Muhammad Nadeem Asghar
Åbo Akademi, Biosciences, Cell Biology, Department Member
Research Interests: IBD, Cell Biology, Microflora of the Gut, Apoptosis, Multidisciplinary, and 20 moreVancomycin, Antibodies, Gut Microbiome, Cell line, Mice, Female, Animals, Drug Resistance, Intestine, Male, Keratin, Phosphorylation, Anti-Bacterial Agents, Cell Proliferation, Imipenem, Colon, Focal Adhesion Kinase, Gene expression profiling, Keratins, and Immunoblotting
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Aims: To detect the association between the use of an intrauterine contraceptive device (IUCD) and the presence of Trichomonas vaginalis (Tv) in the vaginal smears. Study design and setting: Vaginal smears were collected from 800 women... more
Aims: To detect the association between the use of an intrauterine contraceptive device (IUCD) and the presence of
Trichomonas vaginalis (Tv) in the vaginal smears.
Study design and setting: Vaginal smears were collected from 800 women who attended the Gynaecology and
Obstetrics unit at Federal Government Hospital (Polyclinic) Islamabad, between June 1995 – June 1997.
Results: Among 45 IUCD users, 15 women were positive for Tv (33.33%). Forty two of 755 non-users were also positive
for Tv (5.56%). There was a significant correlation between the use of IUCD and the presence of Tv (p<0.05).
The data also indicated that the prolonged use (>3 years) of copper-IUCD may promote the growth of Tv in the vaginal
mucosa.
Conclusion: The use of copper IUCD for a long period causes growth of Tv on the genital mucosa so special attention
should be paid to women who have prolonged copper-IUCD for the possible presence of Tv.
Trichomonas vaginalis (Tv) in the vaginal smears.
Study design and setting: Vaginal smears were collected from 800 women who attended the Gynaecology and
Obstetrics unit at Federal Government Hospital (Polyclinic) Islamabad, between June 1995 – June 1997.
Results: Among 45 IUCD users, 15 women were positive for Tv (33.33%). Forty two of 755 non-users were also positive
for Tv (5.56%). There was a significant correlation between the use of IUCD and the presence of Tv (p<0.05).
The data also indicated that the prolonged use (>3 years) of copper-IUCD may promote the growth of Tv in the vaginal
mucosa.
Conclusion: The use of copper IUCD for a long period causes growth of Tv on the genital mucosa so special attention
should be paid to women who have prolonged copper-IUCD for the possible presence of Tv.
Research Interests:
Keratin 8 (K8) is a major intermediate filament protein present in enterocytes and serves an antiapoptotic function in hepatocytes. K8-null mice develop colonic hyperplasia and colitis that are reversed after antibiotic treatment. To... more
Keratin 8 (K8) is a major intermediate filament protein present in enterocytes and serves an antiapoptotic function in hepatocytes. K8-null mice develop colonic hyperplasia and colitis that are reversed after antibiotic treatment. To investigate the pathways that underlie the mechanism of colonocyte hyperplasia and the normalization of the colonic phenotype in response to antibiotics, we performed genome-wide microarray analysis. Functional annotation of genes that are differentially regulated in K8(-/-) and K8(+/+) isolated colon crypts (colonocytes) identified apoptosis as a major altered pathway. Exposure of K8(-/-) colonocytes or colon organ ("organoid") cultures, but not K8(-/-) small intestine organoid cultures, to apoptotic stimuli showed, surprisingly, that they are resistant to apoptosis compared with their wild-type counterparts. This resistance is not related to inflammation per se because T-cell receptor α-null (TCR-α(-/-)) and wild-type colon cultures respond similarly upon induction of apoptosis. Following antibiotic treatment, K8(-/-) colonocytes and organ cultures become less resistant to apoptosis and respond similarly to the wild-type colonocytes. Antibiotics also normalize most differentially up-regulated genes, including survivin and β4-integrin. Treatment of K8(-/-) mice with anti-β4-integrin antibody up-regulated survivin, and induced phosphorylation of focal adhesion kinase with decreased activation of caspases. Therefore, unlike the proapoptotic effect of K8 mutation or absence in hepatocytes, lack of K8 confers resistance to colonocyte apoptosis in a microflora-dependent manner.
Research Interests:
Simple-type epithelial keratins are intermediate filament proteins important for mechanical stability and stress-protection. Keratin mutations predispose to human liver disorders, while their roles in intestinal diseases remain unclear.... more
Simple-type epithelial keratins are intermediate filament proteins important for mechanical stability and stress-protection. Keratin mutations predispose to human liver disorders, while their roles in intestinal diseases remain unclear. Absence of keratin 8 (K8) in mice leads to colitis, decreased Na/Cl uptake, protein mistargeting and longer crypts, suggesting that keratins contribute to intestinal homeostasis. We describe the rate-limiting enzyme of the
ketogenic energy metabolism pathway, mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme-A-synthase-2 HMGCS2), as a major down-regulated protein in K8-/- colon. K8 absence leads to decreased quantity and activity of HMGCS2, and the down-regulation is not dependent on the inflammatory state since HMGCS2 is not decreased in dextran sulphate sodium-induced colitis. Peroxisome proliferator-activated receptor α (PPARα), a transcriptional activator of HMGCS2, is similarly down-regulated. Ketogenic conditions, starvation or ketogenic diet, increase K8+/+ HMGCS2, while this response is blunted in the K8-/- colon. Microbiota-produced short chain fatty acids (SCFA), substrates in the colonic ketone body pathway, are increased in stool, which correlates with decreased levels of their
transporter MCT1. Microbial populations, including the main SCFA-butyrate producers in the colon, were not altered after K8 inactivation. In summary, the regulation of the SCFA-MCT1-
HMGCS2 axis is disrupted in K8-/- colonocytes, suggesting a role for keratins in colonocyte energy metabolism and homeostasis.
ketogenic energy metabolism pathway, mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme-A-synthase-2 HMGCS2), as a major down-regulated protein in K8-/- colon. K8 absence leads to decreased quantity and activity of HMGCS2, and the down-regulation is not dependent on the inflammatory state since HMGCS2 is not decreased in dextran sulphate sodium-induced colitis. Peroxisome proliferator-activated receptor α (PPARα), a transcriptional activator of HMGCS2, is similarly down-regulated. Ketogenic conditions, starvation or ketogenic diet, increase K8+/+ HMGCS2, while this response is blunted in the K8-/- colon. Microbiota-produced short chain fatty acids (SCFA), substrates in the colonic ketone body pathway, are increased in stool, which correlates with decreased levels of their
transporter MCT1. Microbial populations, including the main SCFA-butyrate producers in the colon, were not altered after K8 inactivation. In summary, the regulation of the SCFA-MCT1-
HMGCS2 axis is disrupted in K8-/- colonocytes, suggesting a role for keratins in colonocyte energy metabolism and homeostasis.
Research Interests:
AIMS/HYPOTHESIS: Dietary and microbial factors and the gut immune system are important in autoimmune diabetes. We evaluated inflammatory activity in the whole gut in prediabetic NOD mice using ex vivo imaging of reactive oxygen and... more
AIMS/HYPOTHESIS:
Dietary and microbial factors and the gut immune system are important in autoimmune diabetes. We evaluated inflammatory activity in the whole gut in prediabetic NOD mice using ex vivo imaging of reactive oxygen and nitrogen species (RONS), and correlated this with the above-mentioned factors.
METHODS:
NOD mice were fed a normal diet or an anti-diabetogenic casein hydrolysate (CH) diet. RONS activity was detected by chemiluminescence imaging of the whole gut. Proinflammatory and T cell cytokines were studied in the gut and islets, and dietary effects on gut microbiota and short-chain fatty acids were determined.
RESULTS:
Prediabetic NOD mice displayed high RONS activity in the epithelial cells of the distal small intestine, in conjunction with a proinflammatory cytokine profile. RONS production was effectively reduced by the CH diet, which also controlled (1) the expression of proinflammatory cytokines and colonisation-dependent RegIIIγ (also known as Reg3g) in ileum; (2) intestinal T cell activation; and (3) islet cytokines. The CH diet diminished microbial colonisation, increased the Bacteroidetes:Firmicutes ratio, and reduced lactic acid and butyric acid production in the gut.
CONCLUSIONS/INTERPRETATION:
Epithelial RONS production and proinflammatory T cell activation appears in the ileum of NOD mice after weaning to normal laboratory chow, but not after weaning to an anti-diabetogenic CH diet. Our data suggest a link between dietary factors, microbial colonisation and mucosal immune activation in NOD mice.
Dietary and microbial factors and the gut immune system are important in autoimmune diabetes. We evaluated inflammatory activity in the whole gut in prediabetic NOD mice using ex vivo imaging of reactive oxygen and nitrogen species (RONS), and correlated this with the above-mentioned factors.
METHODS:
NOD mice were fed a normal diet or an anti-diabetogenic casein hydrolysate (CH) diet. RONS activity was detected by chemiluminescence imaging of the whole gut. Proinflammatory and T cell cytokines were studied in the gut and islets, and dietary effects on gut microbiota and short-chain fatty acids were determined.
RESULTS:
Prediabetic NOD mice displayed high RONS activity in the epithelial cells of the distal small intestine, in conjunction with a proinflammatory cytokine profile. RONS production was effectively reduced by the CH diet, which also controlled (1) the expression of proinflammatory cytokines and colonisation-dependent RegIIIγ (also known as Reg3g) in ileum; (2) intestinal T cell activation; and (3) islet cytokines. The CH diet diminished microbial colonisation, increased the Bacteroidetes:Firmicutes ratio, and reduced lactic acid and butyric acid production in the gut.
CONCLUSIONS/INTERPRETATION:
Epithelial RONS production and proinflammatory T cell activation appears in the ileum of NOD mice after weaning to normal laboratory chow, but not after weaning to an anti-diabetogenic CH diet. Our data suggest a link between dietary factors, microbial colonisation and mucosal immune activation in NOD mice.
Research Interests:
Keratins (K) are important for epithelial stress protection as evidenced by keratin mutations predisposing to human liver diseases and possibly inflammatory bowel diseases. A role for K8 in the colon is supported by the ulcerative... more
Keratins (K) are important for epithelial stress protection as evidenced by keratin mutations predisposing to human liver diseases and possibly inflammatory bowel diseases. A role for
K8 in the colon is supported by the ulcerative colitis-phenotype with epithelial hyperproliferation and abnormal ion transport in K8-knockout (K8−/−) mice. The heterozygote knockout (K8+/−) colon appears normal but displays a partial ion transport-defect. Characterizing the colonic phenotype we show that K8+/− colon expresses ~50%less keratins compared to K8 wild type (K8+/+) but de novo K7 expression is observed in the top-most cells of the K8+/− and K8−/− crypts. The K8+/− colonic crypts are significantly longer due to increased epithelial hyperproliferation, but display no defects in apoptosis or inflammation in contrast to K8−/−.
When exposed to colitis using the dextran sulphate sodium-model, K8+/− mice showed higher disease sensitivity and delayed recovery compared to K8+/+ littermates. Therefore,
the K8+/− mild colonic phenotype correlates with decreased keratin levels and increased sensitivity to experimental colitis, suggesting that a sufficient amount of keratin is needed for efficient stress protection in the colonic epithelia.
K8 in the colon is supported by the ulcerative colitis-phenotype with epithelial hyperproliferation and abnormal ion transport in K8-knockout (K8−/−) mice. The heterozygote knockout (K8+/−) colon appears normal but displays a partial ion transport-defect. Characterizing the colonic phenotype we show that K8+/− colon expresses ~50%less keratins compared to K8 wild type (K8+/+) but de novo K7 expression is observed in the top-most cells of the K8+/− and K8−/− crypts. The K8+/− colonic crypts are significantly longer due to increased epithelial hyperproliferation, but display no defects in apoptosis or inflammation in contrast to K8−/−.
When exposed to colitis using the dextran sulphate sodium-model, K8+/− mice showed higher disease sensitivity and delayed recovery compared to K8+/+ littermates. Therefore,
the K8+/− mild colonic phenotype correlates with decreased keratin levels and increased sensitivity to experimental colitis, suggesting that a sufficient amount of keratin is needed for efficient stress protection in the colonic epithelia.
Research Interests:
Background: Traditional techniques analyzing mouse colitis are invasive, laborious, or indirect. Development of in vivo imaging techniques for specific colitis processes would be useful for monitoring disease progression and/or treatment... more
Background: Traditional techniques analyzing mouse colitis are invasive, laborious, or indirect. Development of in vivo imaging techniques for specific colitis processes would be useful for monitoring disease progression and/or treatment effectiveness. The aim was to evaluate the applicability of
the chemiluminescent probe L-012, which detects reactive oxygen and nitrogen species, for in vivo colitis imaging.
Methods: Two genetic colitis mouse models were used; K8 knockout (K82/2) mice, which develop early colitis and the nonobese diabetic mice, which develop a transient subclinical colitis. Dextran sulphate sodium was used as a chemical colitis model. Mice were anesthetized, injected intraperitoneally with L-012, imaged, and quantified for chemiluminescent signal in the abdominal region using an IVIS camera system.
Results: K82/2 and nonobese diabetic mice showed increased L-012-mediated chemiluminescence from the abdominal region compared with control mice. L-012 signals correlated with the colitis phenotype assessed by histology and myeloperoxidase staining. Although L-012 chemiluminescence enabled detection of dextran sulphate sodium–induced colitis at an earlier time point compared with traditional methods, large mouse-to-mouse variations
were noted. In situ and ex vivo L-012 imaging as well as [18F]FDG-PET imaging of K82/2 mice confirmed that the in vivo signals originated from the distal colon. Using L-012 in vivo imaging, a wide variation in reactive oxygen and nitrogen species in young, but not aging, K82/2 mice was determined, which had higher signals compared with K8+/+ mice.
Conclusions: In vivo imaging using L-012 is a useful, simple, and cost-effective tool to study the level and longitudinal progression of genetic and possibly chemical murine colitis.
the chemiluminescent probe L-012, which detects reactive oxygen and nitrogen species, for in vivo colitis imaging.
Methods: Two genetic colitis mouse models were used; K8 knockout (K82/2) mice, which develop early colitis and the nonobese diabetic mice, which develop a transient subclinical colitis. Dextran sulphate sodium was used as a chemical colitis model. Mice were anesthetized, injected intraperitoneally with L-012, imaged, and quantified for chemiluminescent signal in the abdominal region using an IVIS camera system.
Results: K82/2 and nonobese diabetic mice showed increased L-012-mediated chemiluminescence from the abdominal region compared with control mice. L-012 signals correlated with the colitis phenotype assessed by histology and myeloperoxidase staining. Although L-012 chemiluminescence enabled detection of dextran sulphate sodium–induced colitis at an earlier time point compared with traditional methods, large mouse-to-mouse variations
were noted. In situ and ex vivo L-012 imaging as well as [18F]FDG-PET imaging of K82/2 mice confirmed that the in vivo signals originated from the distal colon. Using L-012 in vivo imaging, a wide variation in reactive oxygen and nitrogen species in young, but not aging, K82/2 mice was determined, which had higher signals compared with K8+/+ mice.
Conclusions: In vivo imaging using L-012 is a useful, simple, and cost-effective tool to study the level and longitudinal progression of genetic and possibly chemical murine colitis.