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Direct visualization of HIV-enhancing endogenous amyloid fibrils in human semen.

Usmani SM, Zirafi O, Müller JA, Sandi-Monroy NL, Yadav JK, Meier C, Weil T, Roan NR, Greene WC, Walther P, Nilsson KP, Hammarström P, Wetzel R, Pilcher CD, Gagsteiger F, Fändrich M, Kirchhoff F, Münch J - Nat Commun (2014)

Bottom Line: Naturally occurring fragments of the abundant semen proteins prostatic acid phosphatase (PAP) and semenogelins form amyloid fibrils in vitro.These fibrils boost HIV infection and may play a key role in the spread of the AIDS pandemic.Our results establish semen as a body fluid that naturally contains amyloid fibrils that are exploited by HIV to promote its sexual transmission.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany.

ABSTRACT
Naturally occurring fragments of the abundant semen proteins prostatic acid phosphatase (PAP) and semenogelins form amyloid fibrils in vitro. These fibrils boost HIV infection and may play a key role in the spread of the AIDS pandemic. However, the presence of amyloid fibrils in semen remained to be demonstrated. Here, we use state of the art confocal and electron microscopy techniques for direct imaging of amyloid fibrils in human ejaculates. We detect amyloid aggregates in all semen samples and find that they partially consist of PAP fragments, interact with HIV particles and increase viral infectivity. Our results establish semen as a body fluid that naturally contains amyloid fibrils that are exploited by HIV to promote its sexual transmission.

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Related in: MedlinePlus

Endogenous amyloids partially consists of SEVI(a) Semen was treated with pre-immune (top) or anti-SEVI antiserum (α-SEVI, bottom). The amyloid/antibody complexes were pelleted, washed, and incubated with an Alexa488-coupled secondary antibody (green), and counterstained with Proteostat dye (red). Scale bar = 5 µm. (b) Immunogold-labeling of endogenous SEVI fibrils in semen. Transmission electron micrographs of semen treated with a pre-immune serum or an anti-SEVI antiserum as primary antibodies, and gold conjugated anti-rabbit secondary antibody. Scale bar = 100 nm. White arrows indicate gold particles bound to amyloid fibrils.
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Figure 3: Endogenous amyloids partially consists of SEVI(a) Semen was treated with pre-immune (top) or anti-SEVI antiserum (α-SEVI, bottom). The amyloid/antibody complexes were pelleted, washed, and incubated with an Alexa488-coupled secondary antibody (green), and counterstained with Proteostat dye (red). Scale bar = 5 µm. (b) Immunogold-labeling of endogenous SEVI fibrils in semen. Transmission electron micrographs of semen treated with a pre-immune serum or an anti-SEVI antiserum as primary antibodies, and gold conjugated anti-rabbit secondary antibody. Scale bar = 100 nm. White arrows indicate gold particles bound to amyloid fibrils.

Mentions: We next examined if endogenous amyloids may be composed of SEVI fibrils. Control experiments showed that an antiserum raised against SEVI13, but not the pre-immune serum, reacted specifically with in vitro generated Proteostat-labelled SEVI fibrils (Supplementary Fig. 7). Similarly, the SEVI antiserum recognized structures in semen that co-stained with the amyloid probe (Fig. 3a). Not all of the material that was stained with Proteostat, however, was also recognized by the SEVI antiserum (Fig. 3a). Thus, in agreement with previous results11, 17, 20 our data provide evidence that endogenous amyloids consist of fibrils formed by multiple types of peptides. To verify the fibrillar nature of the structures recognized by the SEVI antiserum, we performed TEM on semen treated with immunogold-labelled SEVI antiserum. As shown in Fig. 3b, gold conjugated anti-SEVI antibodies specifically bound to fibrils in semen, providing evidence that endogenous SEVI fibrils exist in ejaculates. Thus, endogenous amyloid fibrils consist of PAP248-286 or closely related peptides.


Direct visualization of HIV-enhancing endogenous amyloid fibrils in human semen.

Usmani SM, Zirafi O, Müller JA, Sandi-Monroy NL, Yadav JK, Meier C, Weil T, Roan NR, Greene WC, Walther P, Nilsson KP, Hammarström P, Wetzel R, Pilcher CD, Gagsteiger F, Fändrich M, Kirchhoff F, Münch J - Nat Commun (2014)

Endogenous amyloids partially consists of SEVI(a) Semen was treated with pre-immune (top) or anti-SEVI antiserum (α-SEVI, bottom). The amyloid/antibody complexes were pelleted, washed, and incubated with an Alexa488-coupled secondary antibody (green), and counterstained with Proteostat dye (red). Scale bar = 5 µm. (b) Immunogold-labeling of endogenous SEVI fibrils in semen. Transmission electron micrographs of semen treated with a pre-immune serum or an anti-SEVI antiserum as primary antibodies, and gold conjugated anti-rabbit secondary antibody. Scale bar = 100 nm. White arrows indicate gold particles bound to amyloid fibrils.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129123&req=5

Figure 3: Endogenous amyloids partially consists of SEVI(a) Semen was treated with pre-immune (top) or anti-SEVI antiserum (α-SEVI, bottom). The amyloid/antibody complexes were pelleted, washed, and incubated with an Alexa488-coupled secondary antibody (green), and counterstained with Proteostat dye (red). Scale bar = 5 µm. (b) Immunogold-labeling of endogenous SEVI fibrils in semen. Transmission electron micrographs of semen treated with a pre-immune serum or an anti-SEVI antiserum as primary antibodies, and gold conjugated anti-rabbit secondary antibody. Scale bar = 100 nm. White arrows indicate gold particles bound to amyloid fibrils.
Mentions: We next examined if endogenous amyloids may be composed of SEVI fibrils. Control experiments showed that an antiserum raised against SEVI13, but not the pre-immune serum, reacted specifically with in vitro generated Proteostat-labelled SEVI fibrils (Supplementary Fig. 7). Similarly, the SEVI antiserum recognized structures in semen that co-stained with the amyloid probe (Fig. 3a). Not all of the material that was stained with Proteostat, however, was also recognized by the SEVI antiserum (Fig. 3a). Thus, in agreement with previous results11, 17, 20 our data provide evidence that endogenous amyloids consist of fibrils formed by multiple types of peptides. To verify the fibrillar nature of the structures recognized by the SEVI antiserum, we performed TEM on semen treated with immunogold-labelled SEVI antiserum. As shown in Fig. 3b, gold conjugated anti-SEVI antibodies specifically bound to fibrils in semen, providing evidence that endogenous SEVI fibrils exist in ejaculates. Thus, endogenous amyloid fibrils consist of PAP248-286 or closely related peptides.

Bottom Line: Naturally occurring fragments of the abundant semen proteins prostatic acid phosphatase (PAP) and semenogelins form amyloid fibrils in vitro.These fibrils boost HIV infection and may play a key role in the spread of the AIDS pandemic.Our results establish semen as a body fluid that naturally contains amyloid fibrils that are exploited by HIV to promote its sexual transmission.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany.

ABSTRACT
Naturally occurring fragments of the abundant semen proteins prostatic acid phosphatase (PAP) and semenogelins form amyloid fibrils in vitro. These fibrils boost HIV infection and may play a key role in the spread of the AIDS pandemic. However, the presence of amyloid fibrils in semen remained to be demonstrated. Here, we use state of the art confocal and electron microscopy techniques for direct imaging of amyloid fibrils in human ejaculates. We detect amyloid aggregates in all semen samples and find that they partially consist of PAP fragments, interact with HIV particles and increase viral infectivity. Our results establish semen as a body fluid that naturally contains amyloid fibrils that are exploited by HIV to promote its sexual transmission.

Show MeSH
Related in: MedlinePlus