There is a growing interest in the complex role of host defense peptides (HDPs) in the pathophysiology of several immune-mediated inflammatory diseases. The physicochemical properties and selective interaction of HDPs with various receptors define their immunomodulatory effects. However, it is quite challenging to understand their function because some HDPs play opposing pro-inflammatory and anti-inflammatory roles, depending on their expression level within the site of inflammation. While it is known that HDPs maintain constitutive host protection against invading microorganisms, the inducible nature of HDPs in various cells and tissues is an important aspect of the molecular events of inflammation. This review outlines the biological functions and emerging roles of HDPs in different inflammatory conditions. We further discuss the current data on the clinical relevance of impaired HDPs expression in inflammation and selected diseases.

Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet.

Campylobacter jejuni is the leading cause of bacterial gastroenteritis (campylobacteriosis) in humans worldwide, and the most frequent pathogen associated with Guillain-Barré syndrome (GBS) and Miller-Fisher syndrome (MFS). The study was designed in order to assess similarities between genomes of Campylobacter jejuni strains, isolated from children suffering from acute diarrhea in northeastern Poland, in comparison to C. jejuni genomes stored in public databases. The analysis involved phylogeny, resistome and virulome. In addition, the Campylobacter PubMLST database was used to estimate the prevalence of the analyzed C. jejuni sequence type (STs) in other countries. Campylobacter jejuni ST50, ST257 and ST51 represented 5.3%, 4.5% and 2.2% of the PubMLST records, respectively. Overall, strains representing the STs showed common resistance to tetracyclines (51.3%) and fluoroquinolones (31.8%), mediated through the tetO gene (98.2%) and point mutation (T86I) in the gyrA gene (100%). However, the latter was present in all our isolates. The major differences in virulence patterns concerned serotypes, lipooligosaccharide (LOS) classes and certain clinically relevant genes. Campylobacter jejuni ST50, ST51 and ST257 are among the top ten of STs isolated in Europe. WGS revealed diversity of serotypes and LOS classes in ST50 strains, that deserves further clinical and epidemiological investigations as it might be related to a risk of post-infectious neurological sequels such as Guillain-Barré syndrome. Additionally, the results implicate lower pathogenic potential and distinct transmission chains or reservoirs for C. jejuni ST51 isolates responsible for campylobacteriosis in northeastern Poland.

Plasma gelsolin (pGSN) is a highly conserved abundant circulating protein, characterized by diverse immunomodulatory activities including macrophage activation and the ability to neutralize pro-inflammatory molecules produced by the host and pathogen. Using a murine model of Gram-negative sepsis initiated by the peritoneal instillation of Pseudomonas aeruginosa Xen 5, we observed a decrease in the tissue uptake of IRDye^®800CW 2-deoxyglucose, an indicator of inflammation, and a decrease in bacterial growth from ascitic fluid in mice treated with intravenous recombinant human plasma gelsolin (pGSN) compared to the control vehicle. Pretreatment of the murine macrophage line RAW264.7 with pGSN, followed by addition of Pseudomonas aeruginosa Xen 5, resulted in a dose-dependent increase in the proportion of macrophages with internalized bacteria. This increased uptake was less pronounced when cells were pretreated with pGSN and then centrifuged to remove unbound pGSN before addition of bacteria to macrophages. These observations suggest that recombinant plasma gelsolin can modulate the inflammatory response while at the same time augmenting host antibacterial activity.

In 2023, a significant increase in Streptococcus pyogenes, Group A Streptococcus (GAS) culture positivity was observed in Czech microbiological laboratories. We conducted a multicentre study to obtain epidemiological data and characterise circulating strains. Eleven microbiology departments provided data on single-patient GAS-positive cultures from 2017 to 2023. Additionally, 10 consecutive, single-patient GAS isolates from 12 hospitals were submitted in May 2023 for whole-genome sequencing and antimicrobial susceptibility testing. In 2023, there was a significant increase in GAS-positive cultures compared to the periods of 2017-2019 (p = 0.002), 2020-2021 (p < 0.00001), and 2022 (p = 0.001), with a disproportionate increase in children. Among 120 isolates, 12 different emm types and 16 multi-locus sequence types (STs) were identified, with emm1 (ST28, 35.0 %) and emm12 (STs 36, 101, 242, 1366, 32.5 %) being the most prevalent. Clonal clustering of emm1 and emm12 isolates across different study sites and geographic regions was demonstrated by whole-genome MLST analysis. When searching for shared virulence genes exclusive to emm1 and emm12 but absent in other emm types, immune evasion and colonisation factors (the streptococcal inhibitor of complement-sic gene in emm1, the distantly related sic-drs gene in emm12, and the sda1 gene in both) were identified. An upsurge in GAS infections, predominantly caused by emm1 and emm12, was identified in the Czech Republic. The combination of shared virulence factors, altered herd immunity and naïve immunity in children, resulting from contact precautions measures during the COVID-19 pandemic, may have contributed to their increased spread.

Small non-coding RNAs have been recognized as potential controllers of various biological functions, including gene expression, molecular growth, and physiological functions. The diverse ways considerably aid the prognosis and diagnosis of many diseases which microRNAs (miRNAs) manifest themselves. It is crucial to successfully isolate miRNAs from various tissues and bodily fluids since they have a wide range of uses as clinical biomarkers for the precise detection of many diseases, cancer risk assessment, and investigation of different metabolic processes and gene activity. The present study compares the available RNA extraction protocols and renders an improvised protocol for isolating RNA and subsequent extraction of miRNA molecules. Different RNA isolation protocols were analyzed: Direct-zol™ RNA MiniPrep Plus kit, TRIzol^TM reagent, and non-kit organic RNA extraction methods. The quality of RNA was assessed using spectrophotometry and bleach gel electrophoresis. Here, we have measured the expression of miRNA10b, a specific biomarker candidate for the prognosis of colorectal cancer that plays a major role in metastasis. The amplified expression of miRNA was demonstrated using Real-time PCR. The qualitative and quantitative analysis of the extracted RNA was evaluated. The modified extraction protocol was found to yield good-qualitymiRN. The modified RNA extraction protocol is a simple, cost-effective, efficient method for miRNA isolation from cell lines.