There is increased concern that the quality, generalizability, and reproducibility of biomedical research can be influenced by the sex of animals used. We studied the differences between male and female mice in response to invasive pulmonary mucormycosis including susceptibility to infection, host immune reaction, and responses to antifungal therapy. We used diabetic ketoacidotic (DKA) or neutropenic mice infected with either Rhizopus delemar or Mucor circinelloides. The only difference detected was that when DKA mice were infected with M. circinelloides, female mice were more resistant to infection than male mice (median survival time of 5 vs. 2 days for female and male mice, respectively). However, a 100% lethality was detected among infected animals of both sexes. Treatment with either liposomal amphotericin B (L-AMB) or posaconazole (POSA) protected mice from infection and eliminated the difference seen between infected but untreated female and male mice. Treatment with L-AMB consistently outperformed POSA in prolonging survival and reducing tissue fungal burden of DKA and neutropenic mice infected with R. delemar or M. circinelloides, in both mouse sexes. Although little difference was detected in cytokine levels among both sexes, mucormycosis infection in the DKA mouse model induced more inflammatory cytokines/chemokines involved in neutrophil (CXCL1) and macrophage (CXCL2) recruitment vs. uninfected mice. As expected, this inflammatory response was reduced in the neutropenic mouse model. Our studies show that there are few differences between female and male DKA or neutropenic mice infected with mucormycosis with no effect on the outcome of treatment or host immune response.

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen and is the leading cause of infection in patients with cystic fibrosis (CF). The ability of P. aeruginosa to evade host responses and develop into chronic infection causes significant morbidity and mortality. Several mouse models have been developed to study chronic respiratory infections induced by P. aeruginosa, with the bead agar model being the most widely used. However, this model has several limitations, including the requirement for surgical procedures and high mortality rates. Herein, we describe novel and adapted biologically relevant models of chronic lung infection caused by P. aeruginosa. Three methods are described, a clinical isolate infection model, utilizing isolates obtained from patients with CF, an incomplete antibiotic clearance model, leading to bacterial bounce-back and the establishment of chronic infection, and an adapted water bottle chronic infection model. These models circumvent the requirement for surgical procedure and importantly, can be induced with clinical isolates of P. aeruginosa and in wild-type mice. We also demonstrate successful induction of chronic infection in the transgenic βENaC murine model of CF. We envisage that the models described will facilitate the investigations of host and microbial factors, and the efficacy of novel antimicrobials, during chronic P. aeruginosa respiratory infections.

A form of dementia distinct from healthy cognitive aging, Alzheimer's disease (AD) is a complex multi-stage disease that currently afflicts over 50 million people worldwide. Unfortunately, previous therapeutic strategies developed from murine models emulating different aspects of AD pathogenesis have failed. Consequently, researchers are now developing models that express several aspects of pathogenesis that better reflect the clinical situation in humans. As such, this review seeks to provide insight regarding current applications of mammalian models in AD research by addressing recent developments and characterizations of prominent transgenic models and their contributions to pathogenesis as well as discuss the advantages, limitations, and application of emerging models (hAβ-KI) that better capture genetic heterogeneity and mixed pathologies observed in the clinical situation.

Gaucher disease (GD) is a lysosomal storage disorder stemming from biallelic mutations in GBA1, characterized by glucocerebrosidase dysfunction and glucocerebroside and glucosylsphingosine accumulation. Since phenotypes of murine models of GD often differ from those in patients, careful characterization of Gba1 mutant mice is necessary to establish their ability to model GD. We performed side-by-side comparative biochemical and pathologic analyses of four murine Gba1 models with genotypes L444P/L444P (p.L483P/p.L483P), L444P/null, D409H/D409H (p.D448H/p.D448H), and D409H/null, along with matched wildtype mice, all with the same genetic background and cage conditions. All mutant mice exhibited significantly lower glucocerebrosidase activity (p < 0.0001) and higher glucosylsphingosine levels than wildtype, with the lowest glucocerebrosidase and highest glucosylsphingosine levels in mice carrying a null allele. Although glucocerebrosidase activity in L444P and D409H mice was similar, D409H mice showed more lipid accumulation. No Gaucher or storage-like cells were detected in any of the Gba1 mutant mice. Quantification of neuroinflammation, dopaminergic neuronal loss, alpha-synuclein levels and motor behavior revealed no significant findings, even in aged animals. Thus, while the models may have utility for testing the effect of different therapies on enzymatic activity, they did not recapitulate the pathological phenotype of patients with GD, and better models are needed.

Porcine recombinant NK-lysin (prNK-lysin) has been shown to inhibit the proliferation and metastasis of hepatocellular carcinoma (HCC) cells in vitro. However, its effects on the proliferation and metastasis of HCC cells in vivo remain unclear. In this study, allograft murine model using the murine HCC cell line Hepa1-6 was employed to investigate the anticancer effects of prNK-lysin. Initially, the in vitro anticancer efficacy of prNK-lysin was evaluated on Hepa1-6 cells, demonstrating that prNK-lysin effectively inhibited both proliferation and metastasis through the induction of oncosis. Subsequently, the in vivo anticancer efficacy of prNK-lysin was assessed using a mouse liver orthotopic implantation model and a lung metastasis model of Hepa1-6 cells in BALB/cA-nu mice. Administration of 13 mg/kg prNK-lysin could inhibited tumor growth in the liver and metastasis to the lungs. Our results demonstrate that prNK-lysin possesses strong anti-HCC effects both in vitro and in vivo, with the induction of oncosis as potential molecular mechanisms for its anticancer activity.

Antimicrobial peptides (AMPs) are regarded as a promising alternative to traditional antibiotics in the face of ever-increasing resistance. Our research has focused on crotalicidin (Ctn), an AMP from a snake venom, and a fragment thereof, Ctn[15-34], with improved in vitro antimicrobial and anticancer activities and remarkable serum stability. As the retroenantio versions of both AMPs maintained favorable profiles, in this work we evaluate the in vivo efficacy of both the na-tive-sequence AMPs and their retroenantio counterparts in a murine infection model with Aci-netobacter baumannii. A significant reduction in bacterial levels is found in the mice treated with Ctn[15-34]. However, contrary to expectations, the retroenantio analogues either exhibit toxicity or lack efficacy when administered to mice.

Background: Pteropodine (PT) is a component of some plants with potentially useful pharmaco-logical activities for humans. This compound has biomedical properties related to the modulation of the immune system, nervous system, and inflammatory processes. This study addresses the an-ti-inflammatory and antioxidant capacity of pteropodin in a murine model of arthritis and induced edema of the mouse ear. Methods: To evaluate the anti-inflammatory activity, we used the reversed passive Arthus reaction (RPAR), which includes the rat paw edema test, the rat pleurisy test, and a mouse ear edema model. The antioxidant effect was evaluated by determining the myeloperoxidase enzyme activity. Results: PT showed an anti-inflammatory effect in the different specific and non-specific tests. We found a 52 to 74% of inhibitory effect of PT in the rat paw edema test, 52% of reduction of the pleural exudate volume, and low neutrophil count (28%), when compared to the control group. We also found a 81% of inflammatory inhibition of the ear edema, and a significant myeloperoxidase enzyme inhibition by the three doses of PT. Conclusions: PT exerted a potent an-ti-inflammatory effect in the acute inflammation model in rodents.

The prevalence of congenital hearing impairment (HI) is highest in Africa. Estimates evaluated genetic causes to account for 31% of HI cases in Africa, but the identification of associated causative genes mutations have been challenging. In this study, we reviewed the potential roles, in humans, of 38 novel genes identified in a murine study. We gathered information from various genomic annotation databases and performed functional enrichment analysis using online resources i.e. genemania and g.proflier. Results revealed that 27/38 genes are express mostly in the brain, suggesting additional cognitive roles. Indeed, HERC1- R3250X had been associated with intellectual disability in a Moroccan family. A homozygous 216-bp deletion in KLC2 was found in two siblings of Egyptian descent with spastic paraplegia. Up to 27/38 murine genes have link to at least a disease, and the commonest mode of inheritance is autosomal recessive (n=8). Network analysis indicates that 20 other genes have intermediate and biological links to the novel genes, suggesting their possible roles in HI. This study will contribute to advance our knowledge in unravelling the biological roles of novel murine HI genes in humans and could enhance the understanding of the genetic causes of HI in Africans.

The COVID-19 pandemic, declared in early 2020, is an unprecedented global health crisis, causing over 7.0 million deaths and ongoing challenges. While the pharmaceutical industry expedited vaccine development, mutant SARS-CoV-2 strains remain a major fear. Moreover, concerns regarding the long-term health repercussions of COVID-19-affected individuals persist since individuals affected by mild and moderate to severe SARS-CoV-2 infection experience long-term cardiovascular complications, liver dysfunction, pulmonary afflictions, kidney impairments, and most importantly neurocognitive deficits. In recent studies, we documented pathophysiological changes in various organs following the post-acute infection of mice with murine hepatitis virus-1 (MHV-1), a coronavirus, at both 7 days and 12 months after infection. One part of the body that can be drastically affected by SARS-CoV-2 is the skin. Studies have shown major changes in the skin post-acute SARS CoV-2 infection in humans. However, long-term dermatologic changes post-COVID have never been explored. For the first time, we show several cutaneous findings both at the acute stages and long-term post-infection of mice with MHV-1 coronavirus (a promising experimental model to study acute and long-COVID). Precisely, we found destruction of the epidermal layer, an increase in the number of hair follicles, extensive collagen deposition in the dermal layer, and hyperplasticity of the sebaceous glands at the acute stages, along with thinning of the panniculus carnosus, as well as the adventitial layer, which corresponds well with studies in humans. In contrast, the cutaneous investigation in the long-COVID phase shows the absence of hair follicles from both the epidermal and dermal layers, the destruction of adipose tissues, and the devastation of the epidermal layer. Further, treatment of these mice with a 15 amino acid synthetic peptide, SPIKENET (SPK), which was effective in preventing Spike glycoprotein-1 binding with host receptors, as well as has a potent anti-inflammatory response to severe inflammatory stimulus) restored the loss of hair follicles and re-architected the epidermal and dermal layers. Additionally, destruction in fatty tissue in the infected mice was successfully restored post-treatment with SPK. These findings suggest that SARS-CoV-2 initiates the changes early post-infection, leading to devastating skin alterations in the long term which can be prevented by our newly identified peptide drug SPK.

In cancer patients, hyponatremia is detected in about 40% of cases at hospital admission and has been associated to a worse outcome. We have previously observed that cancer cells from differ-ent tissues show a significantly increased proliferation rate and invasion potential, when cul-tured in low extracellular [Na+]. We have recently developed an animal model of hyponatremia using Foxn1nu/nu mice. The aim of the present study was to compare tumor growth and inva-sivity of the neuroblastoma cell line SK-N-AS in hyponatremic vs. normonatremic mice. Ani-mals were subcutaneously implanted with luciferase-expressing SK-N-AS cells. When masses reached about 100 mm3, hyponatremia was induced in a subgroup of animals via desmopressin infusion. Tumor masses were significantly greater in hyponatremic mice, starting from day 14 and until the day of sacrifice (day 28). Immunohistochemical analysis showed a more intense vascularization and higher levels of expression of the proliferating cell nuclear antigen, chro-mogranin A and heme oxigenase-1 gene in hyponatremic mice. Finally, metalloproteases were also more abundantly expressed in hyponatremic animals compared to control ones. To our knowledge, this is the first in vivo demonstration that hyponatremia is associated to increased cancer growth by activating molecular mechanisms that promote proliferation, angiogenesis and invasivity.

Cells are influenced by several biomechanical aspects of their microenvironment, such as substrate geometry. According to the literature, substrate geometry influences the behavior of muscle cells; in particular, the curvature feature improves cell proliferation. However, the effect of the substrate geometry on the myogenic differentiation process is not clear and needs to be further investigated. Here, we show that the 3D co-printing technique allows the realization of substrates. To test the influence of the co-printing technique on cellular behavior we realized linear polycaprolactone substrates with channels in which a fibrinogen-based hydrogel loaded with C2C12 cells was deposited. Cell viability and differentiation were investigated up to 21 days in culture. The results suggest that this technology significantly improves the differentiation at 14 days. Therefore, we investigate the substrate geometry influence by comparing three different co-printed geometries – linear, circular, and hybrid structures (linear and circular features combined). Based on our results, all structures exhibit optimal cell viability (&gt; 94%) but the linear pattern allows to increase the in-vitro cell differentiation, in particular after 14 days of culture. This study proposes an endorsed approach for creating artificial muscles for future skeletal muscle tissue engineering applications.

Murine herpesvirus-68 (MHV-68) productively infects the mouse lungs, exhibiting a complex pathology characteristic of both acute viral infections and chronic respiratory diseases. We sought to discover proteins differentially expressed in bronchoalveolar lavage (BAL) from mice infected with MHV-68. Mice were infected intranasally with MHV-68. After 9 days, as the lytic phase of infection resolved, differential BAL proteins were identified by 2D electrophoresis and mass spectrometry. Of 23 unique proteins, acute phase proteins, vitamin A transport, and oxidative stress response factors Pdx6 and EC-SOD (Sod3) were enriched. Correspondingly, iNOS2 was induced in lung tissue by 7 days post infection. Oxidative stress was partly a direct result of MHV-68 infection, as reactive oxygen species (ROS) were induced in cultured murine NIH3T3 fibroblasts and human lung A549 cells infected with MHV-68. Finally, mice were infected with a recombinant MHV-68 co-expressing inflammatory cytokine murine interleukin 6 (IL6) showed exacerbated oxidative stress and soluble type I collagen characteristic of tissue recovery. Thus, oxidative stress appears to be a salient feature of MHV-68 pathogenesis, in part caused by lytic replication of virus and IL6. Proteins and small molecules in lung oxidative stress networks therefore may provide new therapeutic targets to ameliorate respiratory virus infections.

Phagosomal escape and intracellular survival, often accompanied by Small Colony Variants (SCVs) formation, are typical features of infections caused by S. aureus. The survival in macro-phages favours S. aureus dissemination and complicates treatment. RAW 264.7 murine macro-phages infected with S. aureus USA300 and treated with erythromycin and 20mM carnosine, alone and in combination, were used as experimental model. SCVs were isolated from all treat-ment conditions, but only those undergoing the pressure of combined erythromycin and carnosine for 48 hours were stable for at least six passages on blood agar. Nucleic acid extraction was car-ried out for S. aureus USA300 wild-type and stable SCVs. Whole Genome Sequencing (WGS) was performed using Illumina DNA Prep and Illumina MiSeq, and quantitative reverse transcription PCR was performed. WGS analysis did not yield mutations pointing to differences between S. au-reus USA300 and stable SCVs, therefore the focus was shifted to evaluating gene expression vari-ations. Genes such as zur, mntR, uhpt, fur, sdrE were shown to be significantly up-regulated in SCVs compared to S. aureus USA300 wild-type, suggesting a global change that allows adapta-tion to intracellular persistence, including protection from inflammatory response and evasion of the immune system.

Staphylococcus aureus (S. aureus) is a major human pathogen that requires new antibiotics with unique mechanism. A new pleuromutilin derivative, 14-O-[(4,6-Diaminopyrimidine-2-yl) thioacetyl] mutilin (DPTM), has been synthesized and proved as a potent antibacterial agent using in vitro and in vivo assays. In the present study, DPTM was further in vitro evaluated against Methicillin-resistant Staphylococcus aureus (MRSA) isolated from dairy farms and outperformed tiamulin fumarate, a pleuromutilin drug used for veterinary. Moreover, a murine skin wound model caused by MRSA infection was established and the healing effect of DPTM was investigated. The results showed that DPTM could promote the healing of MRSA skin infection, reduce the bacterial burden of infected skin MRSA and decrease the secretion of IL-6 and TNF-α inflammatory cytokines in plasma. These results provided the basis for further in-depth drug targeted studies of DPTM as a novel antibacterial agent.

The therapeutic management of melanoma, the most aggressive form of skin cancer, remains challenging. In the search for more effective therapeutic options, metal-based complexes are being investigated for their anticancer properties. Cisplatin was the first clinically approved plati-num-based drug and, based on its success, other metals (e.g. gold) are being used to design novel compounds. In the present work, the antimelanoma potential of a new organometallic cy-clometalated Au(III) complex [[Au(CNOxN)Cl2] (CNOxN = 2-(phenyl-(2-pyridinylmethylene)aminoxy acetic acid))] (ST004) was evaluated in vitro and in vivo. Furthermore, this new gold-based complex was associated to liposomes with the lipid composition DMPC:DOPE:DSPE-PEG (50:45:5) to overcome solubility and stability problems, as well as to promote accumulation at melanoma sites and maximize the therapeutic effect. Devel-oped liposomal formulations showed a low mean size (around 100 nm), high homogeneity (PdI100 μM). Cell cycle analysis revealed an arrest in G0/G1 phase by Free-ST004 in all cell lines. In turn, LIP-ST004 led to a G0/G1 halt in B16F10, and to an arrest in S phase in A375 and MNT-1 cells. Preliminary mechanistic studies suggest gold-based inhibition of glycerol permeation through aquaglyceroporin 3 (AQP3) in human red blood cells used as a model. The proof-of-concept of the antimelanoma properties of LIP-ST004 was obtained in subcutaneous and metastatic murine melanoma models. In the latter, results showed a significant reduction on lung metastases in animals receiving LIP-ST004, com-pared to free gold complex and DTIC. Globally, this study highlights the antimelanoma potential of a new gold-based complex.

Food-borne transmission is a recognized route for many viruses associated with gastrointestinal, hepatic or neurological diseases. Therefore, it is essential to identify new bioactive compounds with broad-spectrum antiviral activity is needed to exploit innovative solutions against these hazards. Lately, antimicrobial peptides (AMPs) have been recognized as promising antiviral agents. Indeed, while the antibacterial and antifungal effects of these molecules have been widely reported, their use as potential antiviral agents has not yet been fully investigated. Herein, the antiviral activity of previously identified or newly designed AMPs, was evaluated against the non-enveloped RNA viruses, Hepatitis A virus (HAV), and Murine Norovirus (MNV), a surrogate for human Norovirus. Moreover, specific assays were performed to recognize at which stage of the viral infection cycle the peptides could function. Results showed that almost all peptides displayed virucidal effects with about 90% of infectivity reduction on HAV or MNV. However, the decapeptide RiLK1 demonstrated, together with its antibacterial and antifungal properties, a notable reduction in viral infection for both HAV and MNV, possibly through direct interaction with viral particles or inhibition of the viral bonding to the cell receptors. Hence, RiLK1 could represent a versatile ‘antimicrobial agent effective against various foodborne pathogens including viruses, bacteria, and fungi.

Background: We previously reported that human keratinocytes express protease-activated receptor (PAR)-2 and play an important role in activated protein C (APC)-induced cutaneous wound healing. This study investigated the involvement of PAR-2 in the production of gelatinolytic matrix metalloproteinases (MMP)-2 and -9 by APC during cutaneous wound healing. Methods: Full-thickness excisional wounds were made on the dorsum of male C57BL/6 mice. Wounds were treated with APC on days 1, 2, and 3 post-wounding. Cultured neonatal foreskin keratinocytes were treated with APC with or without intact PAR-2 signalling to examine the effects on MMP-2 and MMP-9 production. Murine dermal fibroblasts from PAR2 knock-out (KO) mice were also assessed. MMP-2 and -9 were measured by gelatin zymography, fluorometric assay, and immunohistochemistry. Results: APC accelerated wound healing in WT mice, but had negligible effect in PAR-2 KO mice. APC stimulated murine cutaneous wound healing was associated with differential 0temporal production of MMP-2 and MMP-9, with the latter peaking on Day 1 and the former on Day 6. In-hibition of PAR-2 in human keratinocytes reduced APC-induced MMP-2 activity 25~50, but had little effect on MMP-9. Similarly, APC-induced MMP-2 activation was reduced by 40% in cultured dermal fibroblasts derived from PAR-2 KO mice. Conclusion: This study shows for the first time that PAR-2 is essential for APC-induced MMP-2 production. Considering the important role of MMP-2 in wound healing, this work helps explain the underlying mechanisms of action of APC to promote wound healing through PAR2.

The regulatory approvals of tumor agnostic therapies have led to reevaluation of the drug development process. Conventional models of drug development are histology-based. On the other hand, tumor agnostic drug development of a new drug (or combination) focuses on targeting a common genomic biomarker in multiple cancers, regardless of histology. Basket-like clinical trials with multiple cohorts allow clinicians to evaluate pan-cancer efficacy and toxicity. There are currently 8 tumor agnostic approvals granted by the Food and Drug Administration (FDA). This includes two immune checkpoint inhibitors, and 5 targeted therapy agents. Pembrolizumab is an anti-PD-1 antibody that was the first FDA approved tumor agnostic treatment for unresectable or metastatic microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) solid tumors in 2017. It was later approved for tumor mutational burden-high (TMB-H) solid tumors, although the TMB cut-off used is still debated. Subsequently, in 2021, another anti-PD-1 antibody, Dostarlimab was also approved for dMMR solid tumors in the refractory setting. Patients with fusion-positive cancers are typically difficult to treat due to their rare prevalence and distribution. Gene rearrangements or fusions are present in a variety of tumors. neurotrophic tyrosine kinase (NTRK) fusions are present in a range of pediatric and adult solid tumors in varying frequency. Larotrectinib and entrectinib were approved for neurotrophic tyrosine kinase (NTRK) fusion-positive cancers. Similarly, selpercatinib was approved for Rearranged During Transfection (RET) fusion-positive solid tumors. FDA approved the first combination therapy of dabrafenib, a B-Raf Proto-Oncogene Serine/Threonine Kinase (BRAF) inhibitor, plus trametinib, a mitogen-activated protein kinase (MEK) inhibitor for patients 6 months or older with unresectable or metastatic tumors (except colorectal cancer) carrying BRAFV600E mutation. The most recent FDA tumor agnostic approval is of fam-trastuzumab deruxtecan-nxki (T-Dxd) for HER2-positive solid tumors. It is important to identify and expeditiously develop drugs that have the potential to provide clinical benefit across tumor types.