Development of a Decafluorobiphenyl Cyclized Peptide Targeting the NEMO-IKKα/ß Interaction that Enhances Cell Penetration and Attenuates Lipopolysaccharide-Induced Acute Lung Injury.

Aberrant canonical NF-κB signaling has been implicated in diseases, such as autoimmune disorders and cancer. Direct disruption of the interaction of NEMO and IKKα/ß has been developed as a novel way to inhibit the overactivation of NF-κB. Peptides are a potential solution for disrupting protein-protein interactions (PPIs); however, they typically suffer from poor stability in vivo and limited tissue penetration permeability, hampering their widespread use as new chemical biology tools and potential therapeutics. In this work, decafluorobiphenyl-cysteine SNAr chemistry, molecular modeling, and biological validation allowed the development of peptide PPI inhibitors. The resulting cyclic peptide specifically inhibited canonical NF-κB signaling in vitro and in vivo, and presented positive metabolic stability, anti-inflammatory effects, and low cytotoxicity. Importantly, our results also revealed that cyclic peptides had huge potential in acute lung injury (ALI) treatment, and confirmed the role of the decafluorobiphenyl-based cyclization strategy in enhancing the biological activity of peptide NEMO-IKKα/ß inhibitors. Moreover, it provided a promising method for the development of peptide-PPI inhibitors.

Orally administered MOTS-c analogue ameliorates dextran sulfate sodium-induced colitis by inhibiting inflammation and apoptosis.

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gastrointestinal tract (GI). Currently, the treatment options for IBD are limited. It has been reported that a novel bioactive mitochondrial-derived peptide (MOTS-c) encoded in the mitochondrial 12S rRNA, suppresses inflammatory response by enhancing the phagocytosis of macrophages. The aim of this study was to investigate the protective effects of MOTS-c against dextran sulfate sodium (DSS)-induced colitis. The results showed that intraperitoneal (i.p.) administration of MOTS-c significantly ameliorated the symptoms of DSS-induced experimental colitis, such as body weight loss, colon length shortening, diarrhea, and histological damage. MOTS-c down-regulated the expression of pro-inflammatory cytokines, decreased the plasma levels of myeloperoxidase, and inhibited the activation of macrophages and recruitment of neutrophils. Moreover, treatment with MOTS-c exhibited anti-apoptotic effects and significantly suppressed the phosphorylation of AMPKα1/2, ERK, and JNK. Notably, oral administration of MOTS-c did not result in any significant improvements. Screening of cell penetrating peptides was performed, (PRR)5 was linked to the C-terminus of MOTS-c through a linker to synthesize a new molecule (termed MP) with better penetration into the colon epithelium. In vitro experiments revealed the longer half-life of MP than MOTS-c, and in vivo experiments showed that oral administration of MP significantly ameliorated DSS-induced colitis. CONCLUSION: The present results demonstrate a protective role of MOTS-c in experimental IBD.

Peripheral Administration of a Cell-Penetrating MOTS-c Analogue Enhances Memory and Attenuates Aß1-42- or LPS-Induced Memory Impairment through Inhibiting Neuroinflammation.

MOTS-c is a 16-amino acid mitochondrial derivative peptide reported to be involved in regulating insulin and metabolic homeostasis via the AMP activated protein kinase (AMPK). AMPK agonist AICAR has been reported to improve cognition. Previous reports also pointed out that MOTS-c may be effective as a therapeutic option toward the prevention of the aging processes. Therefore, we investigated the roles of MOTS-c in the memory recognition process. The results showed that central MOTS-c not only enhanced object and location recognition memory formation and consolidation but also ameliorated the memory deficit induced by Aß1-42 or LPS. The memory-ameliorating effects of MOTS-c could be blocked by AMPK inhibitor dorsomorphin. Moreover, MOTS-c treatment significantly increased the phosphorylation of AMPK but not ERK, JNK, and p38 in the hippocampus. The underlying mechanism of MOTS-c neuroprotection may involve inhibiting the activation of astrocytes and microglia and production of proinflammatory cytokines. In addition, we found that peripheral administration of MOTS-c does not cross the blood-brain barrier (BBB) and plays an effect. In order to improve the brain intake of MOTS-c, we screen out (PRR)5, a cell penetrating peptides, as a carrier for MOTS-c into the brain. Then in the NOR task, intranasal or intravenous MP (cell-penetrating MOTS-c analogue) showed good memory performance on memory formation, memory consolidation, and memory impairment. Near-infrared fluorescent experiments showed the real-time biodistribution in brain after intranasal or intravenous infusion of MP. These results suggested that MOTS-c might be a new potential target for treatment of cognitive decline in AD.

Intranasal MMI-0100 Attenuates Aß1-42- and LPS-Induced Neuroinflammation and Memory Impairments via the MK2 Signaling Pathway.

Background: Accumulating evidence suggests inhibiting neuroinflammation as a potential target in therapeutic or preventive strategies for Alzheimer's disease (AD). MAPK-activated protein kinase II (MK2), downstream kinase of p38 mitogen activated protein kinase (MAPK) p38 MAPK, was unveiled as a promising option for the treatment of AD. Increasing evidence points at MK2 as involved in neuroinflammatory responses. MMI-0100, a cell-penetrating peptide inhibitor of MK2, exhibits anti-inflammatory effects and is in current clinical trials for the treatment of pulmonary fibrosis. Therefore, it is important to understand the actions of MMI-0100 in neuroinflammation. Methods: The mouse memory function was evaluated using novel object recognition (NOR) and object location recognition (OLR) tasks. Brain hippocampus tissue samples were analyzed by quantitative PCR, Western blotting, and immunostaining. Near-infrared fluorescent and confocal microscopy experiments were used to detect the brain uptake and distribution after intranasal MMI-0100 application. Results: Central MMI-0100 was able to ameliorate the memory deficit induced by Aß1-42 or LPS in novel object and location memory tasks. MMI-0100 suppressed LPS-induced activation of astrocytes and microglia, and dramatically decreased a series of pro-inflammatory cytokines such as TNF-α, IL-6, IL-1ß, COX-2, and iNOS via inhibiting phosphorylation of MK2, but not ERK, JNK, and p38 in vivo and in vitro. Importantly, one of the reasons for the failure of macromolecular protein or peptide drugs in the treatment of AD is that they cannot cross the blood-brain barrier. Our data showed that intranasal administration of MMI-0100 significantly ameliorates the memory deficit induced by Aß1-42 or LPS. Near-infrared fluorescent and confocal microscopy experiment results showed that a strong fluorescent signal, coming from mouse brains, was observed at 2 h after nasal applications of Cy7.5-MMI-0100. However, brains from control mice treated with saline or Cy7.5 alone displayed no significant signal. Conclusions: MMI-0100 attenuates Aß1-42- and LPS-induced neuroinflammation and memory impairments via the MK2 signaling pathway. Meanwhile, these data suggest that the MMI-0100/MK2 system may provide a new potential target for treatment of AD.