Germline gain-of-function MMP11 variant results in an aggressive form of colorectal cancer

Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.     

The R7 subfamily of RGS proteins assists tachyphylaxis and acute tolerance at mu-opioid receptors.

Members of the R7 subfamily of regulators of G-protein signaling (RGS) proteins (RGS6, RGS7, RGS9-2, and RGS11) are found in the mouse CNS. The expression of these proteins was effectively reduced in different neural structures by blocking their mRNA with antisense oligodeoxynucleotides (ODNs). This was achieved without noticeable changes in the binding characteristics of labeled beta-endorphin to opioid receptors. Knockdown of R7 proteins enhanced the potency of antinociception promoted by morphine and [D-Ala(2), N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO)-both agonists at mu-opioid receptors. The duration of morphine analgesia was greatly increased in RGS9-2 and in RGS11 knockdown mice. The impairment of R7 proteins brought about different changes in the analgesic activity of selective delta agonists. Knockdown of RGS11 reduced [D-Ala(2)]deltorphin II analgesic effects. Those of RGS6 and RGS9-2 proteins caused [D-Ala(2)]deltorphin II to produce a smoothened time-course curve-the peak effect blunted and analgesia extended during the declining phase. RGS9-2 impairment also promoted a similar pattern of change for [D-Pen(2,5)]-enkephalin (DPDPE). RGS7-deficient mice showed an increased response to both [D-Ala(2)]deltorphin II and DPDPE analgesic effects. A single intracerebroventricular (i.c.v.) ED(80) analgesic dose of morphine gave rise to acute tolerance in control mice, but did not promote tolerance in RGS6, RGS7, RGS9-2, or RGS11 knockdown animals. Thus, R7 proteins play a critical role in agonist tachyphylaxis and acute tolerance at mu-opioid receptors, and show differences in their modulation of delta-opioid receptors.     

Phenotype traits associated with different alleles at the RPS5 locus in Saccharomyces cerevisiae

Summary The RPS5 gene has been characterised through its ability to reduce invertase production by the SUC5 gene. In this paper we show that RPS5 acts by maintaining low levels of SUC5 mRNA. We also show that RPS5 acts on the SUC1 and SUC4 genes but not on SUC2 and SUC3, which are members of the SUC family. RPS5 also shows a pleiotropic effect on the amount of mitochondrial cytochromes.     

Molecular characterization of a coxsackievirus A24 variant that caused an outbreak of acute haemorrhagic conjunctivitis in Spain, 2004

BACKGROUND: Coxsackievirus A24 variant is one of the major etiological agents involved in acute haemorrhagic conjunctivitis. STUDY DESIGN: An outbreak of acute hemorrhagic conjunctivitis occurred in the Southeast of Spain between September and November 2004. Cellular and molecular methods were used to identify and characterize the viral agent associated with the epidemic. RESULTS: Enterovirus was detected in the conjunctival swabs of 35 patients. None of the viruses isolated could be typed by conventional neutralization assays; however, amplification and sequencing of the 3'-end VP1 region of 19 of the samples identified coxsackievirus A24 variant as the serotype causing the outbreak. Phylogenetic analysis of the 5'-half VP1 region of the genome revealed that Spanish sequences, like other strains isolated during outbreaks of hemorrhagic conjunctivitis in American and African countries in 2003 and 2004, were closely related to the isolates detected in Korea (2002), thus proving their worldwide spread. CONCLUSIONS: This is the first report of an epidemic of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant in Spain. Molecular typing in combination with phylogenetic analysis is useful to study the enterovirus epidemiology associated with epidemics.     

Analogies and differences between ω-conotoxins MVIIC and MVIID: binding sites and functions in bovine chromaffin cells

 The characteristics of the binding sites for the Conus magus toxins ω-conotoxin MVIIC and ω-conotoxin MVIID, as well as their effects on K⁺-evoked ⁴⁵Ca²⁺ entry and whole-cell Ba²⁺ currents (I _Ba), and K⁺-evoked catecholamine secretion have been studied in bovine adrenal chromaffin cells. Binding of [¹²⁵I] ω-conotoxin GVIA to bovine adrenal medullary membranes was displaced by ω-conotoxins GVIA, MVIIC and MVIID with IC₅₀ values of around 0.1, 4 and 100 nM, respectively. The reverse was true for the binding of [¹²⁵I] ω-conotoxin MVIIC, which was displaced by ω-conotoxins MVIIC, MVIID and GVIA with IC₅₀ values of around 30, 80 and 1.200 nM, respectively. The sites recognized by ω-conotoxins MVIIC and MVIID in bovine brain exhibited higher affinities (IC₅₀ values of around 1 nM). Both ω-conotoxin MVIIC and MVIID blocked I _Ba by 70–80%; the higher the [Ba²⁺]_o of the extracellular solution the lower the blockade induced by ω-conotoxin MVIIC. This was not the case for ω-conotoxin MVIID; high Ba²⁺ (10 mM) slowed down the development of blockade but the maximum blockade achieved was similar to that obtained in 2 mM Ba²⁺. A further difference between the two toxins concerns their reversibility; washout of ω-conotoxin MVIIC did not reverse the blockade of I _Ba while in the case of ω-conotoxin MVIID a partial, quick recovery of current was produced. This component was irreversibly blocked by ω-conotoxin GVIA, suggesting that it is associated with N-type Ca²⁺ channels. Blockade of K⁺-evoked ⁴⁵Ca²⁺ entry produced results which paralleled those obtained by measuring I _Ba. Thus, 1 μM of each of ω-conotoxin GVIA and MVIIA inhibited Ca²⁺ uptake by 25%, while 1 μM of each of ω-conotoxin MVIIC and MVIID caused a 70% blockade. K⁺-evoked catecholamine secretory responses were not reduced by ω-conotoxin GVIA (1 μM). In contrast, at 1 μM both ω-conotoxin MVIIC and MVIID reduced the exocytotic response by 70%. These data strengthen the previously established conclusion that Q-type Ca²⁺ channels that contribute to the regulation of secretion and are sensitive to ω-conotoxins MVIIC and MVIID are present in bovine chromaffin cells. These channels, however, seem to possess binding sites for ω-conotoxins MVIIC and MVIID whose characteristics differ considerably from those described to occur in the brain; they might represent a subset of Q-type Ca²⁺ channels or an entirely new subtype of voltage-dependent high-threshold Ca²⁺ channel. Received: 16 April 1997 / Received after revision: 10 July 1997 / Accepted: 23 July 1997     

Revisión de las terapias biológicas en la enfermedad inmunomediada del oído interno

Introduction and objectivesImmune-mediated inner ear disease (IMIED) is one of the few reversible forms of sensorineural hearing loss. Treatment is based on high-dose corticosteroids, although long-term therapy is associated with serious adverse effects; this has led to the use of other agents or different routes of administration such as transtympanic delivery. This study analyses the role of biological agents in IMIED management.Material and methodsWe searched PUBMED for studies that examined the response to treatment with different biological agents in patients with IMIED. The following data were extracted from the selected studies and entered into a standardised database: exclusion and inclusion criteria, characteristics of the patients studied, treatment, outcome measures and response rates achieved.ResultsThirteen studies were included in this review. A TNF alpha inhibitor (etanercept, infliximab, adalimumab) was used in 8 studies, an IL-1 antagonist (anakinra) was used in 3 studies and rituximab, an antibody directed against the CD20 surface antigen on B lymphocytes, was evaluated in 2 studies. Most studies achieved a hearing improvement or stabilisation in more than 70% of treated patients.ConclusionsBiological agents can play a role in the management of patients with IMIED, at least in those patients who do not respond to conventional therapy or whose hearing is not stabilised. However, specially-designed randomised controlled clinical trials are needed to assess their effectiveness.     

Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral,Contralateral and Bilateral Noise

The amplitude modulations (AMs) in speech signals are useful cues for speech recognition. Several adaptation mechanisms may make the detection of AM in noisy backgrounds easier when the AM carrier is presented later rather than earlier in the noise. The aim of the present study was to characterize temporal adaptation to noise in AM detection. AM detection thresholds were measured for monaural (50 ms, 1.5 kHz) pure-tone carriers presented at the onset (‘early’ condition) and 300 ms after the onset (‘late’ condition) of ipsilateral, contralateral, and bilateral (diotic) broadband noise, as well as in quiet. Thresholds were 2–4 dB better in the late than in the early condition for the three noise lateralities. The temporal effect held for carriers at equal sensation levels, confirming that it was not due to overshoot on carrier audibility. The temporal effect was larger for broadband than for low-band contralateral noises. Many aspects in the results were consistent with the noise activating the medial olivocochlear reflex (MOCR) and enhancing AM depth in the peripheral auditory response. Other aspects, however, indicate that central masking and adaptation unrelated to the MOCR also affect both carrier-tone and AM detection and are involved in the temporal effects.