Cytotoxic activities of ethanolic crude extracts from fruiting bodies of bamboo mushrooms (Dictyophora spp.) against cholangiocarcinoma cells

Cholangiocarcinoma (CCA) is a highly progressive tumor. The standard chemotherapy varies in its effectiveness, with generally low efficacy. So, the discovery of novel chemotherapy is still required. The objective of this preliminary study was to determine the cytotoxic effects induced by three kinds of bamboo mushrooms (Dictyophora indusiata or Chinese bamboo mushroom; Ch-DTP, Short skirt bamboo mushroom (Thai isolate); Th-DTP, and orange skirt bamboo mushroom; Or-DTP) on CCA cell

Invasion of the central nervous system by Cryptococcus neoformans requires a secreted fungal metalloprotease.

UnlabelledCryptococcus spp. cause life-threatening fungal infection of the central nervous system (CNS), predominantly in patients with a compromised immune system. Why Cryptococcus neoformans has this remarkable tropism for the CNS is not clear. Recent research on cerebral pathogenesis of C. neoformans revealed a predominantly transcellular migration of cryptococci across the brain endothelium; however, the identities of key fungal virulence factors that function specifically to invade the CNS remain unresolved. Here we found that a novel, secreted metalloprotease (Mpr1) that we identified in the extracellular proteome of C. neoformans (CnMpr1) is required for establishing fungal disease in the CNS. Mpr1 belongs to a poorly characterized M36 class of fungalysins that are expressed in only some fungal species. A strain of C. neoformans lacking the gene encoding Mpr1 (mpr1Δ) failed to breach the endothelium in an in vitro model of the human blood-brain barrier (BBB). A mammalian host infected with the mpr1Δ null strain demonstrated significant improvement in survival due to a reduced brain fungal burden and lacked the brain pathology commonly associated with cryptococcal disease. The in vivo studies further indicate that Mpr1 is not required for fungal dissemination and Mpr1 likely targets the brain endothelium specifically. Remarkably, the sole expression of CnMPR1 in Saccharomyces cerevisiae resulted in a robust migration of yeast cells across the brain endothelium, demonstrating Mpr1's specific activity in breaching the BBB and suggesting that Mpr1 may function independently of the hyaluronic acid-CD44 pathway. This distinct role for Mpr1 may develop into innovative treatment options and facilitate a brain-specific drug delivery platform.ImportanceCryptococcus neoformans is a medically relevant fungal pathogen causing significant morbidity and mortality, particularly in immunocompromised individuals. An intriguing feature is its strong neurotropism, and consequently the hallmark of cryptococcal disease is a brain infection, cryptococcal meningoencephalitis. For C. neoformans to penetrate the central nervous system (CNS), it first breaches the blood-brain barrier via a transcellular pathway; however, the identities of fungal factors required for this transmigration remain largely unknown. In an effort to identify extracellular fungal proteins that could mediate interactions with the brain endothelium, we undertook a proteomic analysis of the extracellular proteome and identified a secreted metalloprotease (Mpr1) belonging to the M36 class of fungalysins. Here we found that Mpr1 promotes migration of C. neoformans across the brain endothelium and into the CNS by facilitating attachment of cryptococci to the endothelium surface, thus underscoring the critical role of M36 proteases in fungal pathogenesis

Cytotoxic activities of ethanolic crude extracts from fruiting bodies of bamboo mushrooms (Dictyophora spp.) against cholangiocarcinoma cells

Introduction: Cholangiocarcinoma (CCA) is a highly progressive tumor. The standard chemotherapy varies in its effectiveness, with generally low efficacy. So, the discovery of novel chemotherapy is still required. The objective of this preliminary study was to determine the cytotoxic effects induced by three kinds of bamboo mushrooms (Dictyophora indusiata or Chinese bamboo mushroom; Ch-DTP, Short skirt bamboo mushroom (Thai isolate); Th-DTP, and orange skirt bamboo mushroom; Or-DTP) on CCA cells. Materials and methods: CCA cell lines, including CL-6, HuCCT1, HuH28, and OUMS normal fibroblast cells, were treated with various concentrations of DTP extracts. The MTT assay was used to determine cytotoxicity, and cell morphology was observed by using phase-contrast microscopy. Results and discussion: The results suggested that Ch-DTP effectively killed all three CCA cell lines in both low (0.3 mg/mL) and high (0.6 mg/mL) doses, but Th-DTP and Or-DTP had significantly reduced cell viability only at high doses (p<0.001). Ch-DTP had the best effect by showing a response of more than 50% at a concentration of 0.3 mg/mL. Th-DTP had moderate effects at a concentration of lower than 0.6 mg/mL but worthwhile at higher concentrations, whereas Or-DTP had limited effects at concentrations of 0.4 mg/mL and downward, although the effects were significantly increased in the higher concentration range. Morphology of the Ch-DTP treated cells was greatly transformed both at low and high doses, but Th-DTP and Or-DTP showed definite alteration only at high doses. The morphological changes revealed apoptotic induction. In OUMS cells, no effects were recognized with any of the three DTPs. Conclusion: This study indicated that DTP extracts could induce cytotoxicity in cholangiocarcinoma, with a high potential of being an effective therapeutic agent. Graphical abstract

The blood–brain barrier internalises Cryptococcus neoformans via the EphA2‐tyrosine kinase receptor

Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis most commonly in populations with impaired immunity. Here, we resolved the transcriptome of the human brain endothelium challenged with C.&nbsp;neoformans to establish whether C.&nbsp;neoformans invades the CNS by co-opting particular signalling pathways as a means to promote its own entry. Among the 5 major pathways targeted by C.&nbsp;neoformans, the EPH-EphrinA1 (EphA2) tyrosine kinase receptor-signalling pathway was examined further. Silencing the EphA2 receptor transcript in a human brain endothelial cell line or blocking EphA2 activity with an antibody or chemical inhibitor prevented transmigration of C.&nbsp;neoformans in an in vitro model of the blood-brain barrier (BBB). In contrast, treating brain endothelial cells with an EphA2 chemical agonist or an EphA2 ligand promoted greater migration of fungal cells across the BBB. C.&nbsp;neoformans activated the EPH-tyrosine kinase pathway through a CD44-dependent phosphorylation of EphA2, promoting clustering and internalisation of EphA2 receptors. Moreover, HEK293T cells expressing EphA2 revealed an association between EphA2 and C.&nbsp;neoformans that boosted internalisation of C.&nbsp;neoformans. Collectively, the results suggest that C.&nbsp;neoformans promotes EphA2 activity via CD44, and this in turn creates a permeable barrier that facilitates the migration of C.&nbsp;neoformans across the BBB

The structure-function analysis of the Mpr1 metalloprotease determinants of activity during migration of fungal cells across the blood-brain barrier.

Cryptococcal meningoencephalitis, the most common form of cryptococcosis, is caused by the opportunistic fungal pathogen, Cryptococcus neoformans. Molecular strategies used by C. neoformans to invade the central nervous system (CNS) have been the focus of several studies. Recently, the role of a novel secreted metalloprotease (Mpr1) in the pathogenicity of C. neoformans was confirmed by studies demonstrating that Mpr1 mediated the migration of fungal cells into the CNS. Given this central function, the aim here was to identify the molecular determinants of Mpr1 activity and resolve their role in the migration of cryptococci across the blood-brain barrier (BBB). The Mpr1 protein belongs to an understudied group of metalloproteases of the M36 class of fungalysins unique to fungi. They are generally synthesized as propeptides with fairly long prodomains and highly conserved regions within their catalytic core. Through structure-function analysis of Mpr1, our study identified the prodomain cleavage sites of Mpr1 and demonstrated that when mutated, the prodomain appears to remain attached to the catalytic C-terminus of Mpr1 rendering a nonfunctional Mpr1 protein and an inability for cryptococci to cross the BBB. We found that proteolytic activity of Mpr1 was dependent on the coordination of zinc with two histidine residues in the active site of Mpr1, since amino acid substitutions in the HExxH motif abolished Mpr1 proteolytic activity and prevented the migration of cryptococci across the BBB. A phylogenetic analysis of Mpr1 revealed a distinct pattern likely reflecting the neurotropic nature of C. neoformans and the specific function of Mpr1 in breaching the BBB. This study contributes to a deeper understanding of the molecular regulation of Mpr1 activity and may lead to the development of specific inhibitors that could be used to restrict fungal penetration of the CNS and thus prevent cryptococcal meningoencephalitis-related deaths

Novel Type of Staphylococcal Cassette Chromosome mec Identified in Community-Acquired Methicillin-Resistant Staphylococcus aureus Strains

We identified a new type of staphylococcal cassette chromosome mec (SCCmec) from two community-acquired methicillin-resistant Staphylococcus aureus (MRSA) strains. The novel element, designated type IV SCCmec, had a unique combination of the class B mec gene complex and the type 2 ccr gene complex and was much smaller in size (21 to 24 kb) than previously identified SCCmec elements of hospital-acquired MRSA. Consistent with the strains' susceptibilities to various non-β-lactam antibiotics, the type IV SCCmec was devoid of any antibiotic resistance genes other than the mecA gene

Staphylococcal Cassette Chromosome mec (SCCmec) Typing of Methicillin-Resistant Staphylococcus aureus Strains Isolated in 11 Asian Countries: a Proposal for a New Nomenclature for SCCmec Elements

A description of staphylococcal cassette chromosome mec (SCCmec) elements carried by 615 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in 11 Asian countries is reported, and a novel nomenclatural system based on their structures is proposed. The 615 strains were classified as type 3A (370 strains), type 2A (207 strains), type 2B (32 strains), type 1B (1 strain), and nontypeable (5 strains). The previously reported type III SCCmec (DDBJ/EMBL/GenBank accession no. AB037671) carried by the MRSA strain 85/2082 was ascertained to be composed of two SCC elements, type 3A SCCmec and SCCmercury. PCR analysis indicated that 310 of 370 type 3A SCCmec strains carried both SCC elements. These strains were prevalent in eight countries: Thailand, Sri Lanka, Indonesia, Vietnam, Philippines, Saudi Arabia, India, and Singapore. The remaining 60 type 3A SCCmec strains differed with respect to the left extremity polymorphism or to the presence of ccrC. Among these, two were identified as carrying only type 3A SCCmec elements, but their left extremities differed. Type 2A SCCmec strains predominated in Korea and Japan, although the frequency of the presence of ant(4′)-1 gene downstream of mecA varied (53% for Korean strains; 93% for Japanese strains). Various SCCmec elements were identified in the tested strains, and limited numbers were identified by their multilocus sequence typing genotypes. These data suggest that numerous MRSA clones are disseminated in Asian hospitals, and these consist of minor clones that are presumed to have arisen locally and major clones that are presumed to have been introduced from other countries