Complete Genome Sequence of a Klebsiella pneumoniae Strain Carrying Novel Variant blaKPC-203, Cross-Resistant to Ceftazidime/Avibactam and Cefiderocol, but Susceptible to Carbapenems, Isolated in Italy, 2023

Background: Klebsiella pneumoniae is a concerning pathogen, responsible for hospital-associated outbreaks. Multi drug resistant (MDR) strains are especially hard to treat. We conducted whole-genome sequencing on a MDR K. pneumoniae strain in order to identify genomic features potentially linked to its phenotype. Methods: DNA sequencing was performed on the Illumina iSeq 100 platform. Genome assembly was carried out with SPAdes. The genome was annotated with RASTtk. Typing was performed with MLST and Kaptive. Antibiotic resistance genes were detected with AMRFinderPlus and Abricate, and further verified with BLAST. Results: The strain exhibited resistance to ceftazidime/avibactam and cefiderocol, but remained susceptible to carbapenems. The strain belonged to sequence type ST101, serotype O1:K17. The analysis of antibiotic resistance genes indicated that the strain carried a novel KPC variant, designated as KPC-203, featuring a EL deletion at amino acid position 166-167, within the Omega-loop, and a nine-amino-acid insertion (LAVYTRAPM) at position 259. Sequence alterations were found in porin genes ompK35 and ompK36. Unlike molecular testing, which was able to detect the KPC-203 variant, all phenotypic carbapenemase detection methods achieved negative results. Conclusions: KPC-203, a novel KPC variant, showed a sequence modification in a cephalosporin resistance-associated hotspot. Interestingly, such alterations typically correlate with the restoration of carbapenem susceptibility. We hypothesize that KPC-203 likely led to resistance to ceftazidime/avibactam and cefiderocol, while maintaining susceptibility to carbapenems

Antigene MYCN Silencing by BGA002 Inhibits SCLC Progression Blocking mTOR Pathway and Overcomes Multidrug Resistance

: Small-cell lung cancer (SCLC) is the most aggressive lung cancer type, and is associated with smoking, low survival rate due to high vascularization, metastasis and drug resistance. Alterations in MYC family members are biomarkers of poor prognosis for a large number of SCLC. In particular, MYCN alterations define SCLC cases with immunotherapy failure. MYCN has a highly restricted pattern of expression in normal cells and is an ideal target for cancer therapy but is undruggable by traditional approaches. We propose an innovative approach to MYCN inhibition by an MYCN-specific antigene-PNA oligonucleotide (BGA002)-as a new precision medicine for MYCN-related SCLC. We found that BGA002 profoundly and specifically inhibited MYCN expression in SCLC cells, leading to cell-growth inhibition and apoptosis, while also overcoming multidrug resistance. These effects are driven by mTOR pathway block in concomitance with autophagy reactivation, thus avoiding the side effects of targeting mTOR in healthy cells. Moreover, we identified an MYCN-related SCLC gene signature comprehending CNTFR, DLX5 and TNFAIP3, that was reverted by BGA002. Finally, systemic treatment with BGA002 significantly increased survival in MYCN-amplified SCLC mouse models, including in a multidrug-resistant model in which tumor vascularization was also eliminated. These findings warrant the clinical testing of BGA002 in MYCN-related SCLC

A novel MYCN-specific antigene oligonucleotide deregulates mitochondria and inhibits tumor growth in MYCN-amplified neuroblastoma

Approximately half of high-risk neuroblastoma is characterized by MYCN amplification. N-Myc promotes tumor progression by inducing cell growth and inhibiting differentiation. MYCN has also been shown to play an active role in mitochondrial metabolism, but this relationship is not well understood. Although N-Myc is a known driver of the disease, it remains a target for which no therapeutic drug exists. Here, we evaluated a novel MYCN-specific antigene PNA oligonucleotide (BGA002) in MYCN-amplified (MNA) or MYCN-expressing neuroblastoma and investigated the mechanism of its antitumor activity. MYCN mRNA and cell viability were reduced in a broad set of neuroblastoma cell lines following BGA002 treatment. Furthermore, BGA002 decreased N-Myc protein levels and apoptosis in MNA neuroblastoma. Analysis of gene expression data from patients with neuroblastoma revealed that MYCN was associated with increased reactive oxygen species (ROS), downregulated mitophagy, and poor prognosis. Inhibition of MYCN caused profound mitochondrial damage in MNA neuroblastoma cells through downregulation of the mitochondrial molecular chaperone TRAP1, which subsequently increased ROS. Correspondingly, inhibition of MYCN reactivated mitophagy. Systemic administration of BGA002 downregulated N-Myc and TRAP1, with a concomitant decrease in MNA neuroblastoma xenograft tumor weight. In conclusion, this study highlights the role of N-Myc in blocking mitophagy in neuroblastoma and in conferring protection to ROS in mitochondria through upregulation of TRAP1. BGA002 is a potently improved MYCN-specific antigene oligonucleotide that reverts N-Myc\u2013dysregulated mitochondrial pathways, leading to loss of the protective effect of N-Myc against mitochondrial ROS. Significance: A second generation antigene peptide oligonucleotide targeting MYCN induces mitochondrial damage and inhibits growth of MYCN-amplified neuroblastoma cells

The MYCN inhibitor BGA002 restores the retinoic acid response leading to differentiation or apoptosis by the mTOR block in MYCN-amplified neuroblastoma

Background: Neuroblastoma is a deadly childhood cancer, and MYCN-amplified neuroblastoma (MNA-NB) patients have the worst prognoses and are therapy-resistant. While retinoic acid (RA) is beneficial for some neuroblastoma patients, the cause of RA resistance is unknown. Thus, there remains a need for new therapies to treat neuroblastoma. Here we explored the possibility of combining a MYCN-specific antigene oligonucleotide BGA002 and RA as therapeutic approach to restore sensitivity to RA in NB. Methods: By molecular and cellular biology techniques, we assessed the combined effect of the two compounds in NB cell lines and in a xenograft mouse model MNA-NB. Results: We found that MYCN-specific inhibition by BGA002 in combination with RA (BGA002-RA) act synergistically and overcame resistance in NB cell lines. BGA002-RA also reactivated neuron differentiation (or led to apoptosis) and inhibited invasiveness capacity in MNA-NB. Moreover, we found that neuroblastoma had the highest level of mRNA expression of mTOR pathway genes, and that BGA002 led to mTOR pathway inhibition followed by autophagy reactivation in MNA-NB cells, which was strengthened by BGA002-RA. BGA002-RA in vivo treatment also eliminated tumor vascularization in a MNA-NB mouse model and significantly increased survival. Conclusion: Taken together, MYCN modulation mediates the therapeutic efficacy of RA and the development of RA resistance in MNA-NB. Furthermore, by targeting MYCN, a cancer-specific mTOR pathway inhibition occurs only in MNA-NB, thus avoiding the side effects of targeting mTOR in normal cells. These findings warrant clinical testing of BGA002-RA as a strategy for overcoming RA resistance in MNA-NB

Protease-activated receptor 2 sensitizes the capsaicin receptor transient receptor potential vanilloid receptor 1 to induce hyperalgesia

Inflammatory proteases (mast cell tryptase and trypsins) cleave protease-activated receptor 2 (PAR2) on spinal afferent neurons and cause persistent inflammation and hyperalgesia by unknown mechanisms. We determined whether transient receptor potential vanilloid receptor 1 (TRPV1), a cation channel activated by capsaicin, protons, and noxious heat, mediates PAR2-induced hyperalgesia. PAR2 was coexpressed with TRPV1 in small- to medium-diameter neurons of the dorsal root ganglia (DRG), as determined by immunofluorescence. PAR2 agonists increased intracellular [Ca2+] ([Ca2+]i) in these neurons in culture, and PAR2-responsive neurons also responded to the TRPV1 agonist capsaicin, confirming coexpression of PAR2 and TRPV1. PAR2 agonists potentiated capsaicin-induced increases in [Ca2+]i in TRPV1-transfected human embryonic kidney (HEK) cells and DRG neurons and potentiated capsaicin-induced currents in DRG neurons. Inhibitors of phospholipase C and protein kinase C (PKC) suppressed PAR2-induced sensitization of TRPV1-mediated changes in [Ca2+]i and TRPV1 currents. Activation of PAR2 or PKC induced phosphorylation of TRPV1 in HEK cells, suggesting a direct regulation of the channel. Intraplantar injection of a PAR2 agonist caused persistent thermal hyperalgesia that was prevented by antagonism or deletion of TRPV1. Coinjection of nonhyperalgesic doses of PAR2 agonist and capsaicin induced hyperalgesia that was inhibited by deletion of TRPV1 or antagonism of PKC. PAR2 activation also potentiated capsaicin-induced release of substance P and calcitonin gene-related peptide from superfused segments of the dorsal horn of the spinal cord, where they mediate hyperalgesia. We have identified a novel mechanism by which proteases that activate PAR2 sensitize TRPV1 through PKC. Antagonism of PAR2, TRPV1, or PKC may abrogate protease-induced thermal hyperalgesia

Complete genome sequence and antimicrobial resistance analysis of ESBL-producing Shigella sonnei carrying small cryptic plasmids isolated in northern Italy.

Objectives: Herein, we sequenced and assembled the genome of a Shigella sonnei isolate carrying several small plasmids using a hybrid approach that combined Oxford Nanopore Technologies and Illumina platforms. Methods: Whole-genome sequencing was conducted using the Illumina iSeq 100 and Oxford Nanopore MinION systems, and the resulting reads were used for hybrid genome assembly via Unicycler. Coding sequences were annotated using RASTtk, while genes involved in antimicrobial resistance and virulence were identified using AMRFinderPlus. Plasmid nucleotide sequences were aligned to the NCBI non-redundant database using BLAST, and replicons were identified using PlasmidFinder. Results: The genome consisted of 1 chromosome (4 801 657 bp), 3 major plasmids (212 849 bp, 86 884 bp, and 83 425 bp, respectively) and 12 small cryptic plasmids (ranging from 8390 bp to 1822 bp). BLAST analysis revealed that all plasmids were highly similar to previously deposited sequences. Genome annotation predicted 5522 coding regions, including 19 antimicrobial resistance genes and 17 virulence genes. Four of the antimicrobial resistance genes were located in small plasmids, and four of the virulence genes were located in a large virulence plasmid. Conclusion: The presence of antimicrobial resistance genes in small cryptic plasmids may represent an overlooked mechanism for the propagation of these genes among bacterial populations. Our work provides new data on these elements that may inform the development of new strategies to control the spread of extended spectrum β-lactamase-producing bacterial strains

Clonal dissemination of Klebsiella pneumoniae resistant to cefiderocol, ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam co-producing KPC and OXA-181 carbapenemase

Objectives: Herein, we describe the epidemiology of carbapenemase-producing Enterobacterales (CPE) before and during the COVID-19 pandemic. Also, we report the emergence of an outbreak of Klebsiella pneumoniae strains co-producing KPC and OXA-181 carbapenemase, resistant to novel β-lactam/β-lactamase inhibitors (βL-βLICs) and cefiderocol. Methods: CPE were collected during a period of 3 years from 2019 to 2021. Antimicrobial susceptibility testing for novel βL-βLICs and cefiderocol was performed by MIC test strips and microdilution with iron-depleted broth. WGS was performed on 10 selected isolates using the Illumina platform, and resistome analysis was carried out by a web-based pipeline. Results: Between January 2019 and December 2021, we collected 1430 carbapenemase producers from 957 patients with infections due to CPE. KPC was the most common carbapenemase, followed by VIM, OXA-48 and NDM. During 2021, we identified 78 K. pneumoniae co-producing KPC and OXA-181 carbapenemases in 60 patients, resistant to meropenem/vaborbactam and imipenem/relebactam. Resistance to ceftazidime/avibactam and cefiderocol was observed respectively in 7 and 8 out of the 10 sequenced K. pneumoniae. Genome analysis showed that all isolates were clonally related, shared a common porin and plasmid content, and carried blaOXA-181 and blaKPC carbapenemases. Specifically, 4 out of 10 isolates carried blaKPC-3, while 6 harboured mutated blaKPC. Of note, KPC producers resistant to ceftazidime/avibactam and harbouring mutated blaKPC exhibited higher MICs of cefiderocol (median MIC 16 mg/L, IQR 16-16) than strains harbouring WT blaKPC-3 (cefiderocol 9 mg/L, IQR 1.5-16). Conclusions: Our results highlight the need for continuous monitoring of CPE to limit widespread MDR pathogens carrying multiple mechanisms conferring resistance to novel antimicrobial molecule

Kinin B-1 and B-2 receptors in pig vessels: characterization of two monoreceptor systems

The coronary artery and renal vein of the adult pig are sensitive and reliable monoreceptor systems for studying kinin receptors. The pig coronary artery with intact endothelium is highly sensitive to bradykinin (BK, pEC50 8.6), while being insensitive to the B1 receptor agonist, LysdesArg9BK. The tissue responds to BK with concentration-dependent relaxation, which is prevented by B2 receptor antagonists, particularly DArg[Hyp3, Thi5, DTic7, Oic8]BK (HOE 140, pKB 9.3), (E)-3-(6-acetoamido-3-pyridyl)-N-(N-{2, 4-dichloro-3-[(2-methyl-8-quinolinyl)oxy-methyl]phenyl}-N- methylaminocarbonyl-methyl)acrylamide (FR 173657), a new non peptide compound (pKB 9.3), while B1 receptor antagonists (e.g. Lys[Leu8]desArg9BK) are inactive. The order of potency of kinin-related peptides in this vessel is: LysBK > or = BK > [Hyp3]BK > [Aib7]BK, a sequence typical of a B2 receptor system. Antagonists such as HOE 140 and FR 173657, at high concentrations reduce the maximum effect of BK and thus behave as noncompetitive antagonists. The kinin B1 receptor was studied in the pig renal vein without endothelium and incubated for several hours in order to allow for the de novo formation of this functional site. After 7-8 h in vitro incubation, the vessel shows high sensitivity to LysdesArg9BK (pEC50 8.3) and is insensitive to BK. The pig renal vein responds to B1 receptor agonists with concentration-dependent contraction which maintains a stable plateau and is prevented by selective B1 receptor antagonists such as Lys[Leu8]desArg9BK (pKB 6.7). The most active antagonist has been found to be desArg9HOE 140 (pA2 7.6) which acts as competitive antagonist in this preparation. Some B2 antagonists (e.g. HOE 140) show weak (pKB 6.1) anti-B1 receptor activity while the non-peptide compound FR 173657 is inactive on the B1 receptor and therefore acts as a potent and selective kinin B2 receptor antagonist in the pig. The data obtained in this study allow us to compare the porcine B2 and B1 receptors with those of other species including man, and underline some interesting features that are unique to the porcine functional sites