also pivotal for viral infection. The regulation of viral gene expression is a multilevel process including transcription, translational initiation and translational elongation. At the translational elongation level, the translational efficiency of viral mRNAs mainly depends on the match between their codon composition and cellular translational machinery (usually referred to as codon adaptation). Thus, codon adaptation for viral ORFs in different cell types may be related to their susceptibility to viruses. In this study, we selected the codon adaptation index (CAI) which is a common codon adaptation-based indicator for assessing the translational efficiency at the translational elongation level to evaluate the susceptibility to two-pandemic viruses (HIV-1 and SARS-CoV-2) of different human cell types. Compared with previous studies that evaluated the infectivity of viruses based on codon adaptation, the main advantage of our study is that our analysis is refined to the cell-type level. At first, we verified the positive correlation between CAI and translational efficiency and strengthened the rationality of our research method. Then we calculated CAI for ORFs of two viruses in various human cell types. We found that compared to high-expression endogenous genes, the CAIs of viral ORFs are relatively low. This phenomenon implied that two kinds of viruses have not been well adapted to translational regulatory machinery in human cells. Also, we indicated that presumptive susceptibility to viruses according to CAI is usually consistent with the results of experimental research. However, there are still some exceptions. Finally, we found that two viruses have different effects on cellular translational mechanisms. HIV-1 decouples CAI and translational efficiency of endogenous genes in host cells and SARS-CoV-2 exhibits increased CAI for its ORFs in infected cells. Our results implied that at least in cases of HIV-1 and SARS-CoV-2, CAI can be regarded as an auxiliary index to assess cells' susceptibility to viruses but cannot be used as the only evidence to identify viral target cells.

Expression of the highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in various types of cells in thymic tissues

Thymus, an important central immune organ in pigs, is the site of T lymphocyte development and maturation and an important target organ for infection and replication of various pathogens. Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) infection results in severe thymic atrophy in piglets. This study aimed to explore the effects of HP-PRRSV on the thymic structure of piglets to elucidate the pathogenesis of thymic atrophy induced by HP-PRRSV. In this study, histopathological techniques and immunofluorescence double staining techniques were used to analyze thymic tissues infected by HP-PRRSV to explore the structural changes of thymus caused by the viral infection and its target cell types. An antibody of cluster of differentiation (CD) 3 (CD3), CD20, CD80, or calgranulin + calprotectin was applied to identify T cells, B cells, dendritic cells (DCs), and macrophages, respectively. The results indicated that a variety of cell components in the thymic tissue were diffusely damaged after viral infection. In the infected thymic tissue, CD80- or calgranulin + calprotectin- -labeled cells supported the HP-PRRSV infection, whereas CD3-labeled T cells and CD20- -labeled B cells did not support the viral infection. The results showed that HP-PRRSV caused the reduction of visible cell components in the thymic tissue, and the virus attacked CD80- and calgranulin + calprotectin-positive cells (such as DCs and macrophages) in the thymic tissue, which played an important role in the pathogenesis of thymus atrophy. These results lay the foundation for elucidating the immunosuppression of piglets after infection with HP-PRRSV.

Retracted: Combined therapy using LHRH-PE40 and anti-CD40 dendritic cells substantially eliminate tumor cells

LHRH-PE40 was used to promote the proliferation of bone marrow derived cell (BMDC) and improve the antigen-presenting ability of BMDC as well as the immune function via the CD40 signal pathway. LHRH-PE40 was also implicated in cancer treatment, targeting a variety of cancer cells that express luteinizing hormone-releasing hormone receptor (LHRHR). In the present study, the mechanism and efficacy of LHRH-PE40 were addressed in the following three aspects. Enzyme-linked immunosorbent assay was performed to confirm the binding specificity of LHRH-PE40 to LHRHR. The killing effect of LHRH-PE40 on target cells was mediated by LHRHR, which specifically killed LHRHR-positive target cells while the minimal cytotoxicity of LHRHR-negative cells is negligible. Spiegelmers, a molecule mutually exclusive with GnRH and developed by Sven Klussmann and Dr Sven Klussmann of NOXXON Pharmaceuticals in Germany, demonstrated that LHRH-PE40 maintains a combinatory characteristics of LHRH and LHRHR. In the end, the mechanism of LHRH-PE40 underlying induction of apoptosis at low concentration and prolonged conditions was firstly demonstrated by the basic method of detecting apoptosis to induce apoptosis. It provided a scientific basis for clinical application of LHRH-PE40 and laid a foundation for the further study of LHRH-PE40 on inducing apoptosis of target cells. The target cells herein refer to tumor cells that overexpress LHRHR. This study shows that activated DC can more effectively promote the proliferation of CD4+ T cells, and initially proved that DC carrying anti-CD40 antibody promoted the immune treatment of the tumor. Combining LHRH-PE40 with anti-CD40 DCs achieved substantially improved efficacy in killing tumor cells.

Barriers of Mucosal Entry of HIV/SIV

Most new HIV infections, over 80%, occur through sexual transmission. During sexual transmission, the virus must bypass specific female and male reproductive tract anatomical barriers to encounter viable target cells. Understanding the generally efficient ability of these barrier to exclude HIV and the precise mechanisms of HIV translocation beyond these genital barriers is essential for vaccine and novel therapeutic development. In this review, we explore the mucosal, barriers of cervico-vaginal and penile tissues that comprise the female and male reproductive tracts. The unique cellular assemblies f the squamous and columnar epithelium are illustrate highlighting their structure and function. Each anatomical tissue offers a unique barrier to virus entry in healthy individuals. Unfortunately barrier dysfunction can lead to HIV transmission. How these diverse mucosal barriers have the potential to fail is considered, highlighting those anatomical areas that are postulated to offer a weaker barrier and are; therefore, more susceptible to viral ingress. Risk factors, such as sexually transmitted infections, microbiome dysbiosis, and high progestin environments are also associated with increased acquisition of HIV. How these states may affect the integrity of mucosal barriers leading to HIV acquisition are discussed suggesting mechanisms of transmission and revealing potential targets for intervention.

Marginal Effects of Systemic CCR5 Blockade with Maraviroc on Oral Simian Immunodeficiency Virus Transmission to Infant Macaques

Current approaches do not eliminate all human immunodeficiency virus type 1 (HIV-1) maternal-to-infant transmissions (MTIT); new prevention paradigms might help avert new infections. We administered maraviroc (MVC) to rhesus macaques (RMs) to block CCR5-mediated entry, followed by repeated oral exposure of a CCR5-dependent clone of simian immunodeficiency virus (SIV) mac251 (SIVmac766). MVC significantly blocked the CCR5 coreceptor in peripheral blood mononuclear cells and tissue cells. All control animals and 60% of MVC-treated infant RMs became infected by the 6th challenge, with no significant difference between the number of exposures (P = 0.15). At the time of viral exposures, MVC plasma and tissue (including tonsil) concentrations were within the range seen in humans receiving MVC as a therapeutic. Both treated and control RMs were infected with only a single transmitted/founder variant, consistent with the dose of virus typical of HIV-1 infection. The uninfected RMs expressed the lowest levels of CCR5 on the CD4⁺ T cells. Ramp-up viremia was significantly delayed (P = 0.05) in the MVC-treated RMs, yet peak and postpeak viral loads were similar in treated and control RMs. In conclusion, in spite of apparent effective CCR5 blockade in infant RMs, MVC had a marginal impact on acquisition and only a minimal impact on the postinfection delay of viremia following oral SIV infection. Newly developed, more effective CCR5 blockers may have a more dramatic impact on oral SIV transmission than MVC.IMPORTANCE We have previously suggested that the very low levels of simian immunodeficiency virus (SIV) maternal-to-infant transmissions (MTIT) in African nonhuman primates that are natural hosts of SIVs are due to a low availability of target cells (CCR5⁺ CD4⁺ T cells) in the oral mucosa of the infants, rather than maternal and milk factors. To confirm this new MTIT paradigm, we performed a proof-of-concept study in which we therapeutically blocked CCR5 with maraviroc (MVC) and orally exposed MVC-treated and naive infant rhesus macaques to SIV. MVC had only a marginal effect on oral SIV transmission. However, the observation that the infant RMs that remained uninfected at the completion of the study, after 6 repeated viral challenges, had the lowest CCR5 expression on the CD4⁺ T cells prior to the MVC treatment appears to confirm our hypothesis, also suggesting that the partial effect of MVC is due to a limited efficacy of the drug. New, more effective CCR5 inhibitors may have a better effect in preventing SIV and HIV transmission.

Induction and Measurement of Cytotoxic T Lymphocyte Activity

Cytotoxic T cells (CTLs) are important immune effector cells in the adaptive immune response. It has been well documented that CTLs are important in host immune responses to viral and bacterial intracellular pathogens, tumors, and transplanted tissues. The properties of CTLs have been studied extensively in murine models, and their roles validated in the human setting. Frequently, the presence of these cells correlates well with protective immunity, so the ability to readily measure the activity of these cells is an important immunological measurement. In this unit, several assays are described that are commonly utilized to induce CTLs and to measure CTL activity both in vitro and in vivo. These assays are adaptable to many experimental and/or disease models, and in the case of the in vitro assays can be applied to measure CTL activity in human samples. © 2018 by John Wiley & Sons, Inc.

The role of S100A4 protein in anticancer cytotoxicity: its presence is required on the surface of CD4+CD25+PGRPs+S100A4+ lymphocyte and undesirable on the surface of target cells

S100A4 is a Ca²⁺-binding protein that performs an important role in metastasis. It is also known for its antitumor functions. S100A4 is expressed by a specialized subset of CD⁴⁺CD²⁵⁺ lymphocytes and is present on those cell's membranes along with peptidoglycan recognition proteins (PGRPs). There, by interacting with major heat shock protein Hsp70, S100A4 plays an important cytotoxic role. The resulting stably formed complex of PGRPs, S100A4 and Hsp70 is required for the identification and binding between a lymphocyte and a target cell. Here, we investigated the S100A4 functions in CD⁴⁺CD²⁵⁺PGRPs⁺S100A4⁺ lymphocyte cytotoxicity against target cells. We demonstrated that those lymphocytes do not form a stable complex with the tumor target cells that themselves have S1004A on their surface. That observation can be explained by our finding that S100A4 precludes the formation of a stable complex between PGRPs, S100A4 (on the lymphocytes' surface), and Hsp70 (on the target cells' surface). The decrease in S100A4 level in CD⁴⁺CD²⁵⁺PGRPs⁺S100A4⁺ lymphocytes inhibits their cytotoxic activity, while the addition of S100A4 in the medium restores it. Thus, the resistance of target cells to CD⁴⁺CD²⁵⁺PGRPs⁺ S100A4⁺ lymphocyte cytotoxicity depends on their S100A4 expression level and can be countered by S100A4 antibodies.

Targeting macrophage necroptosis for therapeutic and diagnostic interventions in atherosclerosis

Atherosclerosis results from maladaptive inflammation driven primarily by macrophages, whose recruitment and proliferation drive plaque progression. In advanced plaques, macrophage death contributes centrally to the formation of plaque necrosis, which underlies the instability that promotes plaque rupture and myocardial infarction. Hence, targeting macrophage cell death pathways may offer promise for the stabilization of vulnerable plaques. Necroptosis is a recently discovered pathway of programmed cell necrosis regulated by RIP3 and MLKL kinases that, in contrast to apoptosis, induces a proinflammatory state. We show herein that necroptotic cell death is activated in human advanced atherosclerotic plaques and can be targeted in experimental atherosclerosis for both therapeutic and diagnostic interventions. In humans with unstable carotid atherosclerosis, expression of RIP3 and MLKL is increased, and MLKL phosphorylation, a key step in the commitment to necroptosis, is detected in advanced atheromas. Investigation of the molecular mechanisms underlying necroptosis showed that atherogenic forms of low-density lipoprotein increase RIP3 and MLKL transcription and phosphorylation-two critical steps in the execution of necroptosis. Using a radiotracer developed with the necroptosis inhibitor necrostatin-1 (Nec-1), we show that (123)I-Nec-1 localizes specifically to atherosclerotic plaques in Apoe (-/-) mice, and its uptake is tightly correlated to lesion areas by ex vivo nuclear imaging. Furthermore, treatment of Apoe (-/-) mice with established atherosclerosis with Nec-1 reduced lesion size and markers of plaque instability, including necrotic core formation. Collectively, our findings offer molecular insight into the mechanisms of macrophage cell death that drive necrotic core formation in atherosclerosis and suggest that this pathway can be used as both a diagnostic and therapeutic tool for the treatment of unstable atherosclerosis.

Facilitating Redundancy-Oriented Management with Gene-Therapy-Oriented Management Against Disaster

This article tests the hypothesis that "if redundancy-oriented management has negative aspects, then it could be facilitated by gene-therapy-oriented management." Negative aspects include disadvantages, misjudgments, or miscalculations. The article provides a newly revised principle of disaster management by studying gene-therapy-oriented management. Based on qualitative analysis, redundancy-oriented and gene-therapy-oriented management are analyzed via five variables: governments, business, volunteers, households, and the international community. The article is valuable because an analytical frame on gene-therapy-oriented management is systematically reconceptualized for the field of disaster management via three elements: unhealthy proteins (problems or failed measures), a vector (new or modified solutions), and target cells (positive outcomes). In accepting the hypothesis, the key tenet is that stakeholders have to assist the progress of redundancy-oriented management with gene-therapy-oriented management by paying attention to the genes of each disaster.

Intracellular events and cell fate in filovirus infection

Marburg and Ebola viruses cause a severe hemorrhagic disease in humans with high fatality rates. Early target cells of filoviruses are monocytes, macrophages, and dendritic cells. The infection spreads to the liver, spleen and later other organs by blood and lymph flow. A hallmark of filovirus infection is the depletion of non-infected lymphocytes; however, the molecular mechanisms leading to the observed bystander lymphocyte apoptosis are poorly understood. Also, there is limited knowledge about the fate of infected cells in filovirus disease. In this review we will explore what is known about the intracellular events leading to virus amplification and cell damage in filovirus infection. Furthermore, we will discuss how cellular dysfunction and cell death may correlate with disease pathogenesis.

Further examination of abscission zone cells as ethylene target cells in higher plants

BACKGROUND AND AIMS

Two aspects of the competence of abscission zone cells as a specific class of hormone target cell are examined. The first is the competence of these target cells to respond to a remote stele-generated signal, and whether ethylene acts in concert with this signal to initiate abscission of the primary leaf in Phaseolus vulgaris. The second is to extend the concept of dual control of abscission cell competence. Can the concept of developmental memory that is retained by abscission cell of Phaseolus vulgaris post-separation in terms of the inductive/repressive control of beta-1,4-glucan endohydrolase (cellulase) activity exerted by ethylene/auxin be extended to the rachis abscission zone cells of Sambucus nigra?

METHODS

Abscission assays were performed using the leaf petiole-pulvinus explants of P. vulgaris with the distal pulvinus stele removed. These (-stele) explants do not separate when treated with ethylene and require a stele-generated signal from the distal pulvinus for separation at the leaf petiole-pulvinis abscission zone. Using these explants, the role of ethylene was examined, using the ethylene action blocker, 1-methyl cyclopropene, as well as the significance of the tissue from which the stele signal originates. Further, leaf rachis abscission explants were excised from the compound leaves of S. nigra, and changes in the activity of cellulase in response to added ethylene and auxin post-separation was examined.

KEY RESULTS

The use of (-stele) explants has confirmed that ethylene, with the stele-generated signal, is essential for abscission. Neither ethylene alone nor the stelar signal alone is sufficient. Further, in addition to the leaf pulvinus distal to the abscission zone, mid-rib tissue that is excised from senescent or green mid-rib tissue can also generate a competent stelar signal. Experiments with rachis abscission explants of S. nigra have shown that auxin, when added to cells post-separation can retard cellulase activity, with activity re-established with subsequent ethylene treatment.

CONCLUSIONS

The triggers that initiate and regulate the separation process are complex with, in bean leaves at least, the generation of a signal (or signals) from remote tissues, in concert with ethylene, a requisite part of the process. Once evoked, abscission cells maintain a developmental memory such that the induction/repression mediated by ethylene/auxin that is observed prior to separation is also retained by the cells post-separation.

Action site of the gene determining susceptibility to propylnitrosourea-induced thymic lymphomas in F344 rats

To clarify whether the determining effect of the thymic lymphoma susceptible-1 (Tls-1) gene is on putative N-propyl-N-nitrosourea (PNU) target cells among T-lineage cells or on other host factors, we investigated the PNU-induced lymphomagenesis in transplantation chimeras between susceptible F344 and resistant LES strain rats. Administration of PNU to lethally irradiated (F344 x LES)F1 rats reconstituted with bone marrow cells from either F344 or LES parental rats invariably led to development of donor-origin thymic lymphomas. On the other hand, thymic lymphomas were induced in thymectomized F1 rats grafted with neonatal LES thymus, of which 4 out of 8 were of the donor origin. These observations indicate that the target cells of thymic lymphomagenesis of F344 and LES rats were equally susceptible to PNU provided they are in susceptible hosts and the LES thymus seems capable of supporting thymic lymphomagenesis, although this capability wanes with aging of the thymus. The effect of the Tls-1 gene, therefore, is neither on PNU susceptibility of the target cells nor on the capability of the thymus to support lymphomagenesis, but on other host factors either in or out of the thymus.

Interruption of the sequential release of small and large molecules from tumor cells by low temperature during cytolysis mediated by immune T-cells or complement

Specific lysis of tumor cells by thymus-derived lymphocytes from alloimmunized mice (T-effector specific lysis) was studied with target cells labeled with isotopes attached to both small ((14)C-labeled nicotinamide) and large ((51)Cr-labeled) molecules. The results confirm and extend previous reports that target cells release small molecules considerably earlier than large molecules during T-effector specific lysis. After interruption of T-effector specific lysis by specific antibody and complement directed against the killer cells, or by ethylenediaminetetraacetic acid, release of both isotopes continued, eventually reaching identical levels of specific release, the value of which represents the fraction of the target cell population which had been committed to die at the time these treatments were applied. On the other hand, release of both isotopes during T-effector specific lysis stops immediately when the cultures are cooled to 0 degrees . Thus, while ethylenediaminetetraacetic acid or specific complement-mediated lysis of the killer cells merely prevents the initiation of any new damage to target cells, cooling to 0 degrees also stops the lytic process in already-damaged target cells. The colloid osmotic phase of target cell lysis induced by specific antibody and complement was similarly stopped at 0 degrees in tumor cells, but not in erythrocytes. Thus, in tumor target cells, both T-effector specific lysis and complement cause a sequential release of progressively larger molecules which can be immediately stopped at any point by cooling to 0 degrees .

Development of cellular immunity in the human fetus: dichotomy of proliferative and cytotoxic responses of lymphoid cells to phytohemagglutinin

The reactivity of cells in vitro was investigated with specimens from various lymphoid organs of seven human fetuses. Thymocytes responded to stimulation by phytohemagglutinin with significant increases in synthesis of DNA, but failed to produce destruction of xenogeneic target cells. In cells from bone marrow, precisely the converse pattern of reactivity to the mitogen was detected. Lymphocytes from spleen and peripheral blood demonstrated both phytohemagglutinin-dependent functions, while hepatic cells did not respond to phytohemagglutinin. Based on the striking dichotomy of phytohemagglutinin-dependent responses in fetal thymocytes and bone-marrow lymphoid cells, we conclude that phytohemagglutinin-dependent cytotoxicity and DNA synthesis are functions of different populations of lymphoid cells during human embryonic development.