Innate immune activation by macrophages is an essential part of host defence against infection. Cytosolic recognition of microbial DNA in macrophages leads to induction of interferons and cytokines ...through activation of cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING). Other host factors, including interferon-gamma inducible factor 16 (IFI16), have been proposed to contribute to immune activation by DNA. However, their relation to the cGAS-STING pathway is not clear. Here, we show that IFI16 functions in the cGAS-STING pathway on two distinct levels. Depletion of IFI16 in macrophages impairs cGAMP production on DNA stimulation, whereas overexpression of IFI16 amplifies the function of cGAS. Furthermore, IFI16 is vital for the downstream signalling stimulated by cGAMP, facilitating recruitment and activation of TANK-binding kinase 1 in STING complex. Collectively, our results suggest that IFI16 is essential for efficient sensing and signalling upon DNA challenge in macrophages to promote interferons and antiviral responses.
A biosimilar drug is defined in the US Food and Drug Administration (FDA) guidance document as a biopharmaceutical that is highly similar to an already licensed biologic product (referred to as the ...reference product) notwithstanding minor differences in clinically inactive components and for which there are no clinically meaningful differences in purity, potency, and safety between the two products. The development of biosimilars is a challenging, multistep process. Typically, the assessment of similarity involves comprehensive structural and functional characterization throughout the development of the biosimilar in an iterative manner and, if required by the local regulatory authority, an in vivo nonclinical evaluation, all conducted with direct comparison to the reference product. In addition, comparative clinical pharmacology studies are conducted with the reference product. The approval of biosimilars is highly regulated although varied across the globe in terms of nomenclature and the precise criteria for demonstrating similarity. Despite varied regulatory requirements, differences between the proposed biosimilar and the reference product must be supported by strong scientific evidence that these differences are not clinically meaningful. This review discusses the challenges faced by pharmaceutical companies in the development of biosimilars.
Biosimilars have the potential to provide lower cost alternatives and increase access to biologic medicines. Biosimilars are evaluated based on the “totality of evidence” including comprehensive analytical data, limited nonclinical studies, comparative clinical pharmacokinetic/pharmacodynamic, safety and efficacy data, to ensure patients receive high quality, safe and effective medicines. Kirchhoff and coworkers highlight the challenges faced during the development of biosimilars, and the range of state‐of‐the‐art analytical tools that are used to assess similarity.
Glia: the fulcrum of brain diseases Giaume, C; Kirchhoff, F; Matute, C ...
Cell death and differentiation,
07/2007, Letnik:
14, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Neuroglia represented by astrocytes, oligodendrocytes and microglial cells provide for numerous vital functions. Glial cells shape the micro-architecture of the brain matter; they are involved in ...information transfer by virtue of numerous plasmalemmal receptors and channels; they receive synaptic inputs; they are able to release 'glio'transmitters and produce long-range information exchange; finally they act as pluripotent neural precursors and some of them can even act as stem cells, which provide for adult neurogenesis. Recent advances in gliology emphasised the role of glia in the progression and handling of the insults to the nervous system. The brain pathology, is, to a very great extent, a pathology of glia, which, when falling to function properly, determines the degree of neuronal death, the outcome and the scale of neurological deficit. Glial cells are central in providing for brain homeostasis. As a result glia appears as a brain warden, and as such it is intrinsically endowed with two opposite features: it protects the nervous tissue as long as it can, but it also can rapidly assume the guise of a natural killer, trying to eliminate and seal the damaged area, to save the whole at the expense of the part.
Development of Biosimilars AL-Sabbagh, Ahmad, MD; Olech, Ewa, MD; McClellan, Joseph E., PhD, MBA ...
Seminars in arthritis and rheumatism,
04/2016, Letnik:
45, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Objective To provide an overview of the underlying scientific principles and standards for developing a biosimilar product. Methods An Internet-based literature search through June 2015 was performed ...for information related to biosimilar manufacturing and development, including a review of regulatory guidelines and requirements. Results Biologics, both biosimilars and their corresponding reference products, are complex molecules produced by biotechnology in living systems. The development of biologics involves multiple levels of intricate, highly controlled manufacturing processes, combined with preclinical structural, functional, and biological assessments, as well as clinical efficacy and safety, including immunogenicity, analyses. In addition, to ensure a high degree of similarity, a biosimilar must undergo a comparability exercise at every step of its development, as outlined by regulatory agencies, to demonstrate that potential differences from the reference product are not clinically meaningful with regard to quality, safety, and efficacy (European Medicines Agency EMA) or safety, purity, and potency (US Food and Drug Administration FDA). At the foundation of the biosimilar development process lays the establishment of a high degree of structural similarity with its reference product. State-of-the-art technologies must be employed to demonstrate a high degree of structural and functional similarity. Finally, clinical pharmacokinetic and pharmacodynamic as well as clinical efficacy and safety similarity must be confirmed between biosimilar and originator. Regulators, including the FDA and the EMA consider the totality of the evidence from this comprehensive step-wise comparative similarity exercise in its determination of biosimilarity for licensing. Conclusions The rigorous and highly regulated processes required to develop a biosimilar have been designed as such to establish a high degree of biosimilarity with a reference product in terms of the structural, functional, biological, and clinical attributes.
More than a decade ago it was established that intact nef genes are critical for efficient viral persistence and greatly accelerate disease progression in SIVmac-infected rhesus macaques and in ...HIV-1-infected humans. Subsequent studies established a striking number of Nef functions that evidently contribute to the maintenance of high viral loads associated with the development of immunodeficiency in the 'evolutionary-recent' human and the experimental macaque hosts. Recent data show that many Nef activities are conserved across different lineages of HIV and SIV. However, some differences also exist. For example, Nef alleles from most SIVs that do not cause disease in their natural monkey hosts, but not those of HIV-1 and its simian precursors, down-modulate TCR-CD3 to suppress T cell activation and programmed death. This evolutionary loss of a specific Nef function may contribute to the high virulence of HIV-1 in humans.
Accumulating evidence shows that several cell types have the capacity to secrete membrane proteins by incorporating them into exosomes, which are small lipid vesicles derived from the intralumenal ...membranes of multivesicular bodies (MVBs) of the endocytic pathway. Exosomes are expelled in the extracellular space upon fusion of the MVB with the plasma membrane. Exosomal release is a way of secreting membrane proteins meant to be discarded, or to be passed on to other cells. Here, we demonstrate, using primary cortical cultures, that neurones and astrocytes can secrete exosomes. We find that exosomes released by cortical neurones contain the L1 cell adhesion molecule, the GPI-anchored prion protein, and the GluR2/3 but not the NR1 subunits of glutamate receptors. We also show that exosomal release is regulated by depolarisation. Our observation suggests that exosomes may have a regulatory function at synapses and could also allow intercellular exchange of membrane proteins within the brain.
Bleeding from brainstem cavernomas may cause severe deficits due to the absence of non-eloquent nervous tissue and the presence of several ascending and descending white matter tracts and nerve ...nuclei. Surgical removal of these lesions presents a challenge to the most surgeons. The authors present their experience with the surgical treatment of 43 patients with brainstem cavernomas. Important aspects of microsurgical anatomy are reviewed. The surgical management, with special focus on new intraoperative technologies as well as controversies on indications and timing of surgery are presented. According to several published studies the outcome of brainstem cavernomas treated conservatively is poor. In our experience, surgical resection remains the treatment of choice if there was previous hemorrhage and the lesion reaches the surface of brainstem. These procedures should be performed by experienced neurosurgeons in referral centers employing all the currently available technology.
Following the collapse of the Soviet Union, an energy crisis in Tajikistan led to extensive deforestation. Initial financial investment is necessary for the reforestation of the severely degraded ...areas. In such areas, the State Forest Agency, with the support of the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH on behalf of the Federal Ministry for Economic Cooperation and Development (BMZ), began to test the Saving Book Approach (SBA) in Gorno Badakhshan region. SBA is a specific scheme of Payments for Ecosystem Services reforestation scheme. Local people participating in SBA receive compensation for six years, if the workload is fulfilled. This research has been carried out in order to analyze people's willingness to enroll in SBA and the suitability of certain forest plots for SBA implementation. The empirical results show that out of the factors tested — ‘benefit expectations’, ‘social pressure’, ‘age’, ‘income’ and ‘ability’, ‘ability’ was the only influential factor for willingness to enroll. ‘Ability’ is defined as the labor force availability, physical ability and amount of available time of the labor force in the household. The suitability of the forest plot depends on the needed investments for reforestation activities. Indeed, the willingness to enroll in SBA of local people does not necessarily match with plot suitability. These findings contribute to the improvement of the determination and understanding of factors that influence local peoples' decision to enroll and thus, provide the international development community with useful information for the design of future payment schemes.
► Key factors of peoples' willingness to enroll in reforestation scheme were analyzed. ► The rehabilitation costs of the forest plots are estimated. ► ‘Ability’ is the only significant factor influencing people’s decision. ► Out of three study sites only one is suitable for reforestation.
The ‘totality-of-the-evidence’ biosimilarity concept requires that sufficient structural, functional, nonclinical, and clinical data are acquired in a stepwise manner, to demonstrate that no ...clinically meaningful differences in quality, safety, or efficacy are observed compared with the reference product. We describe the totality of the evidence for PF-06438179/GP1111 (PF-SZ-IFX; IXIFI™ infliximab-qbtx/Zessly®) that supported its approval as an infliximab (IFX) biosimilar for all eligible indications of reference IFX (ref-IFX; Remicade®) in Europe and in the US. Analytical similarity involving in vitro assays capable of distinguishing structural or functional differences between PF-SZ-IFX and ref-IFX formed a foundation for the biosimilarity exercise. Differences identified in N-glycosylation and charge heterogeneity were found not to impact the results in in vitro biological assays reflective of the pharmacology underlying the mechanisms of action (tumor necrosis factor binding, reverse signaling, antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity) of IFX across disease indications. Similarity was assessed in a comparative clinical pharmacokinetic study and in a clinical efficacy and safety study in patients with rheumatoid arthritis, where therapeutic equivalence between PF-SZ-IFX and ref-IFX provided confirmatory evidence of biosimilarity, and, when coupled with the analytical similarity already established, supported extrapolation to all eligible disease indications of ref-IFX.
Annexin A6 is a calcium-dependent membrane-binding protein that interacts with signalling proteins, including the GTPase-activating protein p120GAP, one of the most important inactivators of Ras. ...Since we have demonstrated that annexin A6 inhibits EGF- and TPA-induced Ras signalling, we investigated whether modulation of Ras activity by annexin A6 was mediated via altered subcellular localization of p120GAP. First, we exploited our observation that high-density lipoproteins (HDL) can activate the Ras/MAP kinase pathway. Expression of annexin A6 caused a significant reduction in HDL-induced activation of Ras and Raf-1. Annexin A6 promoted membrane binding of p120GAP in vitro, and plasma membrane targeting of p120GAP in living cells, both in a Ca(2+)-dependent manner, which is consistent with annexin A6 promoting the Ca(2+)-dependent assembly of p120GAP-Ras at the plasma membrane. We then extended these studies to other cell types and stimuli. Expression of annexin A6 in A431 cells reduced, while RNAi-mediated suppression of annexin A6 in HeLa cells enhanced EGF-induced Ras and Erk activation. Importantly, the enhancement of Ras activation following RNAi-mediated reduction in p120GAP levels was more marked in annexin A6-expressing A431 cells than controls, indicating that the effect of annexin A6 on Ras was mediated via p120GAP. Finally, we demonstrated that annexin A6 promotes plasma membrane targeting of p120GAP in A431 cells in response to a variety of stimuli, resulting in colocalization with H-Ras. These findings demonstrate an important role for annexin A6 in regulating plasma membrane localization of p120GAP and hence Ras activity.
PDF
