All Articles

Anna E. D’Amico¹ and Michelle R. Lennartz^1*

¹Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Avenue Albany, NY 12208, USA

During phagocytosis, internal membranes are recruited to the site of pathogen binding and fuse with the plasma membrane, providing the membrane needed for pseudopod extension and target uptake. The mechanism by which vesicles destined for the phagosome are generated, targeted, and fuse is unknown. We established that Golgi-associated protein kinase C-epsilon (PKC-ε) is necessary for the addition of membrane during FcγR -mediated phagocytosis. PKC-ε is tethered to the Golgi through interactions between its’ regulatory domain and the Golgi lipids PI4P and diacylglycerol; disruption of these interactions prevents PKC-ε concentration at phagosomes and decreases phagocytosis. The accumulated evidence suggests that PKC-ε orchestrates vesicle formation at the Golgi by a mechanism requiring lipid binding but not enzymatic activity. This review discusses how PKC-ε might mediate vesicle formation at the level of budding and fission. Specifically, we discuss PKC-ε binding partners, the formation of lipid subdomains to generate membrane curvature, and PKC-ε mediated links to the actin and microtubule cytoskeleton to provide tension for vesicle fission. Assimilating information from several model systems, we propose a model for PKC-ε mediated vesicle formation for exocytosis during phagocytosis that may be applicable to other processes that require directed membrane delivery and fusion.

Manuel Freire^1*, Pablo Barbeito¹, Concepción S. Sarandeses¹, Cristina Díaz-Jullien¹, Juan Muras¹, Guillermo Covelo¹, David Moreira¹ and Carmen Freire-Cobo¹

¹The Department of Biochemistry and Molecular Biology, CIBUS, Faculty of Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

Prothymosin α (ProTα) is a 109-11 amino acid protein widely distributed in mammalian tissues and particularly abundant in lymphoid cells. Genomic and proteomic studies led to consider ProTα as a multifunctional protein implicated in nuclear and cytoplasmic functions. The nuclear function of ProTα is related to chromatin activity through its interaction with core histones and proteins involved in chromatin remodelling, whereas, processes related to the phosphorylation, the proteolytic processing to generate Thymosin α1, and the role as anti-apoptotic factor of ProTα, are linked to its cytoplasmic location. Affinity chromatography and co-immunoprecipitation experiments have demonstrated novel interactions of ProTα with acidic proteins such as SET, ANP32A, and ANP32B in the cytoplasm of proliferating lymphocytes. The stabilization of these interactions by chemical cross-linking with formaldehyde shows that they are formed through associations in six acidic complexes which correspond to selective interactions of SET and ANP32 proteins with ProTα. These ProTα-complexes also include cytoplasmic proteins implicated in membrane remodelling and in mitochondrial activity. In conclusion, these novel protein interactions of ProTα observed in proliferation activity and apoptosis studies, suggest that they might be related to mechanisms involved in the proliferation activity and the apoptotic control of lymphocytes.

Melissa Ellermann¹ and R. Balfour Sartor^{2, 3, 4*}

¹Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.

²Departments of Medicine, University of North Carolina, Chapel Hill, NC, USA.

³Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, USA.

⁴Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC, USA.

Host-associated microbial communities modulate numerous aspects of host physiology at the epithelial interface within mucosal environments. Perturbations to this symbiotic relationship between host and microbiota has been linked to numerous microbial-driven pathological states, including Crohn’s disease (CD). This is in part driven by the outgrowth of aggressive resident bacterial strains such as adherent and invasive Escherichia coli (AIEC) and changes in bacterial physiology and function that promote enhanced mucosal association of pathobionts and aberrant stimulation of mucosal immunity. Endogenous bacteria from host-associated microbial communities can adopt a sessile lifestyle and form multicellular structures known as biofilms that are generated through the expression of extracellular adhesion factors that include curli amyloid fibrils, cellulose and type 1 pili. In addition to enabling bacterial attachment to mucosal surfaces, biofilm components also stimulate immune responses and can therefore instigate or perpetuate microbial-driven inflammatory diseases such as CD. These host-bacterial interactions provide pharmacological targets that can potentially be exploited to limit mucosal adherence of aggressive enteric bacteria, inappropriate stimulation of inflammatory immune responses and consequent development of chronic intestinal inflammation.

Sreeparna Chakraborty¹ & Gaurisankar Sa^1*

¹Division of Molecular Medicine, Bose Institute, P-1/12, Calcutta Improvement Trust Scheme VII M, Kolkata 700054, India

Modulation of immune cells to rejuvenate the immune responses against cancer becomes a promising strategy for cancer therapy. T-regulatory cells are one of the major hurdles in successful cancer immunotherapy. Recent studies discovered that apart from CD4⁺ Treg cells, CD8⁺ Tregs also play roles in tumor immune evasion. Moreover, CD8⁺ Tregs shows synergistic immunosuppression with CD4⁺ Treg cells in tumor microenvironment. Several phenotypic markers have been described for peripherally induced CD8⁺ Treg cells, but till now no universal phenotypic signature has yet established. FOXP3 is the master regulator of Treg cells and its transcription is critically regulated by promoter region as well as three intronic conserved non-coding regions, viz; CNS 1, 2 and 3. In this review, we have described the transcriptional networking associated with the regulation of FOXP3 in tumor-CD8⁺ Treg cells along with CD4⁺ nTreg and iTreg cells. Intervention of the intensive transcriptional machinery of FOXP3 regulation may aid to target Treg cells and thus could potentiate immunotherapy of cancer.

José M. Serra López-Matencio¹, Concepción Martínez Nieto¹, Alberto Morell Baladrón¹, Santos Castañeda^2*

¹Hospital Pharmacy Service, Hospital de la Princesa, IIS-Princesa, c / Diego de León 62; 28006-Madrid, Spain

²Rheumatology Service, Hospital de la Princesa, IIS-Princesa, c / Diego de León 62; 28006-Madrid, Spain

Biological agents are used to treat a variety of diseases in many therapeutic areas, including oncology, hematology, rheumatology, gastroenterology, dermatology, neurology, respiratory diseases, hormone deficiency and infections. Since biologics constitute many of the recently approved new therapies, clinical research of drug-drug interactions with biologics has been discussed. Here, we present a personal view of drug-drug interactions with monoclonal antibodies, a predominant class of therapeutic biologics. In this line, we think that the interactions of biological agents with other chemical drugs represent an important issue, completely unknown and with potentially prominent clinical implications, that will have to be taken into account in coming years.

Kelly Gibas^1*

¹Department of Human Kinetics and Applied Health Science, 3900 Bethel Drive, Bethel University, MN, USA

The emerging bioenergetic model for cognitive decline defines late-onset, neural impairment as symptomatic of brain starvation resulting from the physiological paradox of chronic cerebral hyperinsulinemia/hyperglycemia concurrent with episodic hypoglycemia. The catabolic injury to the brain occur linear to energy deficits and mirror the progression of peripheral, cellular insulin resistance and type II diabetes; this pathology of brain starvation is being recognized as Type III diabetes. An energetic construct of neurodegeneration centers on homeostatic energy failure, as hypothesized by Demetrius and Simon (2012)¹; the model focuses on the centralized role of astrocytes for the metabolic coupling of lactate to feed hungry neurons. Healthy fed/fasted signaling within the cells of the brain involves coordinated action of astrocytes and neurons. The astrocytes’ primary mode of energy production, via brain-side, glucose transporter 1 (GLUT1), is glycolysis; glucose is metabolized anaerobically to lactate. Lactate is released by the astrocyte into the extracellular milieu and utilized as supplemental energy for neurons² (Pellerin, 2007). A recent study, “PSEN1 Mutant iPSC-Derived Model Reveals Severe Astrocyte Pathology in Alzheimer’s Disease,” published in Stem Cell Reports (2017)³ by a team from the University of Eastern Finland confirmed the role of astrocytes as lactate shuttles3. This study was the first to use human stem cells to demonstrate that in patients with AD astrocytes manifest pathological metabolic shifts. Conclusions of the study show astrocytes play a significant role in the early stages of the disease and contribute to metabolic changes in neurons leading to neurodegenerative pathology.

Laura Comi^1*, Elisa Di Filippo¹, Franco Maggiolo¹

¹Division of Infectious Diseases, ASST Papa Giovanni XXIII, Bergamo, Italy

Introduction: The use of combination antiretroviral therapy (cART) containing three active drugs from at least two different classes is the standard of care for HIV treatment worldwide. The availability of newer drugs with improved potency and tolerability and higher barrier to the development of resistance allows exploring the feasibility of ARV-sparing strategies, namely dual therapies. A dual therapy based on dolutegravir plus lamivudine could be an intriguing simplification strategy for individuals with stable HIV suppression on cART.

Results: Seven studies of dual therapy regimens based on dolutegravir plus lamivudine were critiqued. All of them report a low rate of therapeutic failure due to any cause and a small number of virologic failures. More important virologic failures were not associated with loss of future option as no resistance inducing mutation to ongoing drugs emerged. On the safety side, after the switch, very few short-term adverse events leading to treatment discontinuation were observed and surrogate markers of long term toxicities such as changes in lipid profile and renal function were minimally influenced or improved.

Discussion: Dolutegravir plus lamivudine as a switch option in patients with sustained viral control is still to be considered an experimental approach. Although small in number and heterogeneous in nature the studies that evaluated the effectiveness of dolutegravir plus lamivudine dual therapy have documented substantial virologic efficacy and tolerability of the regimen without exposing patients to the risk of selecting for INSTI-inducing resistance mutations.

Xiaofeng Ding¹, Shuanglin Xiang^1*

¹Key Laboratory of Protein Chemistry and Development Biology of State Education Ministry of China, College of Life Science, Hunan Normal University, Changsha, P.R. China

Endocytosis is critical for normal cellular function through clearing foreign materials and protecting the host from pathogen/virus attack. Innate immune cells play important roles in specifically recognizing and degrading microbes by generating phagosomes and phagolysosomes. However, the knowledge of how innate immunity regulates endocytosis in vitro and in vivo remains limited. In this review, we attempt to systematically and comprehensively summarize our current understanding of endocytosis and the role of Rab GTPases in the innate immune system. Understanding the immunity mechanisms of endocytosis might help develop targeted therapeutics for various applications, including viral inactivation and clearance, pathogen removal and even adjuvant-enhanced antibody responses.

Diego Salas-Benito^1,2, Noelia Casares^2,3, Pablo Sarobe^2,3, Juan José Lasarte^2,3 and Sandra Hervas-Stubbs^2,3*

¹Oncology Department, University Clinic, University of Navarra, Spain.

²Instituto de Investigación Sanitaria de Navarra (IdISNA), Spain.

³Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Spain.

Zulfia Hussain¹, Junaid Ali Khan^1*

¹Institute of Pharmacy, Physiology and Pharmacology, University of Agriculture Faisalabad (UAF)-38040, Pakistan

Kara D. Capriotti^1,2*

¹Veloce BioPharma LLC, 1007 N Federal Hwy #E4, Fort Lauderdale, FL 33304

²Bryn Mawr Skin and Cancer Institute, 919 Conestoga Road, Building 2, Suite 106, Rosemont, PA 19010

Fatemah Salem Basingab^1,2 and David John Morgan^1*

¹Department of Cellular and Molecular Medicine, University of Bristol, School of Biomedical Sciences, University Walk, Bristol BS8 1TD, UK.

²Department of Biology, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21589, Kingdom of Saudi Arabia

Tumour-infiltrating cytotoxic T lymphocytes (CTLs) play a key role in tumour killing. However, many cancers adopt various strategies to induce immunosuppression. Priming of naïve CD8⁺ T cells to become CTLs occurs via cognate interactions of the T cell receptor (TcR) and CD28 with tumour-derived peptide epitopes expressed on major histocompatibility complex (MHC) class I molecules and CD80/CD86 on T cells and antigen-presenting cells (APCs) respectively. Here we report that, in the absence of CD80/CD86 expression by renal carcinoma (Renca) cells, expression of intercellular adhesion molecule-1 (ICAM-1) by Renca cells provides a potent alternative co-stimulation to a tumour-specific CD8⁺ T cells causing them to produce interferon gamma (IFN-γ) which is crucial for the further up-regulation of ICAM-1 on tumour cells. We have shown that overexpression of cyclooxygenase-2 (COX-2), by Renca cells (Renca-T3), results in increased levels of prostaglandin (PG) E₂ production, which can directly suppress anti-tumour CD8⁺ T cells resulting in loss of CTL function in vivo and cause metastases to the tumor-draining lymph nodes (TDLNs). Significantly, our data also show that overexpression of ICAM-1 on Renca-T3 cells can counteract the immune-suppressive effect of PGE₂ and restore CTL responses.

Enrico Bracco^2*, Cristina Panuzzo¹, Barbara Pergolizzi^1*

¹Dept. of Clinical & Biological Sciences, University of Turin, Italy

²Dept. of Oncology, University of Turin, Italy

HECT ubiquitin ligases are key components of the eukaryotic ubiquitin-proteasome system controlling different cellular physiological aspects as well as the genesis of several human diseases. Among the HECT family, the HERC subfamily members are characterized by having one or more RCC1-like domains, a C-terminal HECT domain and the molecular mass ranging approximately from 120 kDa to 500 kDa. Due to their large size, some of them are refractory to functional characterization. We have recently identified and functionally characterized a novel large HECT member in Dictyostelium discoideum that, in many aspects, exhibits structural similarities with the mammalian large HERC1. In the present minireview, we shortly summarize and revise the current phylogenetic history of HERC proteins among the different living organisms.

Manuela M Almo¹, Isabel G Sousa², Andréa Q Maranhão^2,3, Marcelo M Brigido^2,3*

¹Molecular Pathology Graduation Program, Medicine Faculty, University of Brasilia, Brasilia, Brazil

²Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, Brazil

³Institute for Immunology Investigation, a National Institute of Science and Technology

Long noncoding RNAs (lncRNAs) are regulatory RNA molecules that are involved in various biological processes. In the immune system, the lncRNAs play important roles in development, differentiation, survival, cell fate determination, proliferation and activation of immune cells. Lymphocytes are the main players of the adaptive immunity and CD3+ T cells acts as a master regulator for the immune responses. These cells following activation by antigens and co-stimulatory signals are differentiated into various effector T cell subsets, including CD4 and CD8 T cells. These heterogeneous populations can be distinguished based on molecular surface markers and subsets of these markers can be used to denote various stages of T lymphocyte differentiation, notwithstanding the CD3⁺ T cells phenotypes are markedly influenced by lncRNAs. In the present review, we summarize recent research on the role of long noncoding RNAs in subtypes of CD4⁺ and CD8⁺ human T cells.

Marek Adamowicz^1*

¹Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK.

ATM kinase is a master regulator of the DNA damage response (DDR). A recently published report from the d’Adda di Fagagna laboratory¹ sheds a light onto our understanding of ATM activation. In this short-commentary we will expand on this and other work to perceive better some of the aspects of ATM regulation.

Nicholas L. Cianciola^a,d and Cathleen R. Carlin^a,b,*

^aDepartments of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106

^bThe Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106

^dThe Lockwood Group, Stamford, CT 06901

The interplay between viruses and host factors regulating inflammatory or cytotoxic responses directed against infected cells is well documented. Viruses have evolved a wide array of mechanisms that strike a balance between the elimination of virus and immune-mediated tissue injury by antiviral immune responses. The topic of this mini-review is a series of recent studies demonstrating a link between cholesterol trafficking and innate immune responses in cells infected with human adenoviruses that provide the backbone of commonly used vectors in gene medicine. Besides revealing an unexpected role for lipid metabolism in immune evasion, these studies have important implications for understanding the molecular basis of cholesterol trafficking in normal cells and various disease states. They also describe a previously unappreciated host-virus interaction that may be employed by other pathogens to interfere with the host innate immune system.

Sarah Alter¹, Peter R. Rhode¹, Emily K. Jeng¹, and Hing C. Wong^1*

¹Altor BioScience, Miramar, Florida

This mini review provides an overview and rationale for creating IL-15-based fusion protein complexes to be used as targeted immunotherapeutic agents. IL-15 stimulates proliferation and activation of CD8+ T and natural killer cells which result in augmentation of their anti-tumor activities. We have created ALT-803, an IL-15 superagonist complex which exhibits longer serum half-life, longer retention in lymphoid tissues, and better immunostimulatory and anti-tumor activities compared to native IL-15. When used alone or in combination with other immunotherapeutic molecules in various mouse tumor models, ALT-803 effectively reduces tumor burden and prolongs survival by stimulating the innate and adaptive arms of the immune system. To evaluate whether ALT-803 could be used as a protein scaffold to create IL-15-based tumor cell-specific molecules, we genetically fused it with a single chain anti-CD20 antibody derived from the variable regions of rituximab. This novel fusion protein exhibits enhanced anti-tumor activity compared to rituximab while maintaining IL-15 immunostimulating properties. Thus, ALT-803 may be exploited as a versatile scaffold to produce multivalent targeted fusion proteins to improve the anti-tumor efficacy of other therapeutic agents in the clinic.

Laura Pulze¹, Miriam Capri², Annalisa Grimaldi¹, Stefano Salvioli², Gianluca Tettamanti¹, Magda de Eguileor^1*

¹University of Insubria, Department of Biotechnology and Life Sciences, 21100 Varese, Italy

²University of Bologna, Department of Experimental, Diagnostic and Specialty Medicine (DIMES), 40126 Bologna, Italy

W. Jean Dodds^1*

¹Hemopet, 938 Stanford Street, Santa Monica, California 90403, USA

Tuan Vo-Dinh*¹, Yang Liu¹, Bridget M Crawford¹, Hsin-Neng Wang¹, Hsiangkuo Yuan¹, Janna K Register¹, Christopher G Khoury¹

¹Fitzpatrick Institute for Photonics, Department of Biomedical Engineering, Department of Chemistry, Duke University, Durham, NC 27708-0281, USA

Cancer has been a significant threat to human health with more than eight million deaths each year in the world. There is an urgent need to develop novel methods to improve cancer management. Biocompatible gold nanostars (GNS) with tip-enhanced electromagnetic and optical properties have been developed and applied for multifunctional cancer diagnostics and therapy (theranostics). The GNS platform can be used for multiple sensing, imaging and treatment modalities, such as surface-enhanced Raman scattering, two-photon photoluminescence, magnetic resonance imaging and computed tomography as well as photothermal therapy and immunotherapy. GNS-mediated photothermal therapy combined with checkpoint immunotherapy has been found to reverse tumor-mediated immunosuppression, leading to the treatment of not only primary tumors but also cancer metastasis as well as inducing effective long-lasting immunity, i.e. an anticancer ‘vaccine’ effect.

Kao-Pin Hwang^1*, Ting-Yu Yen¹

Bettina Sehnert^1*, Harald Burkhardt², Stefan Dübel³, Reinhard E. Voll¹

The activation of intracellular signaling pathways such as the classical nuclear factor kappaB (NF-kappaB) pathway is related to the pathogenesis of several inflammatory autoimmune diseases including rheumatoid arthritis (RA). To clarify the role of disease-relevant cell-types and signaling molecules in vitro or in vivo, it is necessary to target them selectively without disturbing the homeostasis of the immune system. We developed sneaking ligand fusion proteins (SLFPs) for cell-type specific modulation of signaling pathways. We designed the first SLFPs to inhibit the activation of NF-kappaB, a key regulator of inflammation, solely in the activated endothelium. Our “sneaking ligand” NF-kappaB inhibitor (named SLC1) inhibits NF-kappaB activation specifically in E-selectin expressing cells in vitro and in mouse models of arthritis indicating the importance of NF-kappaB in the activated endothelium. Clinical signs of arthritis were ameliorated by SLC1 treatment. We conclude that the SLFP architecture consisting of easily exchangeable domains represents an attractive approach to utilize other disease-relevant biological targets both on the cell surface and intracellularly. By relying on two independent disease specific targets, SLFPs may increase the therapeutic efficacy and reduce adverse effects.

Asylkhan Rakhymzhan^1*, Randall L. Lindquist^1*, Anja E. Hauser^1,2#, Raluca Niesner^1#

In the last two decades intravital multi-photon imaging has become a central tool to investigate cellular and molecular dynamics of immune reactions in vivo. Currently, challenges in exploiting the full power of this technology include limitations on the number of simultaneously detectable parameters as well as in expanding the acquisition in time and space. Here we discuss technological advancements developed in order to overcome these challenges and focus on the example of germinal center reactions as multi-parametric immunological processes evolving over a time course of days and weeks.

Millet Treinin*

The nicotinic acetylcholine receptor (nAChR) gene family encodes for subunits of acetylcholine gated ion channels. These receptors are expressed widely and have many functions including anti-inflammatory effects mediated by the α7 nAChR, as part of the cholinergic anti-inflammatory pathway, in immune cells, microglia and astrocytes. Maturation of α7 nAChRs into functional ligand-gated ion channels in the plasma membrane is a complex process likely to require the RIC-3 protein. This endoplasmic reticulum resident chaperone affects maturation of multiple nAChRs, but its interaction with these receptors and its effects on their maturation differ for different nAChRs. Moreover, these interactions and effects are regulated by multiple mechanisms. Genetic analysis has implicated RIC-3 in the neuroinflammatory disease Multiple Sclerosis (MS), and in the neurodegenerative Parkinson's disease (PD). Neuroinflammation contributes to the progression of neurodegenerative diseases including PD. This information combines to suggest that RIC-3 may contribute to progression of both MS and PD via its effects on the α7 nAChR and the cholinergic anti-inflammatory pathway. Furthermore, we suggest that mechanisms regulating RIC-3 expression and activity may have a role in controlling inflammation.

Julie D. Saba*

After undergoing positive and negative selection in the thymus, surviving mature T cells egress from the thymic parenchyma and enter the bloodstream to participate in adaptive immunity. Thymic egress requires signals mediated by sphingosine-1-phosphate (S1P), a bioactive lipid that serves as the ligand for a family of G protein-coupled receptors (S1P1-5) expressed on many cell types, including T cells. In the final stage of their development, T cells upregulate S1P1 expression on the cell surface, which enables them to recognize and respond to a chemotactic S1P gradient that lures them into the bloodstream. The gradient is generated by an S1P source close to the site of egress combined with an S1P sink generated by the actions of S1P catabolic enzymes including S1P lyase (SPL), the only enzyme that irreversibly degrades S1P. The requisite contribution of SPL to thymic egress is demonstrated by the profound lymphopenia observed in SPL knockout (KO) mice and wild type mice treated with SPL inhibitors. SPL is robustly expressed in thymic epithelial cells (TECs), which make up the stromal reticular network of the thymus. However, TEC SPL was recently found to be dispensable for thymic egress. In contrast, deletion of SPL in dendritic cells (DCs) — which represent only a small percent of thymic stroma — disrupts the S1P gradient and blocks thymic egress. These recent observations identify DCs as homeostatic regulators of thymic export through the actions of SPL, thereby adding one more piece to the complex puzzle of how S1P signaling contributes to the regulation of T cell trafficking.